Chemistry:Grapefruit–drug interactions

From HandWiki
Short description: Drug interactions with grapefruit juice
Grapefruit Juice and Medicine May Not Mix (6774935740) - en.svg

Some fruit juices and fruits can interact with numerous drugs, in many cases causing adverse effects.[1] The effect is most studied with grapefruit and grapefruit juice,[1] but similar effects have been observed with certain other citrus fruits.[1][2][3][4]

The effect was first discovered accidentally in 1991, when a test of drug interactions with alcohol used grapefruit juice to hide the taste of the ethanol.[5][6] A 2005 medical review advised patients to avoid all citrus juices until further research clarifies the risks.[7] It was reported in 2008 that similar effects had been observed with apple juice.[2][8][9]

One whole grapefruit, or a small glass (200 mL, 6.8 US fl oz) of grapefruit juice, can cause drug overdose toxicity.[1] Fruit consumed three days before the medicine can still have an effect.[10] The relative risks of different types of citrus fruit have not been systematically studied.[1] Affected drugs typically have an auxiliary label saying "Do not take with grapefruit" on the container, and the interaction is elaborated upon in the package insert.[11] People are also advised to ask their physician or pharmacist about drug interactions.[11]

The effects are caused by furanocoumarins (and, to a lesser extent, flavonoids).[12] These chemicals inhibit key drug metabolizing enzymes, such as cytochrome P450 3A4 (CYP3A4). CYP3A4 is a metabolizing enzyme for almost 50% of drugs, and is found in the liver and small intestinal epithelial cells.[13] As a result, many drugs are affected. Inhibition of enzymes can have two different effects, depending on whether the drug is either

  1. metabolized by the enzyme to an inactive metabolite, or
  2. activated by the enzyme to an active metabolite.

In the first instance, inhibition of drug-metabolizing enzymes results in elevated concentrations of an active drug in the body, which may cause adverse effects.[11] Conversely, if the medication is a prodrug, it needs to be metabolised to be converted to the active drug. Compromising its metabolism lowers concentrations of the active drug, reducing its therapeutic effect, and risking therapeutic failure.

Low drug concentrations can also be caused when the fruit suppresses drug absorption from the intestine.[14]

History

The effect of grapefruit juice with regard to drug absorption was originally discovered in 1989 by a group led by pharmacologist David Bailey. Their first published clinical report on grapefruit drug interactions was in 1991.[5]

Polyphenols

Citrus fruits may contain various polyphenols, including naringin and furanocoumarins, such as bergamottin, dihydroxybergamottin, and bergapten.[15] Grapefruit, Seville oranges,[16] and bergamot[17] contain naringin. Furanocoumarins may have a stronger effect than naringin.[16][18]

Mechanism

Organic derivatives of furanocoumarin interfere with liver and intestinal enzyme CYP3A4 and may be responsible for the effects of grapefruit on the enzyme.[19] Cytochrome isoforms affected by grapefruit components also include CYP1A2, CYP2C9, and CYP2D6.[20][21][22][23][24] Drugs metabolized by these enzymes may have interactions with citrus chemicals.

When drugs are taken orally, they enter the gut lumen to be absorbed in the small intestine and sometimes, in the stomach. In order for drugs to be absorbed, they must pass through the epithelial cells that line the lumen wall before they can enter the hepatic portal circulation to be distributed systemically in blood circulation. Drugs are metabolized by drug-specific metabolizing enzymes in the epithelial cells. Metabolizing enzymes transform these drugs into metabolites. The primary purpose for drug metabolism is to detoxify, inactivate, solubilize and eliminate these drugs.[25][verification needed] As a result, the amount of the drug in its original form that reaches systemic circulation is reduced due to this first-pass metabolism.

Many drugs are affected by consumption of citrus juice. When the metabolizing enzyme is inhibited, less of the drug will be metabolized by it in the epithelial cells.[13] This interaction is particularly dangerous when the drug in question has a low therapeutic index, so that a small increase in blood concentration can be the difference between therapeutic effect and toxicity. Citrus juice inhibits the enzyme only within the intestines if consumed in small amounts. When larger amounts are consumed they may also inhibit the enzyme in the liver. The hepatic enzyme inhibition may cause an additional increase in potency and a prolonged metabolic half-life (prolonged metabolic half-life for all ways of drug administration).[26] The degree of the effect varies widely between individuals and between samples of juice, and therefore cannot be accounted for a priori.

Another mechanism of interaction is possibly through the multidrug resistance-associated protein 2 localized in the brush border of the enterocytes.[27][better source needed][clarification needed]

Duration and timing

Metabolism interactions

Grapefruit–drug interactions that affect the pre-systemic metabolism (i.e., the metabolism that occurs before the drug enters the blood) of drugs have a different duration of action than interactions that work by other mechanisms, such as on absorption, discussed below.[13]

The interaction is greatest when the juice is ingested with the drug or up to 4 hours before the drug.[1][10][better source needed][original research?][28]

The location of the inhibition occurs in the lining of the intestines, not within the liver.[29] The effects last because grapefruit-mediated inhibition of drug metabolizing enzymes, like CYP3A4, is irreversible;[29] that is, once the grapefruit has "broken" the enzyme, the intestinal cells must produce more of the enzyme to restore their capacity to metabolize drugs that the enzyme is used to metabolize.[13] It takes around 24 hours to regain 50% of the cell's baseline enzyme activity and it can take 72 hours for the enzyme activity to completely return to baseline. For this reason, simply separating citrus consumption and medications taken daily does not avoid the drug interaction.[10]

Absorption interactions

For medications that interact due to inhibition of OATP (organic anion-transporting polypeptides), a relative short period of time is needed to avoid this interaction, and a 4-hour interval between grapefruit consumption and the medication should suffice.[13][27] For drugs recently sold on the market, drugs have information pages (monographs) that provide information on any potential interaction between a medication and grapefruit juice.[13] Because there is a growing number of medications that are known to interact with citrus,[1] patients should consult a pharmacist or physician before consuming citrus while taking their medications.

Affected fruit

Grapefruit is not the only citrus fruit that can interact with medications.[1][2][3][4] One medical review advised patients to avoid all citrus.[7]

There are three ways to test if a fruit interacts with drugs:

  1. Test a drug–fruit combination in humans[7]
  2. Test a fruit chemically for the presence of the interacting polyphenol compounds
  3. Test a fruit genetically for the genes needed to make the interacting polyphenol compounds[30]

The first approach involves risk to trial volunteers. The first and second approaches have another problem: the same fruit cultivar could be tested twice with different results. Depending on growing and processing conditions, concentrations of the interacting polyphenol compounds can vary dramatically.[31][better source needed] The third approach is hampered by a paucity of knowledge of the genes in question.[30]

Citrus genetics and interactions

Citrus fruits clustered by genetic similarity. Most commercial varieties of citrus are hybrids of the three species at the corners of the ternary diagram, and genetically distinct hybrids often bear the same common name.[32] Fucomarin production has been inherited by some hybrid cultivars; others have not inherited the fucomarin-producing genes.

A descendant of citrus cultivars that cannot produce the problematic polyphenol compounds would presumably also lack the genes to produce them. Many citrus cultivars are hybrids of a small number of ancestral species, which have now been fully genetically sequenced.[32][33]

Many traditional citrus groups, such as true sweet oranges and lemons, seem to be bud sports, mutant descendants of a single hybrid ancestor.[34] In theory, cultivars in a bud sport group would be either all safe or all problematic. Nonetheless, new citrus varieties arriving on the market are increasingly likely to be sexually created hybrids, not asexually created sports.

The ancestry of a hybrid cultivar may not be known. Even if it is known, it is not possible to be certain that a cultivar will not interact with drugs on the basis of taxonomy, as it is not known which ancestors lack the capacity to make the problematic polyphenol compounds. Nonetheless, many of the citrus cultivars known to be problematic seem to be closely related.

Ancestral species

Pomelo (the Asian fruit that was crossed with an orange to produce grapefruit) contains high amounts of furanocoumarin derivatives. Grapefruit relatives and other varieties of pomelo have variable amounts of furanocoumarin.[7][2][35][36]

The Dancy cultivar has a small amount of pomelo ancestry,[33] but is genetically close to a non-hybrid true mandarin (unlike most commercial mandarins, which may have much more extensive hybridization). Eight Dancy fruits, all picked at one time from one tree, have been blended and tested for furanocoumarins; none were detectable.[35]

No citron or papeda seems to have been tested.

Hybrid cultivars

Both sweet oranges and bitter oranges are mandarin-pomelo hybrids.[33][34] Bitter oranges (such as the Seville oranges often used in marmalade) can interfere with drugs[37] including etoposide, a chemotherapy drug, some beta blocker drugs used to treat high blood pressure, and cyclosporine, taken by transplant patients to prevent rejection of their new organs.[8] Evidence on sweet oranges is more mixed.[7]

Tests on some tangelos (hybrids of mandarins/tangerines and pomelo or grapefruit) have not shown significant amounts of furanocoumarin; these studies were also conducted on eight fruit all picked at one time from one tree.[35]

Common lemons are the product of orange/citron hybridization, and hence have pomelo ancestry, and although Key limes are papeda/citron hybrids, the more commercially prevalent Persian limes and similar varieties are crosses of the Key lime with lemons, and hence likewise have pomelo ancestry.[32][33] These limes can also inhibit drug metabolism.[37] Other less-common citrus species also referred to as lemons or limes are genetically distinct from the more common varieties, with different proportions of pomelo ancestry.[32]

Inaccurate labeling

Marketing classifications often do not correspond to taxonomic ones. The "Ambersweet" cultivar is classified and sold as an orange, but does not descend from the same common ancestor as sweet oranges; it has grapefruit, orange, and mandarin ancestry. Fruits are often sold as mandarin, tangerine, or satsuma (which may be synonyms[38]). Fruit sold under these names include many that are, like Sunbursts and Murcotts, hybrids with grapefruit ancestry.[35][39][40] The diversity of fruits called limes is remarkable; some, like the Spanish lime and Wild lime, are not even citrus fruit.

In some countries, citrus fruit must be labelled with the name of a registered cultivar. Juice is often not so labelled. Some medical literature also names the cultivar tested.

Other fruit and vegetables

The discovery that flavonoids are responsible for some interactions make it plausible that other fruit and vegetables are affected.[27]

Apple juice

Apple juice, especially commercially produced products, interferes with the action of OATPs.[41] This interference can decrease the absorption of a variety of commonly used medications, including beta blockers like atenolol, antibiotics like ciprofloxacin, and antihistamines like montelukast.[41] Apple juice has been implicated in interfering with etoposide, a chemotherapy drug, and cyclosporine, taken by transplant patients to prevent rejection of their new organs.[8]

Pomegranate juice

Pomegranate juice inhibits the action of the drug metabolizing enzymes CYP2C9 and CYP3A4.[42] (As of 2014), however, the currently available literature does not appear to indicate a clinically relevant impact of pomegranate juice on drugs that are metabolized by CYP2C9 and CYP3A4.[42]

Affected drugs

Researchers have identified over 85 drugs with which grapefruit is known to have an adverse reaction.[43][1] According to a review done by the Canadian Medical Association,[1] there is an increase in the number of potential drugs that can interact with grapefruit juice, and of the number of fruit types that can interact with those drugs. From 2008 to 2012, the number of drugs known to potentially interact with grapefruit, with risk of harmful or even dangerous effects (gastrointestinal bleeding, nephrotoxicity), increased from 17 to 43.[1]

Traits

The interaction between citrus and medication depends on the individual drug, and not the class of the drug. Drugs that interact usually share three common features: they are taken orally, normally only a small amount enters systemic blood circulation, and they are metabolized by CYP3A4.[1] The effects on the CYP3A4 in the liver could in principle cause interactions with non-oral drugs,[citation needed] and non-CYP3A4-mediated effects also exist.[27]

Cytochrome isoforms affected by grapefruit components include CYP3A4, CYP1A2, CYP2C9, and CYP2D6.[20] Drugs that are metabolized by these enzymes may have interactions with components of grapefruit.

An easy way to tell if a medication may be affected by grapefruit juice is by researching whether another known CYP3A4 inhibitor drug is already contraindicated with the active drug of the medication in question. Examples of such known CYP3A4 inhibitors include cisapride (Propulsid),[44] erythromycin, itraconazole (Sporanox), ketoconazole (Nizoral), and mibefradil (Posicor).[45]

Incomplete list of affected drugs

By enzyme

Drugs that interact with grapefruit compounds at CYP3A4 include

Drugs that interact with grapefruit compounds at CYP1A2 include

Drugs that interact with grapefruit compounds at CYP2D6 include

Research has been done on the interaction between amphetamines and CYP2D6 enzyme, and researchers concluded that some parts of substrate molecules contribute to the binding of the enzyme.[57]

Other interactions

Additional drugs found to be affected by grapefruit juice include, but are not limited to

  • Some statins, including atorvastatin (Lipitor),[58] lovastatin (Mevacor), and simvastatin (Zocor, Simlup, Simcor, Simvacor)[59]
  • Anti-arrhythmics including amiodarone (Cordarone), dronedarone (Multaq), quinidine (Quinidex, Cardioquin, Quinora), disopyramide (Norpace), propafenone (Rythmol) and carvedilol (Coreg)[59]
  • Amlodipine: Grapefruit increases the available amount of the drug in the blood stream, leading to an unpredictable increase in antihypertensive effects.
  • Anti-migraine drugs ergotamine (Cafergot, Ergomar), amitriptyline (Elavil, Endep, Vanatrip) and nimodipine (Nimotop)[59]
  • Erectile dysfunction drugs sildenafil (Viagra), tadalafil (Cialis) and vardenafil (Levitra)[59][60]
  • Acetaminophen/paracetamol (Tylenol) concentrations were found to be increased in murine blood by white and pink grapefruit juice, with the white juice acting faster.[61] "The bioavailability of paracetamol was significantly reduced following multiple GFJ administration" in mice and rats. This suggests that repeated intake of grapefruit juice reduces the efficacy and bioavailability of acetaminophen/paracetamol in comparison with a single dose of grapefruit juice, which conversely increases the efficacy and bioavailability of acetaminophen/paracetamol.[62][63]
  • Anthelmintics: Used for treating certain parasitic infections; includes praziquantel
  • Buprenorphine: Metabolized into norbuprenorphine by CYP3A4[64]
  • Buspirone (Buspar): Grapefruit juice increased peak and AUC plasma concentrations of buspirone 4.3- and 9.2-fold, respectively, in a randomized, 2-phase, ten-subject crossover study.[65]
  • Codeine is a prodrug that produces its analgesic properties following metabolism to morphine entirely by CYP2D6.[66]
  • Ciclosporin (cyclosporine, Neoral): Blood levels of ciclosporin are increased if taken with grapefruit juice, orange juice, or apple juice.[8] A plausible mechanism involves the combined inhibition of enteric CYP3A4 and MDR1, which potentially leads to serious adverse events (e.g., nephrotoxicity). Blood levels of tacrolimus (Prograf) can also be equally affected for the same reason as ciclosporin, as both drugs are calcineurin inhibitors.[67]
  • Dihydropyridines including felodipine (Plendil), nicardipine (Cardene), nifedipine, nisoldipine (Sular) and nitrendipine (Bayotensin)[59]
  • Erlotinib (Tarceva)[68]
  • Exemestane, aromasin, and by extension all estrogen-like compounds and aromatase inhibitors that mimic estrogen in function will be increased in effect, causing increased estrogen retention and increased drug retention.[69]
  • Etoposide interferes with grapefruit, orange, and apple juices.[8]
  • Fexofenadine (Allegra) concentrations are decreased rather than increased as is the case with most grapefruit–drug interactions.[70][71]
  • Fluvoxamine (Luvox, Faverin, Fevarin and Dumyrox)[72]
  • Imatinib (Gleevec): Although no formal studies with imatinib and grapefruit juice have been conducted, the fact that grapefruit juice is a known inhibitor of the CYP 3A4 suggests that co-administration may lead to increased imatinib plasma concentrations. Likewise, although no formal studies were conducted, co-administration of imatinib with another specific type of citrus juice called Seville orange juice (SOJ) may lead to increased imatinib plasma concentrations via inhibition of the CYP3A isoenzymes. Seville orange juice is not usually consumed as a juice because of its sour taste, but it is found in marmalade and other jams. Seville orange juice has been reported to be a possible inhibitor of CYP3A enzymes without affecting MDR1 when taken concomitantly with ciclosporin.[73]
  • Ketamine: After drinking 200 mL of grapefruit juice daily for five days, the overall absorption of orally ingested ketamine was three-fold compared to a control group of a clinical trial. The peak blood ketamine concentration was over two-fold.[74]
  • Levothyroxine (Eltroxin, Levoxyl, Synthroid): "Grapefruit juice may slightly delay the absorption of levothyroxine, but it seems to have only a minor effect on its bioavailability."[clarification needed][75]
  • Losartan (Cozaar)[59]
  • Methadone: Inhibits the metabolism of methadone and raises serum levels.[76]
  • Omeprazole (Losec, Prilosec)[77]
  • Oxycodone: grapefruit juice enhances the exposure to oral oxycodone. And a randomized, controlled trial 12 healthy volunteers ingested 200 mL of either grapefruit juice or water three times daily for five days. On the fourth day 10 mg of oxycodone hydrochloride were administered orally. Analgesic and behavioral effects were reported for 12 hours and plasma samples were analyzed for oxycodone metabolites for 48 hours. Grapefruit juice and increased the mean area under the oxycodone concentration-time curve (AUC(0-∞)) by 1.7 fold, the peak plasma concentration by 1.5-fold and the half-life of oxycodone by 1.2-fold as compared to water. The metabolite-to-parent ratios of noroxycodone and noroxymorphone decreased by 44% and 45% respectively. Oxymorphone AUC(0-∞) increased by 1.6-fold but the metabolite-to-parent ratio remained unchanged.[78]
  • Quetiapine (Seroquel)[79]
  • Repaglinide (Prandin)[59]
  • Tamoxifen (Nolvadex): Tamoxifen is metabolized by CYP2D6 into its active metabolite 4-hydroxytamoxifen. Grapefruit juice may potentially reduce the effectiveness of tamoxifen.[80]
  • Trazodone (Desyrel): Little or no interaction with grapefruit juice.[81]
  • Verapamil (Calan SR, Covera HS, Isoptin SR, Verelan): atrioventricular conduction disorders.[59]
  • Warfarin (coumadin)[82]
  • Zolpidem (Ambien): Little or no interaction with grapefruit juice[81]
Drugs affected by grapefruit juice
Drug class Major Interactions Minor interactions
Antiarrhythmic agents amiodarone (Cordarone)
dronedarone (Multaq)
dofetilide (Tikosyn)
Antihistamines terfenadine (Seldane) (off the market)
diphenhydramine (Benadryl) (partially)
astemizole (Hismanal) (off the market)
Calcium channel antagonists felodipine (Plendil)
nicardipine (Cardene)
nifedipine (Procardia)
nimodipine (Nimotop)
nisoldipine (Sular)
isradipine (DynaCirc)
Statins (HMG-CoA reductase inhibitors) simvastatin (Zocor)
lovastatin (Mevacor)
atorvastatin (Lipitor)
cerivastatin (Baycol) (off the market)
Cough Suppressant/NMDA Antagonist dextromethorphan
Erectile dysfunction drugs sildenafil (Viagra)
tadalafil (Cialis)
vardenafil (Levitra)
HIV protease inhibitors saquinavir (Invirase)
ritonavir (Norvir)
nelfinavir (Viracept)
amprenavir (Agenerase)
Hormones ethinylestradiol (Ortho-Cept, many others)
methylprednisolone (Medrol)
Immunosuppressants ciclosporin (Sandimmune Neoral)
tacrolimus (Prograf)
sirolimus (Rapamune)
mercaptopurine
Sedatives, hypnotics, and anxiolytics buspirone (Buspar) triazolam (Halcion)
midazolam (Versed)
diazepam (Valium)
zaleplon (Sonata)
alprazolam (Xanax)

clonazepam (Klonopin)

ketamine

Other psychotropics carbamazepine (Tegretol)
trazodone (Desyrel)
quetiapine (Seroquel)
fluvoxamine (Luvox)
nefazodone (Serzone)
Other miscellaneous drugs cisapride (Prepulsid, Propulsid)[44]
ivabradine (Corlanor)[83]

References

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 Bailey, D. G.; Dresser, G.; Arnold, J. M. O. (2013). "Grapefruit-medication interactions: Forbidden fruit or avoidable consequences?". Canadian Medical Association Journal 185 (4): 309–316. doi:10.1503/cmaj.120951. PMID 23184849. 
  2. 2.0 2.1 2.2 2.3 Bailey, D.G.; Dresser, G.K.; Bend, J.R. (June 2003). "Bergamottin, lime juice, and red wine as inhibitors of cytochrome P450 3a4 activity: comparison with grapefruit juice". Clinical Pharmacology & Therapeutics 73 (6): 529–537. doi:10.1016/S0009-9236(03)00051-1. PMID 12811362. 
  3. 3.0 3.1 Gallagher, James (2012-11-26). "Grapefruit and pills mix warning". BBC News. https://www.bbc.co.uk/news/health-20497086. 
  4. 4.0 4.1 Chen, M.; Zhou, S. Y.; Fabriaga, E.; Zhang, P. H.; Zhou, Q. (April 2018). "Food–drug interactions precipitated by fruit juices other than grapefruit juice: An update review". J Food Drug Anal 26 (2S): S61–S71. doi:10.1016/j.jfda.2018.01.009. PMID 29703387. 
  5. 5.0 5.1 Bailey, D. G.; Spence, J. D.; Munoz, C.; Arnold, J. M. (1991). "Interaction of citrus juices with felodipine and nifedipine". The Lancet 337 (8736): 268–269. doi:10.1016/0140-6736(91)90872-m. PMID 1671113. 
  6. Bailey, David G.; Malcolm, J.; Arnold, O.; David Spence, J. (2002-01-04). "Grapefruit juice–drug interactions". British Journal of Clinical Pharmacology 46 (2): 101–110. doi:10.1046/j.1365-2125.1998.00764.x. PMID 9723817. 
  7. 7.0 7.1 7.2 7.3 7.4 Saito, Mitsuo; Hirata-Koizumi, Mutsuko; Matsumoto, Mariko; Urano, Tsutomu; Hasegawa, Ryuichi (2005). "Undesirable effects of citrus juice on the pharmacokinetics of drugs: focus on recent studies". Drug Safety 28 (8): 677–694. doi:10.2165/00002018-200528080-00003. PMID 16048354. 
  8. 8.0 8.1 8.2 8.3 8.4 "Fruit juice 'could affect drugs'". BBC News. 20 August 2008. http://news.bbc.co.uk/2/hi/health/7572500.stm. 
  9. "Dr. David Bailey finds new reason to avoid fruit juices when taking drugs". 20 August 2008. https://www.schulich.uwo.ca/schulichhome/articles/2008/08/20/dr-david-bailey-finds-new-reason-to-avoid-fruit-juices-when-taking-drugs.html. 
  10. 10.0 10.1 10.2 "Time course of recovery of cytochrome p450 3A function after single doses of grapefruit juice". Clinical Pharmacology and Therapeutics 74 (2): 121–9. August 2003. doi:10.1016/S0009-9236(03)00118-8. PMID 12891222. 
  11. 11.0 11.1 11.2 Mitchell, Steve (19 February 2016). "Why Grapefruit and Medication Can Be a Dangerous Mix". http://www.consumerreports.org/health/grapefruit-and-medications-can-be-a-dangerous-mix/. 
  12. Fuhr, Uwe (1998). "Drug Interactions with Grapefruit Juice: Extent, Probable Mechanism and Clinical Relevance" (in en). Drug Safety 18 (4): 251–272. doi:10.2165/00002018-199818040-00002. ISSN 0114-5916. PMID 9565737. 
  13. 13.0 13.1 13.2 13.3 13.4 13.5 Pirmohamed, Munir (12 January 2013). "Drug-grapefruit juice interactions: Two mechanisms are clear but individual responses vary". BMJ 346 (7890): 9. doi:10.1136/bmj.f1. PMID 23297175. 
  14. FDA Consumer update
  15. Fujita, Tadashi; Kawase, Atsushi; Niwa, Toshiro; Tomohiro, Norimichi; Masuda, Megumi; Matsuda, Hideaki; Iwaki, Masahiro (2008). "Comparative Evaluation of 12 Immature Citrus Fruit Extracts for the Inhibition of Cytochrome P450 Isoform Activities" (in English). Biological and Pharmaceutical Bulletin 31 (5): 925–930. doi:10.1248/bpb.31.925. PMID 18451520. 
  16. 16.0 16.1 Edwards, D. J.; Bernier, S. M. (1996). "Naringin and naringenin are not the primary CYP3A inhibitors in grapefruit juice". Life Sciences 59 (13): 1025–1030. doi:10.1016/0024-3205(96)00417-1. PMID 8809221. 
  17. "Naringin Extraction from Exhausted Bergamot Peels". Perfumer & Flavourist. 1996-09-01. http://www.perfumerflavorist.com/fragrance/application/multiuse/Naringin-Extraction-from-Exhausted-Bergamot-Peels-370010431.html. 
  18. Paine, M.F.; Widmer, W.W.; Hart, H.L.; Pusek, S.N.; Beavers, K.L.; Criss, A.B.; Brown, S.S.; Thomas, B.F. et al. (May 2006). "A furanocoumarin-free grapefruit juice establishes furanocoumarins as the mediators of the grapefruit juice-felodipine interaction". The American Journal of Clinical Nutrition 83 (5): 1097–105. doi:10.1093/ajcn/83.5.1097. PMID 16685052. http://ajcn.nutrition.org/content/83/5/1097.full.pdf+html. 
  19. Veronese ML, Gillen LP, Burke JP, Dorval EP, Hauck WW, Pequignot E, Waldman SA, Greenberg HE (Aug 2003). "Exposure-dependent inhibition of intestinal and hepatic CYP3A4 in vivo by grapefruit juice". Journal of Clinical Pharmacology 43 (8): 831–9. doi:10.1177/0091270003256059. PMID 12953340. 
  20. 20.0 20.1 "Inhibition selectivity of grapefruit juice components on human cytochromes P450". Archives of Biochemistry and Biophysics 378 (2): 356–63. June 2000. doi:10.1006/abbi.2000.1835. PMID 10860553. 
  21. "Inactivation of cytochrome P450 3A4 by bergamottin, a component of grapefruit juice". Chemical Research in Toxicology 11 (4): 252–9. April 1998. doi:10.1021/tx970192k. PMID 9548795. 
  22. "Grapefruit juice–drug interactions". British Journal of Clinical Pharmacology 46 (2): 101–10. August 1998. doi:10.1046/j.1365-2125.1998.00764.x. PMID 9723817. 
  23. "Effect of grapefruit juice on carbamazepine bioavailability in patients with epilepsy". Clinical Pharmacology and Therapeutics 64 (3): 286–8. September 1998. doi:10.1016/S0009-9236(98)90177-1. PMID 9757152. 
  24. Bressler R (November 2006). "Grapefruit juice and drug interactions. Exploring mechanisms of this interaction and potential toxicity for certain drugs". Geriatrics 61 (11): 12–8. PMID 17112309. 
  25. Pandit Introduction to Pharmaceutical Sciences
  26. "Exposure-dependent inhibition of intestinal and hepatic CYP3A4 in vivo by grapefruit juice". Journal of Clinical Pharmacology 43 (8): 831–9. August 2003. doi:10.1177/0091270003256059. PMID 12953340. 
  27. 27.0 27.1 27.2 27.3 Bailey, David G. (November 2010). "Fruit juice inhibition of uptake transport: a new type of food–drug interaction". British Journal of Clinical Pharmacology 70 (5): 645–655. doi:10.1111/j.1365-2125.2010.03722.x. PMID 21039758. 
  28. "Relationship between time of intake of grapefruit juice and its effect on pharmacokinetics and pharmacodynamics of felodipine in healthy subjects". European Journal of Clinical Pharmacology 49 (1–2): 61–7. 1995. doi:10.1007/BF00192360. PMID 8751023. 
  29. 29.0 29.1 Greenblatt, DJ; Patki, KC; von Moltke, LL; Shader, RI (2001). "Drug interactions with grapefruit juice: an update". J Clin Psychopharmacol 21 (4): 357–9. doi:10.1097/00004714-200108000-00001. PMID 11476118. 
  30. 30.0 30.1 Chen, Chunxian; Yu, Qibin; Wei, Xu; Cancalon, Paul F.; Gmitter Jr., Fred G.; Belzile, F. (October 2014). "Identification of genes associated with low furanocoumarin content in grapefruit". Genome 57 (10): 537–545. doi:10.1139/gen-2014-0164. PMID 25756876. 
  31. "Important considerations for grapefruit and drug interaction". https://www.healio.com/cardiology/chd-prevention/news/print/cardiology-today/%7B0c787159-ae5e-4b46-8777-080e952ff84c%7D/important-considerations-for-grapefruit-and-drug-interaction. 
  32. 32.0 32.1 32.2 32.3 Curk, Franck; Ollitrault, Frédérique; Garcia-Lor, Andres; Luro, François; Navarro, Luis; Ollitrault, Patrick (2016). "Phylogenetic origin of limes and lemons revealed by cytoplasmic and nuclear markers". Annals of Botany 11 (4): 565–583. doi:10.1093/aob/mcw005. PMID 26944784. 
  33. 33.0 33.1 33.2 33.3 Wu, Guohong Albert; Terol, Javier; Ibanez, Victoria; López-García, Antonio; Pérez-Román, Estela; Borredá, Carles; Domingo, Concha; Tadeo, Francisco R et al. (2018). "Genomics of the origin and evolution of Citrus". Nature 554 (7692): 311–316. doi:10.1038/nature25447. PMID 29414943. Bibcode2018Natur.554..311W. 
  34. 34.0 34.1 Curk, Franck; Ancillo, Gema; Garcia-Lor, Andres; Luro, François; Perrier, Xavier; Jacquemoud-Collet, Jean-Pierre; Navarro, Luis; Ollitrault, Patrick (December 2014). "Next generation haplotyping to decipher nuclear genomic interspecific admixture in Citrusspecies: analysis of chromosome 2". BMC Genetics 15 (1): 152. doi:10.1186/s12863-014-0152-1. PMID 25544367. 
  35. 35.0 35.1 35.2 35.3 Widmer, Wilbur (31 May 2006). "One Tangerine/Grapefruit Hybrid (Tangelo) Contains Trace Amounts of Furanocoumarins at a Level Too Low To Be Associated with Grapefruit/Drug Interactions". Journal of Food Science 70 (6): c419–c422. doi:10.1111/j.1365-2621.2005.tb11440.x. http://naldc.nal.usda.gov/download/1759/PDF. 
  36. "Hybrid grapefruit safe for prescription meds". Futurity.org. 2011-10-25. https://www.futurity.org/hybrid-grapefruit-safe-for-prescription-meds/. 
  37. 37.0 37.1 Bakalar, Nicholas (2006-03-21). "Experts Reveal the Secret Powers of Grapefruit Juice". The New York Times: p. F6. https://www.nytimes.com/2006/03/21/health/21grap.html?ex=1300597200&en=61e8347bdb9afac9&ei=5088&partner=rssnyt&emc=rss. 
  38. "Synonymy of C. reticulata at The Plant List". http://www.theplantlist.org/tpl1.1/record/kew-2724336. 
  39. Larry K. Jackson and Stephen H. Futch (2018-07-10). "Robinson Tangerine". ufl.edu. http://edis.ifas.ufl.edu/ch073. 
  40. Commernet, 2011. "20-13.0061. Sunburst Tangerines; Classification and Standards, 20-13. Market Classification, Maturity Standards And Processing Or Packing Restrictions For Hybrids, D20. Departmental, 20. Department of Citrus, Florida Administrative Code". State of Florida. http://florida.eregulations.us/fac/20-13.0061/. 
  41. 41.0 41.1 Andrade, Chittaranjan (24 November 2014). "Fruit Juice, Organic Anion Transporting Polypeptides, and Drug Interactions in Psychiatry". The Journal of Clinical Psychiatry 75 (11): e1323–e1325. doi:10.4088/JCP.14f09572. PMID 25470100. 
  42. 42.0 42.1 Andrade, Chittaranjan (15 April 2014). "Potentially Significant Versus Clinically Significant Drug Interactions: Pomegranate Juice as a Case in Point". The Journal of Clinical Psychiatry 75 (4): e292–e293. doi:10.4088/JCP.14f09112. PMID 24813412. 
  43. Rabin, Roni Caryn (17 December 2012). "Grapefruit Is a Culprit in More Drug Reactions". The New York Times. http://well.blogs.nytimes.com/2012/12/17/grapefruit-is-a-culprit-in-more-drug-reactions/. 
  44. 44.0 44.1 "Influence of grapefruit juice on cisapride pharmacokinetics". Clinical Pharmacology and Therapeutics 65 (4): 395–401. April 1999. doi:10.1016/S0009-9236(99)70133-5. PMID 10223776. 
  45. "Wake Forest Baptist Medical Center". wakehealth.edu. http://www.wakehealth.edu/uploadedFiles/User_Content/Research/Institutes_and_Centers/CCOP_Research_Base/Protocols/98213/Appendices/Appendix%207%20%20Medication%20Reference%20List%20Am%206%2010.14.14(1).pdf. 
  46. Musmul, A.; Cingi, M. Ipek; Boydaĝ, B. S.; Aktan, Yasemın; Özdemir, Murat (1998). "Interaction between grapefruit juice and diazepam in humans" (in en). European Journal of Drug Metabolism and Pharmacokinetics 23 (1): 55–59. doi:10.1007/BF03189827. PMID 9625273. 
  47. "Drug Interactions Checker - Medscape Drug Reference Database". https://reference.medscape.com/drug-interactionchecker. 
  48. Tanaka, E. (October 1999). "Clinically significant pharmacokinetic drug interactions with benzodiazepines". Journal of Clinical Pharmacy and Therapeutics 24 (5): 347–355. doi:10.1046/j.1365-2710.1999.00247.x. ISSN 0269-4727. PMID 10583697. 
  49. "Interaction between grapefruit juice and hypnotic drugs: comparison of triazolam and quazepam". European Journal of Clinical Pharmacology 62 (3): 209–15. March 2006. doi:10.1007/s00228-005-0071-1. PMID 16416305. 
  50. "Ritonavir (Norvir)". HIV InSite. UCSF. 2006-10-18. http://hivinsite.ucsf.edu/InSite?page=ar-03-02. [failed verification]
  51. "The effects of grapefruit juice on sertraline metabolism: an in vitro and in vivo study". Clinical Therapeutics 21 (11): 1890–9. November 1999. doi:10.1016/S0149-2918(00)86737-5. PMID 10890261. 
  52. Pillai, Unnikrishnan; Muzaffar, Jameel; Sen, Sandeep; Yancey, Abigail (2009). "Grapefruit Juice and Verapamil: A Toxic Cocktail". Southern Medical Journal 102 (3): 308–309. doi:10.1097/smj.0b013e3181928f81. PMID 19204629. http://www.medscape.com/viewarticle/589497. Retrieved 2017-01-22. 
  53. Fuhr, Uwe (1998). "Drug Interactions with Grapefruit Juice". Drug Safety 18 (4): 251–272. doi:10.2165/00002018-199818040-00002. PMID 9565737. 
  54. "Interactions of amphetamine analogs with human liver CYP2D6". Biochemical Pharmacology 53 (11): 1605–12. June 1997. doi:10.1016/S0006-2952(97)00014-2. PMID 9264312. 
  55. "SuperCYP: a comprehensive database on Cytochrome P450 enzymes including a tool for analysis of CYP–drug interactions". Nucleic Acids Research 38 (Database issue): D237–43. January 2010. doi:10.1093/nar/gkp970. PMID 19934256. 
  56. "HIV gp120- and methamphetamine-mediated oxidative stress induces astrocyte apoptosis via cytochrome P450 2E1". Cell Death & Disease 4 (10): e850. 2013. doi:10.1038/cddis.2013.374. PMID 24113184. 
  57. "Metabolism/ Metabolites of amphetamines interacting with The Cytochrome P450 CYP2D6 enzyme". U.S. National Library of Medicine. http://toxnet.nlm.nih.gov/cgi-bin/sis/search2/r?dbs+hsdb:@term+@rn+300-62-9. [verification needed]
  58. 58.0 58.1 "Grapefruit juice increases serum concentrations of atorvastatin and has no effect on pravastatin". Clinical Pharmacology and Therapeutics 66 (2): 118–27. August 1999. doi:10.1053/cp.1999.v66.100453001. PMID 10460065. 
  59. 59.0 59.1 59.2 59.3 59.4 59.5 59.6 59.7 59.8 "Interactions between grapefruit juice and cardiovascular drugs". American Journal of Cardiovascular Drugs 4 (5): 281–97. 2004. doi:10.2165/00129784-200404050-00002. PMID 15449971. 
  60. "Effects of grapefruit juice on the pharmacokinetics of sildenafil". Clinical Pharmacology and Therapeutics 71 (1): 21–9. January 2002. doi:10.1067/mcp.2002.121236. PMID 11823754. 
  61. "Interaction of white and pink grapefruit juice with acetaminophen (paracetamol) in vivo in mice". Journal of Medicinal Food 11 (4): 795–8. December 2008. doi:10.1089/jmf.2008.0059. PMID 19053875. 
  62. Qinna, Nidal A.; Ismail, Obbei A.; Alhussainy, Tawfiq M.; Idkaidek, Nasir M.; Arafat, Tawfiq A. (2016-04-01). "Evidence of reduced oral bioavailability of paracetamol in rats following multiple ingestion of grapefruit juice". European Journal of Drug Metabolism and Pharmacokinetics 41 (2): 187–195. doi:10.1007/s13318-014-0251-4. PMID 25547640. 
  63. Samojlik, I.; Rasković, A.; Daković-Svajcer, K.; Mikov, M.; Jakovljević, V. (1999-07-01). "The effect of paracetamol on peritoneal reflex after single and multiple grapefruit ingestion". Experimental and Toxicologic Pathology 51 (4–5): 418–420. doi:10.1016/S0940-2993(99)80032-3. PMID 10445408. 
  64. "Buprenorphine: clinical pharmacokinetics in the treatment of opioid dependence". Clinical Pharmacokinetics 44 (7): 661–80. 2005. doi:10.2165/00003088-200544070-00001. PMID 15966752. 
  65. "Grapefruit juice substantially increases plasma concentrations of buspirone". Clinical Pharmacology and Therapeutics 64 (6): 655–60. December 1998. doi:10.1016/S0009-9236(98)90056-X. PMID 9871430. 
  66. Smith, Howard S. (2009-07-01). "Opioid Metabolism". Mayo Clinic Proceedings 84 (7): 613–624. doi:10.4065/84.7.613. PMID 19567715. 
  67. "Further characterization of a furanocoumarin-free grapefruit juice on drug disposition: studies with cyclosporine". The American Journal of Clinical Nutrition 87 (4): 863–71. April 2008. doi:10.1093/ajcn/87.4.863. PMID 18400708. http://ajcn.nutrition.org/content/87/4/863.full.pdf+html. 
  68. "HIGHLIGHTS OF PRESCRIBING INFORMATION". Gene. http://www.gene.com/gene/products/information/pdf/tarceva-prescribing.pdf. 
  69. "Exemestane (Aromasin)". 1 September 2014. http://www.macmillan.org.uk/Cancerinformation/Cancertreatment/Treatmenttypes/Hormonaltherapies/Individualhormonaltherapies/Exemestane.aspx. 
  70. "Effect of grapefruit juice volume on the reduction of fexofenadine bioavailability: possible role of organic anion transporting polypeptides". Clinical Pharmacology and Therapeutics 77 (3): 170–7. March 2005. doi:10.1016/j.clpt.2004.10.005. PMID 15735611. 
  71. Yael Waknine (1 January 2007). "FDA Safety Changes: Allegra, Cymbalta, Concerta". Medscape Medical News. http://www.medscape.org/viewarticle/550192. 
  72. "Grapefruit juice-fluvoxamine interaction--is it risky or not?". Journal of Clinical Psychopharmacology 23 (4): 422–4. August 2003. doi:10.1097/01.jcp.0000085423.74359.f2. PMID 12920426. 
  73. Jhaveri, Limca. "Novartis Answers About Gleevec". http://www.gistsupport.org/treatments-for-gist/gleevec/novartis-answers-about-gleevec.php. 
  74. Peltoniemi, Marko A.; Saari, Teijo I.; Hagelberg, Nora M.; Laine, Kari; Neuvonen, Pertti J.; Olkkola, Klaus T. (June 2012). "S-ketamine concentrations are greatly increased by grapefruit juice". European Journal of Clinical Pharmacology 68 (6): 979–986. doi:10.1007/s00228-012-1214-9. ISSN 1432-1041. PMID 22286159. 
  75. "Effects of grapefruit juice on the absorption of levothyroxine". British Journal of Clinical Pharmacology 60 (3): 337–41. September 2005. doi:10.1111/j.1365-2125.2005.02433.x. PMID 16120075. 
  76. "Effects of grapefruit juice on the pharmacokinetics of the enantiomers of methadone". Clinical Pharmacology and Therapeutics 76 (1): 55–63. July 2004. doi:10.1016/j.clpt.2004.03.007. PMID 15229464. 
  77. "Effect of grapefruit juice on the disposition of omeprazole". British Journal of Clinical Pharmacology 52 (2): 216–7. August 2001. doi:10.1111/j.1365-2125.1978.00999.pp.x. PMID 11488783. 
  78. Nieminen, Tuija H.; Hagelberg, Nora M.; Saari, Teijo I.; Neuvonen, Mikko; Neuvonen, Pertti J.; Laine, Kari; Olkkola, Klaus T. (2010-10-01). "Grapefruit juice enhances the exposure to oral oxycodone". Basic & Clinical Pharmacology & Toxicology 107 (4): 782–788. doi:10.1111/j.1742-7843.2010.00582.x. PMID 20406214. 
  79. "Grapefruit Interactions". healthCentral. http://www.healthcentral.com/peoplespharmacy/pp_guides/PDF/gfruit02.pdf. 
  80. "CYP2D6 polymorphisms and the impact on tamoxifen therapy". Journal of Pharmaceutical Sciences 96 (9): 2224–31. Sep 2007. doi:10.1002/jps.20892. PMID 17518364. 
  81. 81.0 81.1 "Grapefruit and medication: A cautionary note". Harvard Medical School Family Health Guide. February 2006. https://www.health.harvard.edu/fhg/updates/update0206d.shtml. 
  82. Jellin J.M., et al. Pharmacist's Letter/Prescriber's Letter of Natural Medicines Comprehensive Database. 7th ed. Stockton, CA: Therapeutic Research Faculty. 2005. 626-629
  83. "Corlanor (ivabradine) dose, indications, adverse effects, interactions...". http://www.pdr.net/drug-summary/Corlanor-ivabradine-3713.