Chemistry:Terbutaline
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 Terbutaline (top), and (R)-(−)-terbutaline (bottom) | |
| Clinical data | |
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| AHFS/Drugs.com | Monograph |
| MedlinePlus | a682144 |
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| Routes of administration | Oral (tablets, oral solution), inhalational (DPI, nebulizer solution), SQ |
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| Pharmacokinetic data | |
| Protein binding | 25% |
| Metabolism | GI tract (oral), liver; CYP450: unknown |
| Elimination half-life | 11–16 hours |
| Excretion | urine 90% (60% unchanged), bile/faeces |
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| CAS Number | |
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| Chemical and physical data | |
| Formula | C12H19NO3 |
| Molar mass | 225.288 g·mol−1 |
| 3D model (JSmol) | |
| Chirality | Racemic mixture |
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Terbutaline, sold under the brand names Bricanyl and Marex among others, is a β2 adrenergic receptor agonist, used as a "reliever" inhaler in the management of asthma symptoms and as a tocolytic (anti-contraction medication) to delay preterm labor for up to 48 hours. This time can then be used to administer steroid injections to the mother which help fetal lung maturity and reduce complications of prematurity.[1] It should not be used to prevent preterm labor or delay labor more than 48–72 hours. In February 2011, the Food and Drug Administration began requiring a black box warning on the drug's label. Pregnant women should not be given injections of the drug terbutaline for the prevention of preterm labor or for long-term (beyond 48–72 hours) management of preterm labor, and should not be given oral terbutaline for any type of prevention or treatment of preterm labor "due to the potential for serious maternal heart problems and death."[2][3]
It was patented in 1966 and came into medical use in 1970.[4] It is on the World Health Organization's List of Essential Medicines.[5]
Medical uses
Terbutaline is used as a fast-acting bronchodilator (often used as a short-term asthma treatment) and as a tocolytic[6] to delay premature labor.
As an asthma treatment, the inhaled form of terbutaline, starts working within 15 minutes and can last up to 6 hours. It is also sold as an injectable solution, an oral tablet, and as a syrup (in combination with guaifenesin).
Terbutaline is a pregnancy category C medication and is prescribed to stop contractions. After successful intravenous tocolysis, little evidence exists that oral terbutaline is effective.[7] Terbutaline as a treatment for premature labor is an off-label use not approved by the US FDA, who have warned that oral terbutaline is not effective and can cause severe heart problems or death, and while injectable terbutaline can be used for premature labor in emergency situations in a hospital setting, it should only be used for short periods of time.[8]
Side effects
- Adult — tachycardia, anxiety, nervousness, tremors, headache, hyperglycemia, hypokalemia, hypotension and, rarely, pulmonary edema.[9]
- Fetal — tachycardia and hypoglycemia.[10]
Pharmacology
The tertiary butyl group in terbutaline makes it more selective for β2 receptors. Since there is no hydroxy group on position 4 of the benzene ring, the molecule is less susceptible to metabolism by the enzyme catechol-O-methyl transferase.[11]
Chemistry
Terbutaline is synthesized by brominating 3,5-dibenzyloxyacetophenone into 3,5-dibenzyloxybromoacetophenone, which is reacted with N-benzyl-N-tert-butylamine, giving a ketone intermediate. Reduction of this product with H₂ over Pd/C leads to terbutaline.[12][13][14]
Stereochemistry
Terbutaline contains a stereocenter and consists of two enantiomers. This is a racemate, ie a 1: 1 mixture of (R) - and the (S) - form:[15]
| Enantiomers of terbutaline | |
|---|---|
-Terbutalin_Structural_Formula_V1.svg) (R)-Terbutaline |
-Terbutalin_Structural_Formula_V1.svg) (S)-Terbutaline |
Society and culture
Athletics
As with all β2-adrenergic receptor agonists, terbutaline is on the World Anti-Doping Agency's list of prohibited drugs, except when administered by inhalation and a Therapeutic Use Exemption (TUE) has been obtained in advance.
Brand names
Brand names include Bronclyn, Brethine, Bricanyl, Brethaire, Marex, and Terbulin.
References
- ↑ WHO. "Antenatal administration of corticosteroids for women at risk of preterm birth". WHO. http://apps.who.int/rhl/pregnancy_childbirth/complications/preterm_birth/cd004454_hofmeyrgj_com/en/index.html.
- ↑ "Most Popular E-mail Newsletter". USA Today. 18 February 2011. http://yourlife.usatoday.com/parenting-family/pregnancy/story/2011/02/FDA-flags-risks-on-popular-drug-used-during-pregnancy/43875986/1?csp=34news.[yes|permanent dead link|dead link}}]
- ↑ "FDA warns against certain uses of asthma drug terbutaline for preterm labor". https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm243840.htm.
- ↑ (in en) Analogue-based Drug Discovery. John Wiley & Sons. 2006. p. 542. ISBN 9783527607495. https://books.google.com/books?id=FjKfqkaKkAAC&pg=PA542.
- ↑ World Health Organization model list of essential medicines: 22nd list (2021). Geneva: World Health Organization. 2021. WHO/MHP/HPS/EML/2021.02.
- ↑ "Nifedipine versus terbutaline for tocolysis in external cephalic version". International Journal of Gynaecology and Obstetrics 102 (3): 263–266. September 2008. doi:10.1016/j.ijgo.2008.04.010. PMID 18554601.
- ↑ "The management of preterm labor". Obstetrics and Gynecology 100 (5 Pt 1): 1020–1037. November 2002. doi:10.1016/S0029-7844(02)02212-3. PMID 12423870. http://www.acog.org/from_home/publications/green_journal/2002/ong13732fla.htm.
- ↑ "FDA Drug Safety Communication: New warnings against use of terbutaline to treat preterm labor" (in en). FDA. 17 February 2011. https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-new-warnings-against-use-terbutaline-treat-preterm-labor.
- ↑ Illustrated Pharmacology Memory Cards: PharMnemonics. Minireview. 2008. p. 7. ISBN 978-1-59541-101-3.
- ↑ "Terbutaline: Drug information". Original Source: UpToDate. http://5minuteconsult.com/printDrugMonograph.aspx?MonoId=3764085.
- ↑ "Medicinal Chemistry of the Peripheral Nervous System–Adrenergics and Cholinergics their Biosynthesis, Metabolism, and Structure Activity Relationships". PharmaXChange. 1992. pp. 503–507. http://pharmaxchange.info/notes/medicinal_chemistry/adrenergics_cholinergics.html.
- ↑ "Phenylethanolamine Derivatives Effective in the Treatment of Bronchospastic Conditions" GB patent 1199630, issued 1967, assigned to Draco Lunds Farmacevtiska Aktiebolag
- ↑ "1-3,5-dihydroxyphenyl-2-alkylaminoethanols" BE patent 704932, issued 1968
- ↑ Svensson LA, Wetterlin ID, "Orally Active Bronchospasmolytic Compounds and Their Preparation", US patent 3937838, issued 1976
- ↑ Hagers Handbuch der Pharmazeutischen Praxis Band 9: Stoffe P-Z. 5. Berlin: Springer Verlag. 2014. p. 804. ISBN 978-3-642-63389-8.
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