Terbutaline, sold under the brand namesBricanyl andMarex among others, is aβ2 adrenergic receptor agonist, used as a "reliever" inhaler in the management ofasthma symptoms and as atocolytic (anti-contraction medication) to delaypreterm 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, theFood 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]
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 withguaifenesin).
Terbutaline is apregnancy 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 anoff-label use not approved by the USFDA, 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]
The tertiary butyl group in terbutaline makes it more selective forβ2 receptors. Since there is no hydroxy group on position 4 of the benzene ring, the molecule is less susceptible to metabolism by the enzymecatechol-O-methyl transferase.[11]
Terbutaline is synthesized by brominating 3,5-dibenzyloxyacetophenone into 3,5-dibenzyloxybromoacetophenone, which is reacted withN-benzyl-N-tert-butylamine, giving a ketone intermediate. Reduction of this product with H₂ overPd/C leads to terbutaline.[12][13][14]
As with all β2-adrenergic receptor agonists, terbutaline is on theWorld Anti-Doping Agency's list of prohibited drugs, except when administered by inhalation and a Therapeutic Use Exemption (TUE) has been obtained in advance.
^World Health Organization (2021).World Health Organization model list of essential medicines: 22nd list (2021). Geneva: World Health Organization.hdl:10665/345533. WHO/MHP/HPS/EML/2021.02.
^Mohamed Ismail NA, Ibrahim M, Mohd Naim N, Mahdy ZA, Jamil MA, Mohd Razi ZR (September 2008). "Nifedipine versus terbutaline for tocolysis in external cephalic version".International Journal of Gynaecology and Obstetrics.102 (3):263–266.doi:10.1016/j.ijgo.2008.04.010.PMID18554601.S2CID20258298.
^GB 1199630, "Phenylethanolamine Derivatives Effective in the Treatment of Bronchospastic Conditions", issued 1967, assigned to Draco Lunds Farmacevtiska Aktiebolag
N
Y (what is this?) (verify)
-Terbutalin_Structural_Formula_V1.svg)
-Terbutalin_Structural_Formula_V1.svg)