Terbutaline

Terbutaline
Clinical data

Terbutaline (top), and (R)-(−)-terbutaline (bottom)
AHFS/Drugs.com	Monograph
MedlinePlus	a682144
Pregnancy category	C
Routes of administration	Oral (tablets, oral solution), inhalational (DPI, nebulizer solution), SQ
ATC code	R03AC03 (WHO) R03CC03 (WHO)
Legal status
Legal status	UK: POM (Prescription only)
Pharmacokinetic data
Protein binding	25%
Metabolism	GI tract (oral), liver; CYP450: unknown
Biological half-life	11-16 hours
Excretion	urine 90% (60% unchanged), bile/faeces
Identifiers
IUPAC name (RS)-5-[2-(tert-butylamino)-1-hydroxyethyl]benzene-1,3-diol
CAS Number	23031-25-6^Y
PubChem (CID)	5403
IUPHAR/BPS	560
DrugBank	DB00871^Y
ChemSpider	5210^Y
UNII	N8ONU3L3PG^Y
KEGG	D08570^Y
ChEBI	CHEBI:9449^N
ChEMBL	CHEMBL1760^Y
ECHA InfoCard	100.041.244
Chemical and physical data
Formula	C₁₂H₁₉NO₃
Molar mass	225.284 g/mol
3D model (Jmol)	Interactive image
Chirality	Racemic mixture
SMILES Oc1cc(cc(O)c1)C(O)CNC(C)(C)C
InChI InChI=1S/C12H19NO3/c1-12(2,3)13-7-11(16)8-4-9(14)6-10(15)5-8/h4-6,11,13-16H,7H2,1-3H3^Y Key:XWTYSIMOBUGWOL-UHFFFAOYSA-N^Y
^NY (what is this?) (verify)

Terbutaline (trade names "Bronclyn",Brethine, Bricanyl, Brethaire, or Terbulin) 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 has ordered to put a boxed 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 internal heart problems and death."^[2]^[3]

The American College of Obstetricians and Gynecologists also discourages the use of terbutaline for preventing preterm labor.

Terbutaline is currently 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.

Uses

Terbutaline is used as a fast-acting bronchodilator (often used as a short-term asthma treatment) and as a tocolytic^[4] to delay premature labor. The inhaled form of terbutaline starts working within 15 minutes and can last up to 6 hours.

Terbutaline as a treatment for premature labor is an off-label use not approved by the FDA. It is a pregnancy category C medication and is routinely prescribed to stop contractions. After successful intravenous tocolysis, little evidence exists that oral terbutaline is effective.^[5] However, following uterine inversion in the third stage of labor, terbutaline (or either Halothane or magnesium sulfate) can be used to relax the uterus if necessary prior to uterine replacement.

Structure activity relationships

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.^[6]

Side effects

Adult — tachycardia, anxiety, nervousness, tremors, headache, hyperglycemia, hypokalemia, hypotension and, rarely, pulmonary edema.^[7]
Fetal — tachycardia and hypoglycemia.^[8]

Chemistry

It is synthesized by brominating 3,5-dibenzyloxyacetophenone into the appropriate 3,5-dibenzyloxybromoacetophenone, which is reacted with N-benzyl-N-tert-butylamine, giving the aminoketone. Reduction of this product by hydrogen over a palladium catalyst leads to terbutaline.^[9]^[10]^[11]

References

↑ WHO. "Antenatal administration of corticosteroids for women at risk of preterm birth". WHO. Retrieved 2013-03-25.
↑ "Most Popular E-mail Newsletter". USA Today. 18 February 2011.
↑ http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm243840.htm
↑ 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". Int J Gynaecol Obstet. 102 (3): 263–6. doi:10.1016/j.ijgo.2008.04.010. PMID 18554601.
↑ Goldenberg, RL (November 2002). "High-Risk Pregnancy Series: An Expert's View". Obstetrics & Gynecology. 100 (5): 1020–1037. doi:10.1016/S0029-7844(02)02212-3.
↑ Medicinal Chemistry of Adrenergics and Cholinergics
↑ Shen, Howard (2008). Illustrated Pharmacology Memory Cards: PharMnemonics. Minireview. p. 7. ISBN 1-59541-101-1.
↑ , 5 Minute Consult (Original Source: UpToDate "Terbutaline: Drug information").
↑ Draco Lunds Farmacevtiska Aktiebolag, GB 1199630 (1967)
↑ Draco Lunds Farmacevtiska Aktiebolag, BE 704932 (1968)
↑ A. L. Swensson, I. K. Weterlin, U.S. Patent 3,937,838 (1976)

Drugs for obstructive airway diseases: asthma/COPD (R03)

Adrenergics, inhalants

Short-acting β₂ agonists	Bitolterol Carbuterol Fenoterol Isoetarine Pirbuterol Procaterol Reproterol Rimiterol Salbutamol (albuterol)^#/Levosalbutamol (levalbuterol) Terbutaline Tulobuterol

Long-acting β₂ agonists	Bambuterol Clenbuterol Formoterol/Arformoterol Salmeterol Salmefamol

Ultra-long-acting β₂ agonists	Abediterol Carmoterol Indacaterol Olodaterol Vilanterol

Other	Epinephrine^# Hexoprenaline Isoprenaline (isoproterenol) Orciprenaline (metaproterenol)

Glucocorticoids

Anticholinergics/
muscarinic antagonist

Mast cell stabilizers

Xanthines

Eicosanoid inhibition

Leukotriene antagonists	Montelukast Pranlukast Zafirlukast

Arachidonate 5-lipoxygenase inhibitors	Zileuton

Thromboxane receptor antagonists	Ramatroban Seratrodast

Non-xanthine PDE4 inhibitors	Ibudilast Roflumilast

Others/unknown

Combination products

^#WHO-EM
^‡Withdrawn from market
Clinical trials:
- ^†Phase III
- ^§Never to phase III

Tocolytics/labor repressants (G02CA)

β₂ adrenoreceptor agonists	Buphenine Fenoterol Hexoprenaline Ritodrine Terbutaline

Oxytocin antagonists	Atosiban

NSAIDs	Indometacin

Calcium channel blockers	Nifedipine

Myosin inhibitors	Magnesium sulfate

Adrenergic receptor modulators

α₁

Agonists 6-FNE Amidephrine Anisodine Buspirone Cirazoline Corbadrine Dexisometheptene Dipivefrine Dopamine Droxidopa (L-DOPS) Ephedrine Epinephrine Etilefrine Etilevodopa Ethylnorepinephrine Indanidine Isometheptene L-DOPA (levodopa) L-Phenylalanine L-Tyrosine Melevodopa Metaraminol Methoxamine Methyldopa Midodrine Naphazoline Norepinephrine Octopamine (drug) Oxymetazoline Phenylephrine Phenylpropanolamine Pseudoephedrine Synephrine Tetryzoline Tiamenidine XP21279 Xylometazoline

Antagonists Abanoquil Adimolol Ajmalicine Alfuzosin Amosulalol Anisodamine Arotinolol Atiprosin Atypical antipsychotics (e.g., clozapine, olanzapine, quetiapine, risperidone) Benoxathian Buflomedil Bunazosin Carvedilol Corynanthine Dapiprazole Domesticine Doxazosin Ergolines (e.g., ergotamine, dihydroergotamine, lisuride, terguride) Etoperidone Eugenodilol Fenspiride Hydroxyzine Indoramin Ketanserin L-765,314 Labetalol mCPP Mepiprazole Metazosin Monatepil Moxisylyte Naftopidil Nantenine Nefazodone Neldazosin Niaprazine Nicergoline Niguldipine Pardoprunox Pelanserin Phendioxan Phenoxybenzamine Phentolamine Piperoxan Prazosin Quinazosin Ritanserin Silodosin Spiperone Talipexole Tamsulosin Terazosin Tiodazosin Tolazoline Trazodone Tetracyclic antidepressants (e.g., amoxapine, maprotiline, mianserin) Tricyclic antidepressants (e.g., amitriptyline, clomipramine, doxepin, imipramine, trimipramine) Trimazosin Typical antipsychotics (e.g., chlorpromazine, fluphenazine, loxapine, thioridazine) Urapidil WB-4101 Zolertine

α₂

Agonists (R)-3-Nitrobiphenyline 4-NEMD 6-FNE Amitraz Apraclonidine Brimonidine Cannabivarin Clonidine Corbadrine Detomidine Dexmedetomidine Dihydroergotamine Dipivefrine Dopamine Droxidopa (L-DOPS) Etilevodopa Ephedrine Ergotamine Epinephrine Etilefrine Ethylnorepinephrine Guanabenz Guanfacine Guanoxabenz L-DOPA (levodopa) L-Phenylalanine L-Tyrosine Lofexidine Medetomidine Melevodopa Methyldopa Mivazerol Naphazoline Norepinephrine Oxymetazoline Phenylpropanolamine Piperoxan Pseudoephedrine Rilmenidine Romifidine Talipexole Tetrahydrozoline Tiamenidine Tizanidine Tolonidine Urapidil XP21279 Xylazine Xylometazoline

Antagonists 1-PP Adimolol Aptazapine Atipamezole Atypical antipsychotics (e.g., asenapine, clozapine, lurasidone, paliperidone, quetiapine, risperidone, zotepine) Azapirones (e.g., buspirone, tandospirone) BRL-44408 Buflomedil Cirazoline Efaroxan Esmirtazapine Fenmetozole Fluparoxan Idazoxan mCPP Mianserin Mirtazapine NAN-190 Olanzapine Pardoprunox Phentolamine Phenoxybenzamine Piperoxan Piribedil Rauwolscine Rotigotine SB-269970 Setiptiline Spiroxatrine Sunepitron Tolazoline Typical antipsychotics (e.g., chlorpromazine, fluphenazine, loxapine, thioridazine) Yohimbine

Agonists Abediterol Alifedrine Amibegron Arbutamine Arformoterol Arotinolol BAAM Bambuterol Befunolol Bitolterol Broxaterol Buphenine Carbuterol Carmoterol Cimaterol Clenbuterol Corbadrine Denopamine Dipivefrine Dobutamine Dopamine Dopexamine Droxidopa (L-DOPS) Ephedrine Epinephrine Etafedrine Etilefrine Etilevodopa Ethylnorepinephrine Fenoterol Formoterol Hexoprenaline Higenamine Indacaterol Isoetarine Isoprenaline Isoxsuprine L-DOPA (levodopa) L-Phenylalanine L-Tyrosine Levosalbutamol Mabuterol Melevodopa Methoxyphenamine Methyldopa Mirabegron Norepinephrine Orciprenaline Oxyfedrine PF-610355 Phenylpropanolamine Pirbuterol Prenalterol Ractopamine Procaterol Pseudoephedrine Reproterol Rimiterol Ritodrine Salbutamol Salmeterol Solabegron Terbutaline Tretoquinol Tulobuterol Vilanterol Xamoterol XP21279 Zilpaterol Zinterol

Antagonists Acebutolol Adaprolol Adimolol Afurolol Alprenolol Alprenoxime Amosulalol Ancarolol Arnolol Arotinolol Atenolol Befunolol Betaxolol Bevantolol Bisoprolol Bopindolol Bornaprolol Brefonalol Bucindolol Bucumolol Bufetolol Bufuralol Bunitrolol Bunolol Bupranolol Butaxamine Butidrine Butofilolol Capsinolol Carazolol Carpindolol Carteolol Carvedilol Celiprolol Cetamolol Cicloprolol Cinamolol Cloranolol Cyanopindolol Dalbraminol Dexpropranolol Diacetolol Dichloroisoprenaline Dihydroalprenolol Dilevalol Diprafenone Draquinolol Ecastolol Epanolol Ericolol Ersentilide Esatenolol Esprolol Eugenodilol Exaprolol Falintolol Flestolol Flusoxolol Hydroxycarteolol Hydroxytertatolol ICI-118,551 Idropranolol Indenolol Indopanolol Iodocyanopindolol Iprocrolol Isoxaprolol Isamoltane Labetalol Landiolol Levobetaxolol Levobunolol Levomoprolol Medroxalol Mepindolol Metipranolol Metoprolol Moprolol Nadolol Nadoxolol Nebivolol Nifenalol Nipradilol Oxprenolol Pacrinolol Pafenolol Pamatolol Pargolol Penbutolol Pindolol Practolol Primidolol Procinolol Pronethalol Propafenone Propranolol Ridazolol Ronactolol Soquinolol Sotalol Spirendolol SR 59230A Sulfinalol Talinolol Tazolol Tertatolol Tienoxolol Tilisolol Timolol Tiprenolol Tolamolol Toliprolol Xibenolol Xipranolol

See also: Dopaminergics

Melatonergics

Serotonergics

Monoamine reuptake and release modulators

Monoamine metabolism modulators

Monoamine neurotoxins

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