Terbutaline

Structural formula
	Structural formula without stereochemistry
General
Non-proprietary name	Terbutaline
other names	( RS ) -2- tert -Butylamino-1- (3,5-dihydroxyphenyl) ethanol; (±) -2- tert -Butylamino-1- (3,5-dihydroxyphenyl) ethanol; DL-2- tert- butylamino-1- (3,5-dihydroxyphenyl) ethanol; rac -2- tert -butylamino-1- (3,5-dihydroxyphenyl) ethanol; Terbutalinum ( Latin ) ;
Molecular formula	C 12 H 19 NO 3
External identifiers / databases
EC number	245-385-8
ECHA InfoCard	100.041.244
PubChem	5403
ChemSpider	5210
DrugBank	DB00871
Wikidata	Q424340
Drug information
ATC code	R03 AC03 ; R03 CC03 ;
Drug class	β 2 sympathomimetics
properties
Molar mass	225.28 g · mol -1
Melting point	119-122 ° C ; 246–248 ° C (2: 1 sulfate);
solubility	Water: 213 g l −1 at 25 ° C
safety instructions
	Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed
GHS labeling of hazardous substances Hemisulfate; danger
H and P phrases	H: 361
	P: 281
Toxicological data	205 mg kg −1 ( LD 50 , mouse , oral , sulfate)
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Terbutaline is a medicinal substance, more precisely a sympathomimetic , which is used for the acute treatment of those forms of dyspnoea that are characterized by a reversible narrowing of the airways , i.e. above all bronchial asthma and chronic obstructive pulmonary disease . Due to its effect on the smooth muscles of the uterus , it is also used to inhibit labor ( tocolysis ).

As a selective β ₂ -sympathomimetic it is a bronchospasmolytic , which is mainly administered " by inhalation ", in emergency therapy also subcutaneously.

Indications

Indications are:

the symptomatic therapy of acute asthma attacks
prophylactic use for exercise-induced bronchial asthma
chronic obstructive bronchitis
as a parenteral application for tocolysis in the case of an impending premature birth
Terbutaline in tablet form for high-flow priapism after SKAT therapy and for spontaneous, more frequent priapisms

Mechanism of action

Corresponding to its properties as a β ₂ mimetic, terbutaline has a stronger effect on the β ₂ adrenoceptors and thus on the smooth muscles of the bronchi , blood vessels and the uterus than on the β ₁ receptors of the heart muscles. This explains the effect of slackening the muscles, leading to expansion of the end bronchi and thus lowering the respiratory resistance and generally making breathing easier or inhibiting labor.

With long-term use, it can be observed that the effect of the drug decreases due to down-regulation of the receptors.

Side effects

Due to the β ₂ - selectivity , the effects on heart activity are mainly in inhalation of the substance low. An increase in the heart rate can also be viewed as a counter-regulation to the expansion of the peripheral blood vessels. However, palpitations may occur, which, along with fine-pitched muscle tremors and tonic convulsions, are typical of sympathomimetic amines. A drop in serum potassium is possible and requires the determination of potassium before the start of treatment.

While inhalative administration of terbutaline leads to fewer systemic side effects than oral or parenteral administration , allergic reactions are more common after inhalation: Quincke's edema , urticaria , rash , drop in blood pressure and collapse states are possible but very rare.

The US Food and Drug Administration (FDA) has recently issued a warning against prolonged use of terbutaline to inhibit labor . If the substance is used to prevent premature birth for more than 72 hours, the cardiac risks considerably outweigh the risks.

chemistry

Stereochemistry

Terbutaline is a chiral drug and contains a stereocenter . Thus, terbutaline consists of two enantiomers , the ( R ) -enantiomer and the ( S ) -enantiomer. The pharmacologically active isomer is the ( R ) -enantiomer. However, the racemate , ie the 1: 1 mixture of both enantiomers, is used therapeutically .

Enantiomers of terbutaline
CAS number: 37394-31-3	CAS number: 90877-48-8

Trade names

Monopreparations

Aerodur (D), Bricanyl (D, A, CH), various generics (D)

Individual evidence

↑ ^a ^b ^c Entry on Terbutaline in the DrugBank of the University of Alberta , accessed October 25, 2014.
↑ Entry on terbutaline. In: Römpp Online . Georg Thieme Verlag, accessed on October 25, 2014.
↑ ^a ^b Data sheet Terbutaline hemisulfate salt from Sigma-Aldrich , accessed on October 23, 2016 ( PDF ).
↑ FDA Drug Safety Communication: New warnings against use of terbutaline to treat preterm labor, January 17, 2011
↑ F. v. Bruchhausen, G. Dannhardt, S. Ebel, AW Frahm, E. Hackenthal, U. Holzgrabe (Eds.): Hagers Handbook of Pharmaceutical Practice: Volume 9: Material PZ , Springer Verlag, Berlin, Edition 5, 2014, p. 804, ISBN 978-3-642-63389-8 .

[DrugBank-1] Entry on Terbutaline in the DrugBank of the University of Alberta , accessed October 25, 2014.

[2] Entry on terbutaline. In: Römpp Online . Georg Thieme Verlag, accessed on October 25, 2014.

[Sigma-3] Data sheet Terbutaline hemisulfate salt from Sigma-Aldrich , accessed on October 23, 2016 ( PDF ).

[4] FDA Drug Safety Communication: New warnings against use of terbutaline to treat preterm labor, January 17, 2011

[Hager-5] F. v. Bruchhausen, G. Dannhardt, S. Ebel, AW Frahm, E. Hackenthal, U. Holzgrabe (Eds.): Hagers Handbook of Pharmaceutical Practice: Volume 9: Material PZ , Springer Verlag, Berlin, Edition 5, 2014, p. 804, ISBN 978-3-642-63389-8 .