The Full Wiki

Labetalol: Wikis

Advertisements
  

Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.

Encyclopedia

From Wikipedia, the free encyclopedia

Labetalol
Systematic (IUPAC) name
(RS)-2-hydroxy-5-{1-hydroxy-2-[(1-methyl-3-phenylpropyl)amino]ethyl}benzamide
Identifiers
CAS number 36894-69-6
ATC code C07AG01
PubChem 3869
DrugBank APRD01062
ChemSpider 3734
Chemical data
Formula C19H24N2O3 
Mol. mass 328.406 g/mol
SMILES eMolecules & PubChem
Pharmacokinetic data
Bioavailability 90-100%
Protein binding 50%
Metabolism hepatic pass metabolism,
Half life Tablet: 6-8 hours; IV: 5.5 hours
Excretion Excreted in urine, not removed by hemodialysis
Therapeutic considerations
Pregnancy cat. C
One of few drugs used for PIH
Legal status Prescription only
Routes oral iv
 Yes check.svgY(what is this?)  (verify)

Labetalol (Normodyne, Trandate, fixed combination with hydrochlorothiazide: Normozyde) is a mixed alpha/beta Adrenergic antagonist, which is used to treat high blood pressure.[1]

Contents

Chemistry

Labetalol has stereoisomers.[2] It is a racemic mixture of four isomers. Two of these isomers, the (S,S)- and (R,S)- forms are inactive. The third, the (S,R)-isomer, is a powerful α1 blocker. The fourth isomer, the (R,R)-isomer, is a mixed nonselective β blocker and selective β2 agonist.

It works by blocking these adrenergic receptors, which decreases peripheral vascular resistance without significantly altering heart rate or cardiac output. The β:α antagonism of Labetalol is approximately 3:1.[3][4]

Indications

It has a particular indication in the treatment of pregnancy-induced hypertension which is commonly associated with pre-eclampsia. [5]

It is also used to treat chronic hypertension of pheochromocytoma and hypertensive crisis.[3]

Administration

Labetalol is available in 100, 200, and 300 mg tablets and intravenously (only as Trandate) in 5 mg/ml solution. Adults taking tablets usually start with 100 mg twice daily, with a maximum of 2.4 g/day. In cases of emergency dosage might be higher. IV doses are usually started at 20mg over 2 minutes. Additional doses of 40mg, then 80mg may be administered every ten minutes as needed. Additional 80mg doses can be given to a total maximum dose of 300 mg. Additionally, labetalol can be administered by IV infusion at a rate of 2mg/minute, with a maximum dose of 300mg.

Side effects

Side effects may include:

Contraindications

Labetalol has relative contraindications for use in patients with asthma, congestive heart failure, any degree of heart block, bradycardia, or those in cardiogenic shock.

References

  1. ^ Fahed S, Grum DF, Papadimos TJ (2008). "Labetalol infusion for refractory hypertension causing severe hypotension and bradycardia: an issue of patient safety". Patient Saf Surg 2: 13. doi:10.1186/1754-9493-2-13. PMID 18505576. PMC 2429901. http://www.pssjournal.com/content/2//13. 
  2. ^ Riva E, Mennini T, Latini R (December 1991). "The alpha- and beta-adrenoceptor blocking activities of labetalol and its RR-SR (50:50) stereoisomers". Br. J. Pharmacol. 104 (4): 823–8. PMID 1687367. 
  3. ^ a b Katzung, Bertram G. (2006). Basic and clinical pharmacology. New York: McGraw-Hill Medical. p. 170. ISBN 0-07-145153-6. 
  4. ^ D A Richards, J Tuckman, and B N Prichard (October 1976). "Assessment of alpha- and beta-adrenoceptor blocking actions of labetalol.". Br J Clin Pharmacol 3 (5): 849–855. PMID PMC1428931. 
  5. ^ http://www.bnf.org/bnf/bnf/56/2488.htm?q=%22labetalol%22
  6. ^ Shiohara T, Kano Y (2007). "Lichen planus and lichenoid dermatoses". in Bolognia JL. Dermatology. St. Louis: Mosby. p. 161. ISBN 1-4160-2999-0. 
Advertisements

Advertisements






Got something to say? Make a comment.
Your name
Your email address
Message