Labetalol

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Labetalol
Systematic (IUPAC) name
2-hydroxy-5-[1-hydroxy-2- (4-phenylbutan-2-ylamino)-ethyl]-benzamide
Identifiers
CAS number	36894-69-6
ATC code	C07AG01
PubChem	3869
DrugBank	APRD01062
Chemical data
Formula	C₁₉H₂₄N₂O₃
Mol. mass	328.406 g/mol
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

Labetalol (Normodyne, Trandate, fixed combination with hydrochlorothiazide: Normozyde) is an alpha-1 and beta adrenergic blocker used to treat high blood pressure. It works by blocking these adrenergic receptors, which slows sinus heart rate, decreases peripheral vascular resistance.

It has a particular indication in the treatment of pregnancy-induced hypertension.

1 Administration
2 Side effects
3 Contraindications
4 References

[edit] 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 two times a day, with a maximum of 2.4 g/day. In an emergency situation, this may 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.

[edit] Side effects

Side effects may include:

Drowsiness
Fatigue
Weakness
Difficulty sleeping
Diminished sexual function
Scalp tingling which passes after time.
A rare but potentially lethal side effect is respiratory distress.

[edit] Contraindications

Labetalol should not be used in patients that have asthma, congestive heart failure, any degree of heart blocks, slow heart rates or those in cardiogenic shock

[edit] References

Hodgson, Barbara B., and Kizior, Robert J. Saunders Nursing Drug Handbook 2006. St. Louis, MO: Elsevier, Saunders, 2006. bledsoe "prehospital emergency pharmacology" upper Saddle River, New Jersey: Pearson 2005

v • d • e Beta blockers (C07)

Non-selective β antagonists	Metipranolol • Nadolol • Oxprenolol • Penbutolol • Pindolol • Propranolol • Tertatolol • Timolol • Sotalol

β₁ antagonists (cardioselective)	Atenolol • Acebutolol • Celiprolol • Betaxolol • Bisoprolol • Esmolol • Metoprolol • Nebivolol

Mixed α₁/β antagonists	Carvedilol • Labetalol