Article: Labetalol

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. weight	328.406 g/mol
Pharmacokinetic data
Bioavailability	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 (D in 2nd & 3rd trimesters) 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, and decreases cardiac output.

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

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. By IV, the patient is usually started at 2 mg/minute or 20 mg, with a maximum of 300 mg.

Side effects

Side effects may include:

• Drowsiness
• Fatigue
• Weakness
• Difficulty sleeping
• Diminished sexual function
• Scalp tingling which passes after time.