labetalol, Normodyne, Trandate (cont.)
Omudhome Ogbru, PharmD
Omudhome Ogbru, PharmD
Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.
Medical and Pharmacy Editor:
Postural hypotension (a rapid decrease in blood pressure when going from the lying or seated position to the standing position that may cause light-headedness or fainting) occurs rarely. Patients should be observed for this possible side effect within two to four hours of the first labetalol dose and after any changes in dose.
Other important side effects include:
GENERIC AVAILABLE: Yes
PREPARATION: Tablets: of 100, 200 and 300 mg; Injection: 5 mg/ml
STORAGE: Tablets should be stored between 20 C - 30 C (36 F - 86 F).
DOSING: The recommended starting oral dose of labetalol is 100 mg twice daily and the dose can be increased by 100 mg twice daily every 2-3 days based on the response of the blood pressure. Usual maintenance doses are 200-400 mg twice daily. Patients with severely high blood pressure may require 1.2 to 2.4 g daily.
Side effects may be less if labetalol is given in three daily doses rather than two. Stopping or changing the dose of the drug should be directed by a physician because serious side effects may occur. The initial intravenous dose of labetalol is 20 mg injected over 2 minutes. Additional injections of 40 or 80 mg may be administered every 10 minutes as needed up to a total dose of 300 mg. Labetalol also may be administered by intravenous infusion at 1-2 mg/minute.
DRUG INTERACTIONS: Labetalol can mask early warning symptoms of hypoglycemia (low blood sugar) such as tremors and increased heart rate which are the result of activation of the adrenergic nervous system. Therefore, people with diabetes taking medications that lower blood sugar such as insulin or oral antidiabetic medications may need to increase the frequency with which they monitor their blood sugar in order to prevent hypoglycemia.
Combining labetalol with tricyclic antidepressants such as amitriptyline (Elavil, Endep), imipramine (Tofranil), or nortriptyline (Pamelor) may lead to an increase in tremor which is a side effect of tricyclic antidepressants.
Medically Reviewed by a Doctor on 12/30/2014
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