From the FDA Drug Label
DOSAGE AND ADMINISTRATION DOSAGE MUST BE INDIVIDUALIZED. The recommended initial dosage is 100 mg twice daily whether used alone or added to a diuretic regimen. After 2 or 3 days, using standing blood pressure as an indicator, dosage may be titrated in increments of 100 mg b.i. d. every 2 or 3 days. The usual maintenance dosage of labetalol HCl is between 200 and 400 mg twice daily. ... Patients with severe hypertension may require from 1,200 to 2,400 mg per day, with or without thiazide diuretics The maximum dose of Labetalol for hypertension is 2,400 mg per day 1.
- The dose can be administered in divided doses, either twice daily or three times daily.
- Titration increments should not exceed 200 mg twice daily.
From the Research
The maximum dose of labetalol for hypertension is 2400 mg per day, as supported by the study published in 1979 2, which reported that some patients received doses of up to 2400 mg daily.
Key Points to Consider
- For oral administration, treatment usually begins with 100 mg twice daily, which can be gradually increased every 2-3 days as needed to control blood pressure.
- For intravenous (IV) use in hypertensive emergencies, labetalol can be given as repeated boluses of 20-80 mg every 10 minutes up to a maximum of 300 mg, or as a continuous infusion at 0.5-2 mg/min, as noted in the example answer.
- However, a more recent study from 2019 3 assessed the safety of high-dose intravenous labetalol in adults and found that doses greater than 300 mg in 24 hours were not associated with adverse safety outcomes, although they did observe a high rate of bradycardia and hypotension.
- Labetalol works as both an alpha-1 and beta-adrenergic receptor blocker, providing vasodilation while preventing reflex tachycardia, making it particularly useful for hypertensive emergencies.
- Common side effects include dizziness, fatigue, and nausea, and labetalol should be used cautiously in patients with asthma, COPD, heart failure, or diabetes, with dosage adjustments necessary in patients with hepatic impairment since the drug is primarily metabolized by the liver.
Important Considerations
- The study from 1983 4 compared labetalol to metoprolol in the treatment of mild to moderate hypertension and found that labetalol was effective, but it did not provide information on the maximum dose.
- The review of long-term treatment with labetalol from 1982 5 reported a mean daily dose of 700 mg, with a range of 100-2400 mg, and noted that no tolerance to the anti-hypertensive effect was seen.
- The open study from 1978 6 assessed the effectiveness and tolerance of labetalol in difficult hypertensive patients and found that good blood pressure control was readily achieved, with the majority of patients controlled on doses ranging from 300 to 600 mg per day.