Maximum Daily Dose of Hydralazine for Hypertension
The maximum daily dose of hydralazine for treating hypertension in adults is 300 mg in divided doses. 1, 2
Dosing Guidelines and Administration
Initial Dosing
- Start with 10 mg four times daily for the first 2-4 days 2
- Increase to 25 mg four times daily for the remainder of the first week 2
- For the second week and beyond, increase to 50 mg four times daily as needed 2
Titration and Maximum Dosing
- Titrate to the lowest effective dose for maintenance therapy 2
- Maximum daily dose is 300 mg in divided doses for resistant hypertension 1, 2
- For most patients, a maximum of 150 mg daily is recommended to avoid drug-induced systemic lupus erythematosus 1
Administration Considerations
- Typically administered in 3-4 divided doses daily 1
- When combined with beta-blockers, three times daily administration may be sufficient 1
- Administration with food results in higher plasma levels 2
Special Populations
Pediatric Dosing
- Initial pediatric dose: 0.75 mg/kg of body weight daily in four divided doses 2
- Maximum pediatric dose: 7.5 mg/kg/day up to 200 mg/day 1, 2
Acetylator Status Considerations
- Slow acetylators achieve therapeutic effect at lower doses (D50 of 0.87 mg/kg) 3
- Fast acetylators may require higher doses (D50 of 1.68 mg/kg) 3
- However, specific dosing adjustments based on acetylator status are not provided in guidelines 1
Combination Therapy
- For resistant hypertension, lower doses of hydralazine combined with a thiazide diuretic and/or beta-blocker should be considered before reaching maximum doses 1, 2
- When used with other antihypertensives, individual titration is essential to ensure the lowest possible therapeutic dose of each drug 2
- Hydralazine should be used with appropriate background diuretic and beta-blocker therapy to counteract increased sympathetic tone and sodium retention 1
Safety Considerations and Monitoring
- Important safety warning: Doses above 150 mg daily significantly increase the risk of drug-induced systemic lupus erythematosus 1
- Regular monitoring is required with prolonged therapy, including complete blood counts and antinuclear antibody titers 1
- Monitor for excessive hypotension, especially when combined with other potent antihypertensives like diazoxide 2
Clinical Pearls
- While the maximum dose is 300 mg daily, most patients should be maintained on the lowest effective dose 2
- The 300 mg maximum dose should be reserved for resistant cases where lower doses combined with other antihypertensives have failed 1, 2
- Twice-daily dosing with slow-release formulations may provide adequate 24-hour control in both rapid and slow acetylators 4
- Combination with beta-blockers helps mitigate reflex tachycardia and may improve overall efficacy 5