From the Guidelines
Hydralazine 75mg is an appropriate dose for the treatment of heart failure, as evidenced by the ESC guidelines, which recommend a target dose of 75mg, in combination with ISDN 40mg t.i.d., if tolerated 1. When considering the use of hydralazine, it's essential to evaluate the patient's overall clinical context, including the presence of heart failure, hypertension, or other comorbidities.
- The typical starting dose of hydralazine is 10-25mg four times daily, with gradual increases as needed, and 75mg likely represents a single dose within a multiple daily dose regimen.
- The usual maintenance dose ranges from 50-100mg per dose, taken 3-4 times daily, and it's crucial to space doses evenly throughout the day for consistent blood pressure control.
- Common side effects of hydralazine include headache, rapid heartbeat, and fluid retention, and the medication works by directly relaxing the smooth muscles in blood vessel walls, causing vasodilation and reducing blood pressure.
- According to the American Heart Association, hydralazine can be added as a fifth-line agent in the treatment of resistant hypertension, particularly in patients with heart failure, and should be used in combination with nitrates and background diuretic and beta-blocker therapy 1.
- The total daily dose of hydralazine should be less than 150mg to avoid drug-induced systemic lupus erythematosus, and patients should be monitored regularly for potential side effects and changes in blood pressure.
From the FDA Drug Label
Although the precise mechanism of action of hydrALAZINE is not fully understood, the major effects are on the cardiovascular system. HydrALAZINE apparently lowers blood pressure by exerting a peripheral vasodilating effect through a direct relaxation of vascular smooth muscle HydrALAZINE is rapidly absorbed after oral administration, and peak plasma levels are reached at 1 to 2 hours. Plasma levels of apparent hydrALAZINE decline with a half-life of 3 to 7 hours.
The dose of 75mg hydralazine is not explicitly mentioned in the provided drug labels. Key points about hydralazine include:
- It is a peripheral vasodilator that lowers blood pressure
- It is rapidly absorbed after oral administration
- Peak plasma levels are reached at 1 to 2 hours
- Plasma levels decline with a half-life of 3 to 7 hours However, the labels do not provide information on the specific dose of 75mg. 2 2
From the Research
Hydralazine Dosage
- The provided studies do not specifically mention a dosage of 75mg hydralazine.
- However, study 3 mentions that hydralazine was administered in doses of 25,50, and 100 mg b.i.d. (twice daily) to patients with persisting hypertension who received combined diuretic and beta-blocker therapy.
Comparison with Nifedipine
- Study 4 assesses the effects of additional long-term administration of nifedipine in patients with hypertension uncontrolled by existing therapy, which includes hydralazine or prazosin in some cases.
- Studies 5 and 3 compare the effects of nifedipine versus hydralazine on sympathetic activity, cardiac function, and blood pressure in patients with hypertension persisting on diuretic plus beta-blocker therapy.
- These studies suggest that both nifedipine and hydralazine can lower blood pressure, but nifedipine may be more effective in certain cases 5, 3.
Efficacy and Safety
- Study 6 compares the effectiveness, safety, and tolerability of once-daily nifedipine and amlodipine treatment in patients with mild-to-moderate essential hypertension, but does not mention hydralazine.
- Studies 4, 5, and 3 provide some information on the efficacy and safety of hydralazine, but more research would be needed to fully understand its effects at a dosage of 75mg.