From the Guidelines
Hydralazine dosing for infants should start at 0.75 mg/kg per dose, with a maximum dose of 7.5 mg/kg per day, administered four times daily (QID) as needed for hypertension, according to the expert panel on integrated guidelines for cardiovascular health and risk reduction in children and adolescents 1. The initial dose and maximum dose are crucial in managing hypertension in infants while minimizing potential side effects.
- The dose can be adjusted based on the infant's blood pressure response and clinical condition.
- It is essential to monitor for common adverse effects such as tachycardia and fluid retention.
- Hydralazine can cause a lupus-like syndrome in slow acetylators, although this is rare in infants 1.
- The medication works as a direct vasodilator, relaxing vascular smooth muscle primarily in arterioles, which reduces peripheral resistance and lowers blood pressure.
- Continuous monitoring of blood pressure is necessary during administration, as the hypotensive effect typically begins within a specific timeframe.
- Dosing should be carefully managed, taking into account the potential for sodium and water retention, which can impact the infant's fluid status. The expert panel's guidelines provide a foundation for hydralazine dosing in infants, emphasizing the need for careful monitoring and adjustment of the dose to achieve optimal blood pressure management while minimizing adverse effects 1.
From the FDA Drug Label
The usual recommended oral starting dosage is 0.75 mg/kg of body weight daily in four divided doses. Dosage may be increased gradually over the next 3 to 4 weeks to a maximum of 7. 5 mg/kg or 200 mg daily. The recommended starting dose of hydralazine in infants is 0.75 mg/kg of body weight daily, divided into four doses. The maximum dose is 7.5 mg/kg or 200 mg daily 2.
- Key points:
- Starting dose: 0.75 mg/kg/day
- Maximum dose: 7.5 mg/kg or 200 mg daily
- Dose titration: gradual increase over 3 to 4 weeks
From the Research
Hydralazine Doses in Infants
- The available evidence does not provide specific dosage recommendations for hydralazine in infants 3, 4, 5.
- A study on intravenous hydralazine in hospitalized children and adolescents with hypertension found that the median dose was 0.10 mg/kg, with a range of 0.02-0.37 mg/kg 3.
- Another study on the efficacy and safety of intravenous hydralazine for the treatment of hypertension in hospitalized children found that the recommended dose was not specified, but the median reduction in systolic and diastolic blood pressure was 8.5 and 11.5%, respectively 5.
- There is insufficient evidence to determine the safety and efficacy of hydralazine in low birth weight infants with persistent hypoxemic respiratory failure 4.
- The studies available do not provide sufficient information to establish a specific dosage range for hydralazine in infants, and further research is needed to determine the optimal dosage and safety of hydralazine in this population 3, 4, 5.
Safety and Efficacy
- Intravenous hydralazine was found to be well tolerated in hospitalized children, with a variable blood pressure response and 21% of patients achieving a ≥25% reduction in systolic or diastolic blood pressure 5.
- The use of hydralazine in infants with persistent hypoxemic respiratory failure has not been established as effective, and concerns remain regarding adverse effects 4.
- A study comparing the efficacy of nifedipine and hydralazine in hypertensive crisis in pregnancy found that both drugs were safe and effective, but nifedipine had a faster onset of action and required less frequent doses 6.
Limitations
- The available evidence is limited, and further studies are needed to establish the safety and efficacy of hydralazine in infants 3, 4, 5.
- The studies available do not provide sufficient information to establish a specific dosage range for hydralazine in infants, and further research is needed to determine the optimal dosage and safety of hydralazine in this population 3, 4, 5.