Dose and Dosage:
- The typical starting dose of hydralazine for hypertension is 10 mg orally four times daily.
- Dosage adjustments may be made based on individual response and tolerance, with increments of 25 to 50 mg every 4 to 6 hours, up to a maximum of 300 mg per day.
Frequency:
- Hydralazine is usually administered orally, with a frequency of four times daily.
Route of Administration (ROA):
- Hydralazine is primarily administered orally in tablet form.
- In acute settings or severe hypertension, it can also be given intravenously, typically in a hospital setting.
Mechanism of Action (MOA):
- Hydralazine is a direct-acting vasodilator that relaxes smooth muscles in arterioles, leading to peripheral vasodilation and decreased systemic vascular resistance.
Pharmacokinetics (PK):
- The medication is rapidly absorbed after oral administration, with peak plasma concentrations reached within 1 to 2 hours.
- Hydralazine undergoes extensive hepatic metabolism, with a half-life of approximately 2 to 3 hours.
Pharmacodynamics (PD):
- By dilating arterioles, hydralazine reduces systemic vascular resistance, leading to decreased blood pressure.
- It may also increase cardiac output by reducing afterload.
Pathophysiology:
- Hydralazine’s vasodilatory effects help alleviate hypertension by reducing peripheral resistance to blood flow, thus lowering blood pressure.
Indications:
- Hydralazine is indicated for the treatment of essential hypertension, especially when other antihypertensive agents are ineffective or contraindicated.
Contraindications:
- Contraindications to hydralazine use include hypersensitivity to the medication, coronary artery disease, mitral valvular rheumatic heart disease, and aortic stenosis.
Drug Interactions:
- Hydralazine may potentiate the hypotensive effects of other antihypertensive agents, leading to additive blood pressure-lowering effects.
- Concurrent use with phosphodiesterase-5 inhibitors like sildenafil may result in severe hypotension.
Precautions:
- Patients should be closely monitored for signs of hypotension, especially during initial dose titration.
- Regular monitoring of blood pressure, heart rate, and signs of fluid retention is essential during hydralazine therapy.
- Caution is warranted in patients with a history of lupus erythematosus due to the risk of drug-induced lupus-like syndrome.
Medication Information and Guidelines
| Purpose: Hydralazine is primarily used to treat high blood pressure (hypertension) by dilating blood vessels and reducing resistance to blood flow. Usage Instructions: Administration: Hydralazine is typically taken orally in the form of tablets. Dosage: The initial dosage is often 10 mg taken four times daily, with adjustments made based on individual response and tolerance, up to a maximum of 300 mg per day. Other Uses: In addition to hypertension, hydralazine may be prescribed for heart failure when standard treatments are insufficient. Specific Precautions: Hypotension: Be cautious of low blood pressure, especially when initiating treatment or adjusting dosage. Lupus: Individuals with a history of lupus erythematosus should be monitored for lupus-like symptoms, as hydralazine can trigger drug-induced lupus. Dietary Considerations: No specific dietary restrictions are typically associated with hydralazine use. Missed Dose: If you forget to take a dose, take it as soon as you remember. However, if it’s almost time for your next dose, skip the missed one and continue with your regular schedule. Possible Side Effects: Common Side Effects: Headache, dizziness, flushing, nausea, vomiting, and palpitations. Serious Side Effects: Severe hypotension, drug-induced lupus-like syndrome, blood disorders, and angina. Storage and Disposal: Store hydralazine tablets at room temperature, away from moisture and heat. Keep the medication in its original container, tightly closed, and out of reach of children. Dispose of any unused or expired medication properly, following local regulations or guidelines. Emergency Situations: In case of an overdose or severe adverse reactions, seek immediate medical attention or contact a poison control center. Emergency treatment may involve supportive measures to stabilize blood pressure and manage symptoms. |