Hydralazine And Hydrochlorothiazide

Drug Overview

The fixed-dose combination of Hydralazine and Hydrochlorothiazide is a dual-action antihypertensive medication primarily used to control hypertension (primary hypertension) and related cardiovascular diseases. This medication combines vasodilators and diuretics, lowering vascular resistance through vasodilation while promoting water and salt excretion to achieve stable blood pressure.

This medication is typically used for patients whose blood pressure cannot be effectively controlled with a single component or in severe hypertension cases requiring rapid volume reduction. Its combination allows for lower doses of each component, reducing the risk of side effects, but must be used strictly according to a physician's instructions.

Brand Names and Generic Name

The generic name of this combination drug is Hydralazine and Hydrochlorothiazide. Common brand names include "Apo-Hydralazine HCTZ" and "Hytiazide." Different regions may have different trade names. Patients should refer to the medication label and confirm whether the active ingredients include these two components.

Drug Classification

This medication is a combination of vasodilators and diuretics, specifically classified as:

Hydralazine: Peripheral arterial vasodilator (vasodilator class)
Hydrochlorothiazide: Thiazide diuretic

This combination employs a dual mechanism of lowering blood pressure by directly reducing vascular resistance and decreasing fluid volume.

Indications

Main indications include:

Primary hypertension (first-line or add-on therapy)
Hypertensive patients with edema
Patients unresponsive to other antihypertensive medications

In some cases, it may also be used for blood pressure abnormalities associated with heart failure.

Common Side Effects

Mild side effects: Dizziness, fatigue, muscle soreness, nocturia, mild hypotension (dizziness upon standing).

Serious side effects: If any of the following symptoms occur, discontinue medication immediately and seek medical attention:

Skin rash or urticaria
Shortness of breath or chest pain
Limb weakness or speech difficulties
Severe edema or oliguria

Warnings and Precautions

Contraindications include:

Allergy to any component
Severe renal impairment
Hyperkalemia or metabolic acidosis

This drug is classified as Category C by the FDA for pregnancy; use during pregnancy should involve a risk-benefit assessment, and it should be avoided during breastfeeding.

Drug Interactions

Special caution is needed when combined with:

Other antihypertensives (such as beta-blockers, ACE inhibitors) which may have additive effects
Insulin or oral hypoglycemic agents which may affect blood glucose control
Non-steroidal anti-inflammatory drugs (NSAIDs) which may reduce diuretic efficacy

Consult a physician before taking herbal medicines or supplements (such as potassium tablets).

Dosage and Administration

The usual initial dose is 1-2 times daily, with specific doses adjusted based on patient age and liver/kidney function. It should be taken with meals to reduce gastrointestinal discomfort, but the tablets should not be chewed or opened. The physician may gradually adjust the dose based on blood pressure monitoring results.

Do not increase or decrease the dose on your own. If blood pressure control is inadequate, return to the doctor promptly. Do not self-increase the dose to avoid hypotensive crises.

Missed Dose Management

If a dose is missed and more than 4 hours remain before the next dose, take it as soon as possible. If it is close to the next scheduled dose, skip the missed dose and resume the regular schedule. Do not double the dose.

Overdose Management

Overdose may cause severe hypotension, syncope, electrolyte disturbances. Seek immediate medical attention, which may involve intravenous fluids or vasopressor therapy. Keep the medication out of reach of children to prevent accidental ingestion.

Frequently Asked Questions

What tests should patients regularly undergo while taking this medication?

Patients should regularly monitor blood pressure, serum potassium, renal function, and hemoglobin levels. Hydrochlorothiazide may cause hypokalemia or changes in renal function, while Hydralazine may affect the hematologic system. Blood and urine tests are recommended every 3-6 months, with frequency adjusted according to the physician's instructions.

Should medication be taken with food? How should missed doses be handled?

It is recommended to take the medication with meals to reduce gastrointestinal discomfort, but at a consistent time each day. If a dose is missed, take it as soon as remembered, but if close to the next dose, skip the missed dose. Do not double the dose to compensate. Long-term missed doses causing blood pressure fluctuations should be discussed with the doctor to adjust the medication plan.

How should side effects like dizziness or muscle pain be managed?

Dizziness may result from rapid blood pressure decline. Move slowly when standing and ensure a safe environment. If dizziness persists or worsens, measure blood pressure and adjust posture accordingly. Muscle pain accompanied by fever or weakness may be due to metabolic changes from Hydrochlorothiazide and should be reported to the physician immediately for assessment.

What interactions should be considered when combined with other antihypertensives or supplements?

Combining with beta-blockers or calcium channel blockers may cause excessive blood pressure lowering, requiring dose adjustments. Avoid concurrent use of potassium supplements or potassium-sparing diuretics to prevent hyperkalemia. Use of NSAIDs may reduce antihypertensive effects; inform the physician of all medications being taken.

How should diet be adjusted during treatment to reduce side effects?

Adopt a low-sodium diet to enhance blood pressure reduction, and consume potassium-rich foods (such as bananas and spinach) to counteract diuretic-induced potassium loss. Avoid excessive alcohol intake to prevent worsening dizziness or palpitations. If dehydration or abnormal urination occurs, adjust fluid intake and inform the physician.

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