Usage
- Indapamide is primarily prescribed for the treatment of hypertension (high blood pressure) and edema (fluid retention) associated with congestive heart failure. It helps lower blood pressure and reduce excess fluid in the body.
- Pharmacological Classification: Indapamide is classified as a thiazide-like diuretic and antihypertensive agent.
- Mechanism of Action: Indapamide acts by inhibiting sodium reabsorption in the distal convoluted tubule of the nephron, promoting increased excretion of sodium, chloride, and water, thus reducing blood volume and lowering blood pressure. It also has vasodilatory effects, contributing to its antihypertensive action.
Alternate Names
- There are no widely used alternate names for Indapamide.
- Brand Names: Lozol, Natrilix, Indapamid, Tertensif, Fludex.
How It Works
- Pharmacodynamics: Indapamide decreases peripheral vascular resistance and lowers blood pressure. Its diuretic effect reduces blood volume.
- Pharmacokinetics:
- Absorption: Indapamide is well-absorbed orally.
- Metabolism: It is extensively metabolized in the liver.
- Elimination: Primarily eliminated via the kidneys (70%) and in feces (23%) as metabolites.
- Mode of Action: Indapamide inhibits sodium reabsorption in the distal convoluted tubule, leading to increased sodium and water excretion. Its vasodilatory action is thought to involve the modulation of calcium channels and prostaglandin synthesis. It may bind to sulfonylurea receptors in vascular smooth muscle.
- Elimination Pathways: Renal and hepatic excretion, involving CYP3A4 enzyme metabolism to a small extent.
Dosage
Standard Dosage
Adults:
- Hypertension: Initial dose: 1.25 mg orally once daily, preferably in the morning. The dose can be increased to 2.5 mg/day after 4 weeks if needed. Maximum dose: 2.5 mg/day or 5 mg/day depending on the guidelines being followed.
- Edema (Heart Failure): Initial dose: 2.5 mg orally once daily. May be increased to 5 mg/day if needed.
Children:
- Indapamide is not recommended for use in children due to lack of safety and efficacy data.
Special Cases:
- Elderly Patients: Start with a lower dose (1.25 mg/day) and monitor closely for side effects, adjusting the dose based on renal function.
- Patients with Renal Impairment: Contraindicated in severe renal failure (creatinine clearance <30 mL/min). Caution is advised in moderate renal impairment. Dose adjustment may be required.
- Patients with Hepatic Dysfunction: Contraindicated in severe hepatic impairment. Caution is advised in moderate hepatic impairment.
- Patients with Comorbid Conditions: Careful monitoring and dose adjustments may be needed in patients with diabetes, gout, or electrolyte imbalances.
Clinical Use Cases
Indapamide is not typically used in acute clinical settings such as intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations like cardiac arrest. It is intended for chronic management of hypertension and edema.
Dosage Adjustments
Dose adjustments should be based on patient response, renal function, and potential drug interactions. Genetic polymorphism information regarding Indapamide’s metabolism is not routinely used for dose adjustments.
Side Effects
Common Side Effects:
- Headache, dizziness, fatigue, muscle cramps, increased urination (especially during initial treatment), nausea, vomiting, constipation, dry mouth, rash, itching.
Rare but Serious Side Effects:
- Hyponatremia (low sodium), hypokalemia (low potassium), hypotension (low blood pressure), dehydration, arrhythmias, pancreatitis, angioedema, severe skin reactions (Stevens-Johnson syndrome).
Long-Term Effects:
- Electrolyte imbalances, gout exacerbation, photosensitivity.
Adverse Drug Reactions (ADR):
- Angioedema, severe skin reactions (e.g. Stevens-Johnson syndrome), life-threatening irregular heartbeat.
Contraindications
- Hypersensitivity to indapamide or other sulfonamides.
- Anuria (no urine output).
- Severe renal or hepatic impairment.
- Hypokalaemia.
Drug Interactions
- Lithium, NSAIDs, ACE inhibitors, ARBs, other antihypertensives, corticosteroids, digoxin, potassium-sparing diuretics, certain antiarrhythmics (e.g., amiodarone, sotalol), and many others. Refer to a comprehensive drug interaction resource for a complete list.
- CYP3A4 interaction is minimal.
- Alcohol can potentiate the hypotensive effects.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: Use is generally avoided during pregnancy. Potential benefits should outweigh the risks, and it is not typically the preferred choice for treating pregnancy-induced hypertension.
- Fetal risks and teratogenicity are not well-established, but there is a possibility of fetal or neonatal jaundice, thrombocytopenia, and electrolyte disturbances.
- Limited information is available on breast milk excretion, but safer alternatives are preferred.
Drug Profile Summary
- Mechanism of Action: Thiazide-like diuretic with vasodilatory properties. Inhibits sodium reabsorption, reduces blood volume and peripheral vascular resistance.
- Side Effects: Headache, dizziness, fatigue, electrolyte imbalances, rash. Serious: angioedema, severe skin reactions.
- Contraindications: Hypersensitivity to sulfonamides, anuria, severe renal/hepatic impairment.
- Drug Interactions: Numerous, including lithium, NSAIDs, other antihypertensives.
- Pregnancy & Breastfeeding: Generally avoided.
- Dosage: 1.25-2.5 mg/day for hypertension; 2.5-5 mg/day for edema. Adjust for renal/hepatic impairment and elderly.
- Monitoring Parameters: Blood pressure, electrolytes (especially potassium and sodium), renal and hepatic function, uric acid.
Popular Combinations
- Perindopril (an ACE inhibitor) and Indapamide: often used together to control blood pressure, especially in patients with diabetes.
Precautions
- General Precautions: Assess renal and hepatic function, electrolyte levels, and history of sulfa allergy before starting.
- Specific Populations: Avoid in pregnancy and breastfeeding if possible. Adjust dose in elderly and patients with renal/hepatic impairment.
- Lifestyle Considerations: Moderate alcohol intake, avoid excessive sun exposure.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Indapamide?
A: 1.25 mg once daily for hypertension, may increase to 2.5 mg/day; 2.5 mg once daily for edema, may increase to 5 mg/day.
Q2: What are the common side effects of Indapamide?
A: Headache, dizziness, fatigue, increased urination, muscle cramps.
Q3: Is Indapamide safe during pregnancy?
A: Generally avoided during pregnancy. Use only if potential benefit outweighs the risk.
Q4: What are the serious side effects of Indapamide?
A: Angioedema, severe skin reactions, electrolyte imbalances (hypokalemia, hyponatremia), life-threatening irregular heartbeats.
Q5: Can Indapamide be used with other antihypertensive medications?
A: Yes, it can be combined with other antihypertensives like ACE inhibitors, ARBs, or beta-blockers. Dosage adjustments may be necessary.
Q6: How does Indapamide differ from thiazide diuretics?
A: It has a longer duration of action and potentially fewer metabolic side effects compared to some thiazides. It’s chemically distinct, not possessing a thiazide ring.
Q7: What should I monitor in patients taking Indapamide?
A: Blood pressure, electrolytes (potassium, sodium), renal function, hepatic function, and uric acid levels.
Q8: Does Indapamide interact with grapefruit juice?
A: There are no known significant interactions with grapefruit juice.
Q9: Can Indapamide be crushed or chewed?
A: Standard tablets can be crushed if necessary. Slow-release tablets should not be crushed or chewed, as it alters their release profile.
Q10: What is the mechanism of Indapamide’s vasodilatory action?
A: Thought to involve modulation of calcium channels and prostaglandin synthesis. It might also interact with sulfonylurea receptors in vascular smooth muscle.
Please note: This information is current as of February 16, 2025, and is intended for use by qualified medical professionals. Always consult the latest prescribing information and guidelines before making any clinical decisions.
