Lorvas (Chlorthalidone)
Also sold as: Lorvas, Thalitone, Hygroton, Orcal, Chlorthalidone (Cipla)
Pregnancy
Cat B
Lactation
Caution
Schedule
H
Forms
Tablet 12.5mg, 25mg, 50mg
Indications
- Hypertension — preferred thiazide-like diuretic (superior CV outcomes vs hydrochlorothiazide — ALLHAT trial)
- Oedema (heart failure, nephrotic syndrome)
Adult Dosing
Hypertension
12.5–25 mg PO once daily (morning)
Preferred over hydrochlorothiazide for BP control (longer half-life, more consistent effect). Max antihypertensive effect at 25 mg — 50 mg adds little benefit but more metabolic adverse effects.
Oedema
25–50 mg PO once daily or on alternate days
Titrate to clinical response
Pediatric Dosing
Paediatric hypertension: specialist supervised
Renal Dose Adjustment
| CrCl / eGFR | Dose Adjustment |
|---|---|
| CrCl < 30 mL/min | Avoid — ineffective and increased electrolyte disturbance risk |
Hepatic Adjustment
Use cautiously — electrolyte imbalance may precipitate hepatic encephalopathy
Pregnancy & Lactation
Pregnancy: Category B
Generally avoid in pregnancy — diuretics reduce plasma volume; thiazides can cause neonatal thrombocytopenia, electrolyte disturbances, jaundice. Methyldopa, labetalol, nifedipine preferred for hypertension in pregnancy.
Lactation: Caution
Excreted in breast milk — may suppress lactation (reduce milk production). Avoid if possible; use alternative. If must use, monitor infant and maternal milk supply.
Top Drug Interactions
| Interacting Drug | Effect | Severity |
|---|---|---|
| ACE inhibitors / ARBs | Synergistic BP reduction (beneficial combination for hypertension); risk of hypotension with first dose if volume-depleted | Moderate |
| NSAIDs | Reduce diuretic efficacy; increase risk of electrolyte disturbance and acute kidney injury | Moderate |
| Lithium | Thiazides reduce lithium excretion — serious lithium toxicity risk | Major |
| Digoxin | Hypokalaemia from thiazide increases digoxin toxicity risk | Major |
| Antidiabetics | Thiazides cause hyperglycaemia — may worsen diabetes control | Moderate |
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Side Effects
Common
- Hypokalaemia (monitor K+)
- Hyponatraemia
- Hyperuricaemia (can precipitate gout)
- Hyperglycaemia (worsens diabetes)
- Hypercholesterolaemia (mild)
- Dizziness
- Increased urination (especially first weeks)
Serious / Discontinue If
- Severe electrolyte imbalance (hyponatraemia — hyponatraemic encephalopathy)
- Lithium toxicity (if not monitored)
- Hyperuricaemic gout attack
- Impaired glucose tolerance / new-onset diabetes
Contraindications
- Severe renal impairment (CrCl < 30 mL/min)
- Refractory hypokalaemia or hyponatraemia
- Symptomatic hyperuricaemia
- Sulfonamide hypersensitivity (cross-reactivity possible)
Available Indian Brands
| Brand | Manufacturer | Price (approx) |
|---|---|---|
| Lorvas 12.5mg | Franco-Indian | 30 tab ₹48 |
| Lorvas SR 12.5mg | Franco-Indian | 30 tab ₹58 |
| Orcal 12.5mg | Sun Pharma | 30 tab ₹45 |
Monitoring Required
- Blood pressure
- Serum potassium and sodium (at 4 weeks after start, then 6-monthly)
- Serum creatinine and eGFR
- Fasting glucose/HbA1c (diabetics)
- Serum uric acid (if gout history)
- Lithium levels (if on lithium)
Patient Counseling Points
- Take in the morning to avoid night-time urination
- Increased urination in first weeks is normal — do not stop without discussing with doctor
- Eat potassium-rich foods (bananas, oranges, potatoes, spinach) or as prescribed
- Avoid excessive alcohol — worsens diuretic-related dizziness
- Tell your doctor if you develop joint pain — uric acid may rise (gout risk)
- Diabetics: monitor glucose more carefully — chlorthalidone can raise blood sugar
- Avoid NSAIDs (ibuprofen) — they reduce the drug's effectiveness
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Clinically reviewed by: Dr. Meenakshi Iyer, DM (Cardiology), Consultant Cardiologist
Last reviewed: 2026-04-01
References
- ESC Hypertension Guidelines 2023
- ALLHAT Trial (JAMA 2002)
- JNC 8 Guidelines
- BNF — Chlorthalidone