Monotrate (Isosorbide Mononitrate)
Also sold as: Monotrate, Imdur, Monosorb, Ismo, Nitrocontin
Pregnancy
Cat C
Lactation
Caution
Schedule
H
Forms
Tablet IR 10mg, 20mg +1
Indications
- Prophylaxis of angina pectoris (chronic stable angina)
- Post-MI angina management
- Variant angina (Prinzmetal's)
- Angina in COPD patients (where beta-blockers are contraindicated)
Adult Dosing
Angina prophylaxis (IR)
10-20 mg PO BD
IMPORTANT: Asymmetric dosing — take morning and midday (NOT evening) to allow 8-12 hour nitrate-free interval and prevent tolerance. E.g., 8 AM and 2 PM.
Angina prophylaxis (SR/XL)
30-120 mg PO once daily in the morning
SR formulation; single morning dose provides nitrate-free period overnight
Pediatric Dosing
Not routinely used in children
Renal Dose Adjustment
| CrCl / eGFR | Dose Adjustment |
|---|---|
| Any CrCl | No adjustment needed |
Hepatic Adjustment
Use with caution in severe hepatic impairment; reduce dose and monitor
Pregnancy & Lactation
Pregnancy: Category C
Limited data; use only if clearly needed. Causes reflex tachycardia.
Lactation: Caution
Unknown excretion in breast milk; avoid unless essential.
Top Drug Interactions
| Interacting Drug | Effect | Severity |
|---|---|---|
| PDE-5 inhibitors (sildenafil, tadalafil, vardenafil) | ABSOLUTE CONTRAINDICATION — severe, potentially fatal hypotension | Major |
| Antihypertensives / Calcium channel blockers | Additive hypotension | Moderate |
| Alcohol | Additive hypotension, severe dizziness | Moderate |
| Riociguat | Additive hypotension — contraindicated | Major |
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Side Effects
Common
- Headache (very common — nitrate-induced vasodilation)
- Dizziness
- Flushing
- Orthostatic hypotension
- Reflex tachycardia
Serious / Discontinue If
- Severe hypotension (especially with PDE-5 inhibitors)
- Syncope
- Methemoglobinemia (overdose, rare)
Contraindications
- Hypersensitivity to nitrates
- Concurrent PDE-5 inhibitors (sildenafil, tadalafil) — fatal hypotension
- Hypertrophic obstructive cardiomyopathy (HOCM)
- Severe aortic stenosis
- Cardiogenic shock
- Severe anemia
Available Indian Brands
| Brand | Manufacturer | Price (approx) |
|---|---|---|
| Monotrate 20 | Sun Pharma | 10 tab ₹42 |
| Monosorb 20 | Torrent | 10 tab ₹35 |
| Imdur 30 SR | AstraZeneca | 10 tab ₹85 |
| Ismo 20 | Roche (imported) | 10 tab ₹55 |
Monitoring Required
- Blood pressure (orthostatic measurement)
- Headache frequency (may indicate tolerance)
- Heart rate (reflex tachycardia)
Patient Counseling Points
- NEVER take with sildenafil (Viagra), tadalafil (Cialis) or similar drugs — can be fatal
- For IR tablets: take first dose in morning, second dose at noon — NOT in evening (to prevent tolerance)
- Headache is common initially — usually settles after 1-2 weeks
- Rise slowly — can cause dizziness especially on standing
- Avoid alcohol
- DO NOT stop suddenly if on long-term therapy without doctor advice
Stop Googling drug references mid-consultation
EasyClinic auto-flags Monotrate interactions, renal cutoffs, and pregnancy warnings the moment you write the prescription. Built-in safety net for every Indian doctor.
Clinically reviewed by: Dr. Priya Sharma, DM (Cardiology), Senior Cardiologist
Last reviewed: 2026-04-01
References
- BNF — Isosorbide Mononitrate
- ESC Stable CAD Guidelines 2019
- ACC/AHA Chest Pain Guidelines 2021