1. Clinical Overview
A fixed-dose combination (FDC) antihypertensive agent containing an angiotensin II receptor blocker (ARB), Olmesartan Medoxomil, and a beta-1 selective adrenergic blocker, Metoprolol Succinate (extended-release). This combination provides complementary mechanisms for blood pressure control by blocking the renin-angiotensin-aldosterone system (RAAS) and reducing sympathetic nervous system activity. It is indicated for the management of essential hypertension where single-agent therapy is insufficient. The combination offers improved efficacy, potential for better compliance, and a favorable side effect profile compared to higher doses of monotherapy.
| Onset | Duration | Bioavailability |
|---|---|---|
| Olmesartan: 1-2 hours; Metoprolol Succinate (ER): Gradual over several hours. | Olmesartan: >24 hours; Metoprolol Succinate (ER): Approx. 24 hours (due to extended-release formulation). | Olmesartan Medoxomil: ~26%; Metoprolol Succinate: ~30-40%. |
2. Mechanism of Action
The combination exerts a dual antihypertensive effect. Olmesartan selectively blocks the binding of angiotensin II to the AT1 receptor, preventing vasoconstriction, aldosterone secretion, and sympathetic activation. Metoprolol succinate is a cardioselective beta-1 adrenergic receptor antagonist that reduces heart rate, myocardial contractility, and renin release from the kidneys. Together, they inhibit both the RAAS and sympathetic nervous system, leading to reduced peripheral vascular resistance and cardiac output.
3. Indications & Uses
- Essential Hypertension (Stage 1 & 2) where monotherapy is inadequate
4. Dosage & Administration
Adult Dosage: One tablet (Olmesartan 20mg + Metoprolol Succinate 50mg) once daily. May be increased after 2-4 weeks to a maximum of Olmesartan 40mg + Metoprolol Succinate 100mg once daily, if needed. Usually taken in the morning.
Administration: Swallow the tablet whole with a glass of water, with or without food. Do not crush, chew, or split the tablet as it will compromise the extended-release mechanism of metoprolol. Take at the same time each day. If a dose is missed, take it as soon as remembered unless it is almost time for the next dose. Do not double the dose.
5. Side Effects
Common side effects may include:
- Dizziness
- Fatigue/asthenia
- Headache
- Bradycardia
- Cold extremities
- Gastrointestinal disturbances (diarrhea, nausea, abdominal pain)
- Upper respiratory tract infection symptoms
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Other antihypertensives (Diuretics, CCBs, ACEIs) | Additive hypotensive effect, risk of severe hypotension. | Major |
| Digoxin | Metoprolol may increase digoxin concentration; increased risk of bradycardia. | Moderate |
| Antiarrhythmics (Amiodarone, Disopyramide) | Increased risk of bradycardia and myocardial depression. | Major |
| NSAIDs (e.g., Ibuprofen, Diclofenac) | May reduce antihypertensive effect of olmesartan; increased risk of renal impairment. | Moderate |
| Potassium supplements / Potassium-sparing diuretics (Spironolactone) | Increased risk of hyperkalemia with olmesartan. | Major |
| Lithium | Olmesartan may increase lithium levels and risk of toxicity. | Major |
| CYP2D6 Inhibitors (Fluoxetine, Paroxetine, Quinidine) | Increase metoprolol plasma levels, enhancing its effects and side effects. | Moderate |
| Clonidine | Risk of severe rebound hypertension if clonidine is withdrawn while on beta-blocker. | Major |
| Insulin / Oral hypoglycemics | Metoprolol may mask tachycardia as a sign of hypoglycemia; may potentiate hypoglycemia. | Moderate |
| Verapamil / Diltiazem | Concurrent use with metoprolol increases risk of bradycardia, AV block, and heart failure. | Major |
7. Patient Counselling
- DO take the tablet at the same time every day, with or without food.
- DO swallow the tablet whole with water. Do NOT crush, chew, or break it.
- DO continue taking this medicine even if you feel well. Hypertension often has no symptoms.
- DO inform all your doctors and dentists that you are taking this medicine before any surgery or new prescription.
- DO monitor your blood pressure and pulse rate regularly as advised by your doctor.
- DONT stop taking this medicine suddenly, especially the beta-blocker component, without consulting your doctor.
- DONT take over-the-counter NSAIDs (like ibuprofen) for pain/fever without consulting your doctor.
- DONT use potassium supplements or salt substitutes containing potassium without medical advice.
8. Toxicology & Storage
Overdose: Primarily extensions of pharmacologic effects: Severe hypotension, bradycardia, heart block, cardiogenic shock, cardiac arrest, bronchospasm, impaired consciousness, coma, nausea, vomiting. Hypoglycemia may occur in diabetics.
Storage: Store below 30°C in a cool, dry place, protected from light and moisture. Keep out of reach of children. Do not use after the expiry date printed on the pack.