1. Clinical Overview
A fixed-dose combination (FDC) antihypertensive medication containing an angiotensin II receptor blocker (ARB), Telmisartan, and a dihydropyridine calcium channel blocker (CCB), Amlodipine. This combination provides synergistic blood pressure control by blocking the renin-angiotensin-aldosterone system (RAAS) and inhibiting calcium influx into vascular smooth muscle, leading to vasodilation. It is a first-line therapy for essential hypertension, especially in patients requiring more than one agent, and is widely used in the Indian population due to its efficacy, tolerability, and once-daily dosing.
| Onset | Duration | Bioavailability |
|---|---|---|
| Amlodipine: 6-12 hours; Telmisartan: 3 hours. Full therapeutic effect for the combination is typically seen within 1-2 weeks of continuous dosing. | Amlodipine: >24 hours; Telmisartan: >24 hours. The combination provides sustained 24-hour blood pressure control with once-daily dosing. | Telmisartan: 42-58%; Amlodipine: 64-90%. Food slightly reduces the bioavailability of Telmisartan. |
2. Mechanism of Action
The combination exerts a dual mechanism: 1) Telmisartan selectively and competitively blocks the binding of angiotensin II to the AT1 receptor, inhibiting its vasoconstrictor and aldosterone-secreting effects. 2) Amlodipine inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle, causing peripheral arterial vasodilation and reduced peripheral vascular resistance. The synergistic action leads to enhanced blood pressure reduction and potential organ protection.
3. Indications & Uses
- Essential Hypertension (Stage 1 and 2) in patients where monotherapy is inadequate
4. Dosage & Administration
Adult Dosage: One tablet (Telmisartan 80mg + Amlodipine 5mg) orally once daily. Dose may be titrated after 2-4 weeks based on response. Maximum: Telmisartan 80mg + Amlodipine 10mg daily.
Administration: Can be taken with or without food, but consistency is advised. Preferably taken at the same time each day, in the morning. Swallow whole with a glass of water. Do not crush or chew.
5. Side Effects
Common side effects may include:
- Peripheral edema (less than Amlodipine monotherapy)
- Headache
- Dizziness
- Flushing
- Fatigue
- Nausea
- Palpitations
- Ankle swelling
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Other Antihypertensives (Diuretics, Beta-blockers, ACE inhibitors) | Additive hypotensive effect; risk of severe hypotension. | Major |
| Potassium-sparing diuretics (Spironolactone, Eplerenone), Potassium supplements | Increased risk of hyperkalemia. | Major |
| NSAIDs (e.g., Ibuprofen, Diclofenac) | May reduce antihypertensive effect and increase risk of renal impairment, especially in elderly or volume-depleted. | Major |
| Lithium | Increased serum lithium levels and toxicity (Telmisartan may reduce renal clearance). | Major |
| Strong CYP3A4 Inhibitors (e.g., Ketoconazole, Itraconazole, Ritonavir, Clarithromycin) | Increase Amlodipine plasma concentration, risk of hypotension and edema. | Moderate |
| Simvastatin | Amlodipine may increase simvastatin exposure, increasing risk of myopathy/rhabdomyolysis. Limit simvastatin dose to 20mg daily. | Moderate |
| Digoxin | Amlodipine may increase digoxin levels; monitor for toxicity. | Moderate |
| Aliskiren | Concomitant use with ARBs in diabetic patients or those with renal impairment increases risk of renal impairment, hypotension, and hyperkalemia. | Major |
7. Patient Counselling
- DO take the medicine at the same time every day, preferably in the morning.
- 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 medication before any surgery or new prescription.
- DO get your blood pressure checked regularly as advised by your doctor.
- DONT stop taking this medicine suddenly without consulting your doctor, as your blood pressure may rise quickly.
- DONT take over-the-counter NSAIDs (like Ibuprofen) for pain or fever without consulting your doctor.
- DONT use potassium supplements or salt substitutes containing potassium without medical advice.
- DONT double the dose if you miss one. Take it as soon as you remember, but skip if it's almost time for the next dose.
8. Toxicology & Storage
Overdose: Profound hypotension, reflex tachycardia, bradycardia (vagal stimulation), circulatory shock, and electrolyte disturbances. Marked peripheral vasodilation leading to shock. Lethargy and confusion may occur.
Storage: Store below 30°C, in a cool, dry place. Protect from light and moisture. Keep out of reach of children. Do not use after the expiry date printed on the pack.