Duofast (Amlodipine + Olmesartan): A Combined Antihypertensive

Duofast is a combined antihypertensive preparation containing Amlodipine, a calcium channel blocker, and Olmesartan Medoxomil, an angiotensin II receptor blocker (ARB). It is indicated for the treatment of hypertension (high blood pressure) and can be used as an initial therapy for patients likely to need multiple agents to reach their blood pressure goals.

How Duofast Works (Pharmacology)

Duofast works through two complementary mechanisms:

• Amlodipine: As a dihydropyridine calcium channel blocker, it inhibits the influx of calcium ions into vascular smooth muscle. This causes peripheral arterial vasodilation, which directly reduces peripheral vascular resistance and lowers blood pressure.
• Olmesartan Medoxomil: This is an ARB that selectively blocks the binding of angiotensin II to the AT1 receptor. Angiotensin II is a powerful vasoconstrictor. By blocking its effects, Olmesartan prevents blood vessels from narrowing and decreases aldosterone secretion, thus lowering blood pressure.

Key Indications & Benefits

Duofast is indicated for:

• Treatment of hypertension alone or in combination with other agents.
• Initial therapy in patients who are likely to require multiple medications to achieve blood pressure goals.

Dosage & Administration

The dosage should be individualized and can be adjusted as needed.

• Initial Therapy: The recommended starting dose is 5/20 mg once daily for 1 to 2 weeks, and can be titrated up to a maximum of 10/40 mg once daily.
• Elderly (>75 years): The initial dose of Amlodipine should be 2.5 mg. Since the lowest dose of Duofast is 5/20 mg, initial therapy with this combination is not recommended for patients over 75 years old.

Important Considerations & Warnings

It is crucial to discuss your full medical history with your doctor before taking Duofast.

Contraindications:

• Co-administration with Aliskiren in patients with diabetes.

Side Effects:

• Most common: Peripheral edema (swelling), headache, flushing, and dizziness.
• Less common: Sprue-like enteropathy (intestinal problems).

Pregnancy & Lactation:

• Pregnancy Category D: It is contraindicated in the 2nd and 3rd trimesters due to the risk of fetal death. It should be discontinued as soon as pregnancy is detected.
• Lactation: It is not known if the components are excreted in human milk. A decision must be made to either discontinue nursing or discontinue the drug.

Precautions & Warnings:

• Hypotension: Use with caution in patients who are volume- or salt-depleted.
• Cardiac Conditions: Use with caution in patients with severe aortic stenosis or severe obstructive coronary artery disease, as it may increase the frequency, duration, or severity of angina.

Drug Interactions:

• NSAIDs (including COX-2 inhibitors): May reduce the antihypertensive effect of Olmesartan. Blood pressure, renal function, and electrolytes should be monitored.

Overdose Effects

• There is no information available regarding overdose effects in humans.

Storage Conditions

Store below 30°C, away from light and out of the reach of children.