Amlodipine

Cardiovascular Drug

Drug class: Calcium-channel Blocker, CCB

Amlodipine (NORVASC)（中文：氨氯地平）is a dihydropyridine calcium-channel blocker. It is used in the management of hypertension and angina.

Pronunciation

Amlodipine 10mg

Amlodipine 5mg

HA Code:
Generic Name:	Amlodipine
Brand Name:	NORVASC
Class:	Cardiovascular Drug
Subclass:	Calcium-channel Blocker, CCB
Legal Classification:	P1S1S3

Drug Names

Generic Name 藥物化學名稱	HA Code 藥物代碼	Legal Classification法律藥物分類	Brand Name 品牌名稱
Amlodipine Besylate Tablet 5mg	AMLO01	P1S1S3	NORVASC
Amlodipine Besylate Tablet 10mg	AMLO02	P1S1S3	NORVASC

Mechanism of Action

Amlodipine relaxes and widens blood vessels. It does this by blocking calcium going into muscles in the heart and blood vessels. Muscles need calcium to contract, so when you block the calcium, it makes the muscle cells relax. This lowers your blood pressure and makes it easier for your heart to pump blood around your body. In angina, amlodipine works by improving the blood and oxygen supply to your heart. Angina is chest pain that comes on when not enough blood gets to the muscles of the heart. This usually happens because the arteries going to the heart become hardened and narrowed.

Route of Administration

Amlodipine is given orally as the besylate, but doses are expressed in terms of the base. Amlodipine besylate 6.9 mg is equivalent to about 5 mg of amlodipine.

Dosage

Agina

• BY MOUTH
• Adult: initially 5 mg once daily; maximum 10 mg per day

Hypertension

• BY MOUTH
• Adult: initially 5 mg once daily; maximum 10 mg per day

Elderly

Amlodipine used at similar doses in elderly or younger patients.

Hepatic impairment

May need dose reduction – half-life prolonged

Side Effects

System Organ Class	Frequency	Adverse reactions
Nervous system disorder	Common	Dizziness, headache (especially at the beginning of the treatment)
Eye disorders	Common	Visual disturbance (including diplopia)
Cardiac disorders	Common	palpitations
	Uncommon	Arrhythmia (including bradycardia, ventricular tachycardia and atrial fibrillation)
Vascular disorders	Common	flushing
Respiratory disorders	Common	dyspnoea
Gastro-intestinal disorders	Common	Abdominal pain, nausea, dyspepsia, altered bowel habits (including diarrhoea and constipation)
	Very rare	Gingival hyperplasia
Musculoskeletal and connective tissue disorders	Common	Ankle swelling, muscle cramps
General disorders	Common	Oedema, fatigue, asthemia

Pharmacokinetics

After an oral dose, peak blood concentrations occur after 6 to 12 hours.

The bioavailability varies but is usually about 60 to 65%.

Amlodipine is reported to be about 98% bound to plasma proteins. It has a prolonged terminal elimination half-life of 35 to 50 hours and steady-state plasma concentrations are not achieved until after 7 to 8 days of use.

Amlodipine is extensively metabolized in the liver; metabolites are mostly excreted in urine, with less than 10% of a dose as unchanged drug.

How long does amlodipine take to work?

Amlodipine starts to work on the day you start taking it, but it may be a couple of weeks before it takes full effect.

Simvastatin:	Co-administration of multiple doses of 10 mg of amlodipine with 80 mg simvastatin resulted in a 77% increase in exposure to simvastatin compared to simvastatin alone. Limit the dose of simvastatin in patients on amlodipine to 20 mg daily.
Contraindication:	cardiogenic shock, significant aortic stenosis, unstable angina

FAQ

How should I take the tablet?

You will usually take amlodipine once a day. You can take it at any time of day, but try to make sure it is around the same time every day. You can take amlodipine with or without food.

What should I avoid while taking?

Avoid eating grapefruit or drinking grapefruit juice while taking amlodipine. Grapefruit juice can increase amlodipine in your body and make side effects worse, such as feeling dizzy, flushing or getting headaches.