Felodipine
Felodipine(中文:非洛地平) is a dihydropyridine calcium-channel blocker. It is used in the management of hypertension and angina.
Pronunciation
Felodipine extended-release 2.5mg
| Generic Name: | Felodipine |
|---|---|
| Brand Name: | PLENDIL |
| 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 |
|---|---|---|---|
| Felodipine Extended-Release Tablet 2.5mg | FELO03 | P1S1S3 | ADALAT RETARD TABLET |
| Felodipine Extended-Release Tablet 5mg | FELO01 | P1S1S3 | ADALAT RETARD TABLET |
Mechanism of Action
Felodipine 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, nifedipine 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
Felodipine is given orally in an extended release formulation once daily.
Dosage
Agina
- BY MOUTH
- Adult: 5 mg daily, increased if necessary to 10 mg daily.
Hypertension
- BY MOUTH
- Adult: i5 mg daily, usual maintenance 5 – 10 mg once daily.
Elderly:initially 2.5 mg daily, to be taken in the morning; usual maintenance 5 – 10 mg once daily.
Side Effects
The following definitions of frequencies are used:
Very common ≥ 1/10
Common ≥ 1/100 to < 1/10
Uncommon ≥ 1/1,000 to < 1/100
Rare ≥ 1/10,000 to < 1/1,000
Very rare < 1/10,000
| System Organ Class | Frequency | Adverse reactions |
|---|---|---|
| Nervous system disorder | Common | Headache |
| Cardiac disorders | UnCommon | Tachycardia, palpitations |
| Vascular disorders | Common | Flushing |
| Gastro-intestinal disorders | UnCommon | Abdominal pain, nausea, constipation |
| Very rare | Gum hyperplasia | |
| General disorders | Common | Peripheral oedema |
Pharmacokinetics
Absorption
Felodipine is administered as extended-release tablets, from which it is completely absorbed in the gastrointestinal tract. The extended-release tablets produce a prolonged absorption phase of felodipine. This results in even felodipine plasma concentrations within the therapeutic range for 24 hours. Maximum blood plasma levels (tmax) are achieved with the prolonged-release form after 3 to 5 hours. The rate but not the extent of absorption of felodipine is increased when taken simultaneously with food with a high fat content.
Distribution
Felodipine is about 99% bound to plasma protein (albumin).
Metabolism
Felodipine is extensively metabolized in the liver by cytochrome P450 3A4 (CYP3A4) and all identified metabolites are inactive. Felodipine is a high clearance medicinal product with an average blood clearance of 1200 ml/min. There is no significant accumulation during long-term treatment.
Elimination
The half-life of felodipine in the elimination phase is approximately 25 hours and steady state is reached after 5 days.
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 |
