Nifedipine
Nifedipine(中文:硝苯地平) is a dihydropyridine calcium-channel blocker. It is used in the management of hypertension and angina.
Pronunciation
Nifedipine 20mg (ADALAT RETARD 20mg)
Nifedipine 5mg (ADALAT RETARD 5mg)
| Generic Name: | Nifedipine |
|---|---|
| Brand Name: | ADALAT RETARD |
| 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 |
|---|---|---|---|
| Nifedipine SR Tablet 20mg | NIFE03 | P1S1S3 | ADALAT RETARD TABLET |
Mechanism of Action:
Nifedipine 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:
Nifedipine is given orally in a sustained-release formulation.
Dosage
Agina
- BY MOUTH
- Adult: 10 mg twice daily, adjusted according to response to 40 mg twice daily.
Hypertension
- BY MOUTH
- Adult: 10 mg twice daily, adjusted according to response to 40 mg twice 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
After oral administration nifedipine is rapidly and almost completely absorbed. The systemic availability of orally administered nifedipine is 45 – 56% owing to a first pass effect. Maximum plasma and serum concentrations are reached at 1.5 to 4.2 hours with nifedipine. Simultaneous food intake leads to delayed, but not reduced absorption.
Distribution
Nifedipine is about 95% bound to plasma protein (albumin).
Metabolism
After oral administration, nifedipine is metabolized in the gut wall and in the liver.
Nifedipine is excreted in the form of its metabolites predominantly via the kidney and about 5 – 15% via the bile in the faeces.
Elimination
The terminal elimination half-life is 6 – 11 hours because of delayed absorption. No accumulation of the substance after the usual dose was reported during long-term treatment.
How long does nifedipine take to work?
Nifedipine (Adalat Retard) tablets have extended-release properties, so they absorb in the body slowly over time and can take up to 4 hours to reach its “peak” effect.
Drug Management
Drug Interaction:
Nifedipine (Adalat Retard) tablets have extended-release properties, so they absorb in the body slowly over time and can take up to 4 hours to reach its “peak” effect.
