Introduction
Nifedipine is a medicine used to treat high blood pressure (hypertension) and to prevent angina (heart-related chest pain). It belongs to a class of medicines known as calcium channel blockers. It lowers blood pressure and reduces the workload of the heart. This helps prevent heart attacks and strokes.
Nifedipine may be prescribed alone or along with other medicines. The dose and how often you need it will be decided by your doctor so that you get the right amount to treat your condition. Your doctor may adjust the dose depending on how you respond to this medicine and your blood pressure levels. You can take it at any time of the day, with or without food, but it is best to take it at the same time each day. Take this medicine as soon as you have taken it out of the packet. It is sensitive to light and may not work properly if it is left out of the pack for too long.
Keep taking it for as long as advised by your doctor. Even if you feel well, do not stop this medicine on your own because high blood pressure often has no symptoms. If you stop taking it, your condition may get worse.
Keeping active with regular exercise, reducing your weight and eating a healthy diet will also help control your blood pressure. Follow your doctor's advice while taking this medicine.
The most common side effects include fatigue, swelling in the feet or ankles, dizziness, unusual heartbeat (palpitations), flushing, constipation, and headache. Consult your doctor if any of these bother you, or do not go away.
Before taking it, let your doctor know if you have any heart, liver or kidney problems. Pregnant or breastfeeding women should also consult their doctor for advice before taking this medicine. You also need to tell your doctor what other medicines you are taking, especially those used to treat high blood pressure or heart conditions. Avoid excessive alcohol intake while taking this medicine as it can significantly decrease your blood pressure and make you feel dizzy or light-headed. You should have your blood pressure checked regularly to make sure that this medicine is working properly.
Uses of Nifedipine
- Hypertension (high blood pressure)
- Angina (heart-related chest pain)
Side effects of Nifedipine
Common
- Ankle swelling
- Dizziness
- Edema (swelling)
- Fatigue
- Flushing (sense of warmth in the face, ears, neck and trunk)
- Headache
- Palpitations
How to use Nifedipine
Take this medicine in the dose and duration as advised by your doctor. Swallow it as a whole. Do not chew, crush or break it. Nifedipine may be taken with or without food, but it is better to take it at a fixed time.
How Nifedipine works
Nifedipine is a calcium channel blocker. In high blood pressure, it normalizes the blood pressure by relaxing the blood vessels to reduce the pressure on them, thereby improving the blood flow in the body. The enhanced blood flow in the body further relaxes the heart muscles by reducing the workload on the heart. It also improves the oxygen flow in the body, thereby, preventing any heart-related chest pain.
What if you forget to take Nifedipine?
If you miss a dose of Nifedipine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular schedule. Do not double the dose.
Indication
Hypertension, Angina pectoris, Raynaud's syndrome, Stroke prevention
Administration
Immediate-release: May be taken with or without food. Avoid grapefruit juice.
Retard, GITS & OROS: May be taken with or without food. Avoid grapefruit juice. Swallow whole, do not chew/crush.
Adult Dose
Oral
Hypertension
Adult: Immediate-release: Initially, 5 mg tid. Maintenance: 10-20 mg tid.
Extended-release: Initially, 10-40 mg bid, or 20-90 mg once daily.
Angina pectoris
Adult: Immediate-release: Initially, 10 mg tid. Maintenance: 10-20 mg tid.
Extended-release: 10-40 mg bid or 30-60 mg once daily.
Raynaud's syndrome
Adult: Immediate-release: 5-20 mg tid.
Elderly: Dose reduction may be necessary.
Hepatic impairment: Dose reduction may be necessary.
Contraindication
Acute MI, cardiogenic shock, acute unstable angina, treatment of anginal attack in chronic stable angina.
Mode of Action
Nifedipine prevents Ca ion from entering the slow channels of cardiac and smooth muscles during depolarisation, producing peripheral and coronary vasodilatation. It reduces afterload, peripheral resistance and BP; increases coronary blood flow and causes reflex tachycardia. It has little or no effect on cardiac conduction and rarely has negative inotropic activity.
Precaution
Patients w/ hypotension, poor cardiac reserve, heart failure, severe aortic stenosis, DM, underlying severe GI narrowing (extended-release tab). Avoid abrupt withdrawal as it may casue rebound angina. Hepatic impairment. Elderly. Pregnancy and lactation. Patient Counselling Discontinue if ischaemic pain follows after admin. Monitoring Parameters Monitor BP, heart rate.
Lactation: Drug is distributed into breast milk; manufacturer suggests discontinuing drug or refraining from nursing (however, American Academy of Pediatrics states that drug is safe for nursing)
Side Effect
>10%
Peripheral edema (10-30%),Dizziness (23-27%),Flushing (23-27%),Headache (10-23%),Heartburn (11%),Nausea (11%)
1-10%
Muscle cramps (8%),Mood change (7%),Nervousness (7%),Cough (6%),Dyspnea (6%),Palpitations (6%),Wheezing (6%),Hypotension, transient (5%),Urticaria (2%),Pruritus (2%),Constipation (<2%),Chest pain (<2%)
Frequency Not Defined
Gingival hyperplasia,Agranulocytosis,Erectile dysfunction
Interaction
Enhanced antihypertensive effects w/ other antihypertensives, aldesleukin, and antipsychotics. Concomitant use w/ fentanyl during surgery caused severe hypotension. May modify insulin and glucose responses. Attenuation of tachycardic effect when used w/ benazerpril. Prothrombin time may be increased w/ coumarin anticoagulants. Increased serum levels w/ CYP3A4 inhibitors (e.g. azole antifungals, cimetidine, erythromycin, HIV-protease inhibitors, nefazodone, fluoxetine, quinupristin/dalfopristin).
Potentially Fatal: Decreased bioavailability and efficacy w/ strong CYP3A4 inducers (e.g. rifampicin, phenytoin, carbamazepine).