Generic Name: Nifedipine
Brand Name: Adalat, Adalat CC, Nifedical XL, Procardia, Procardia XL
Classification: Antianginal, Antihypertensive, Calcium Channel Blocker
- Angina pectoris
- Vasospastic angina
- Raynaud’s phenomenon
Mechanism of Action
The action of Nifedipine is based on the fact that this medication works by slowing the movement of calcium in the muscle cells that are found in the blood vessel wall. This drug blocks the calcium chennels in these muscle cells. As a result, the muscle cells relax because the calcium is needed by the muscle cells to contract. Thus depriving the muscle cells with calcium would end in muscular relaxation. Nifedipine specifically acts on the muscle cells of the arterial walls, relaxing the arteries. The relaxation effect allows the arteries in the body to widen. This is a double effect of this drug.
When the small arteries of the body is relaxed and widened the resistance that the heart pushes to pump the blood around the body also decreases. This in return lowers the pressure within the blood vessels. Thus, Nifedipine is used in decreased an elevated blood pressure.
Aside from lowering the blood pressure, the widening effect on the small arteries and arteries of the heart also improves blood circulation and therefore increases the oxygen supply to the heart. This unique feature of Nifedipine makes it ideal in the management of episodes of angina. Because chest pain in angina is caused by the insufficient blood supply in the heart. Thus, as this drug improves oxygen supply and reduces the effort of the heart to make the blood pump, it can be used for preventing angina attacks.
A circulatory disorder called a Raynaud’s phenomenon can also be managed by Nifedipine. With Raynaud’s phenomenon, the blood vessels in the hands go into spasm and contarct excessively when the hands are cold. As a result, the hands go white, numb and painful. With the administration of Nifedipine, the peripheral arteries in the hands are relaxed that would cause them to widen and improve blood circulation in the fingers.
- Sick sinus syndrome
- 2nd– or 3rd– degree AV block (unless an artificial pacemaker is in place)
- Blood pressure <90 mmHg
- Coadministration with grapefruit juice
Use Cautiously in patients with:
- Severe hepatic impairment
- History of porphyria
- Geriatric patients
- Severe renal impairment
- History of serious ventricular arrhythmias or CHF
- Blurred vision
- Peripheral edema
- Chest pain
- Dry mouth
- Nausea and vomiting
- Muscle cramps
- Monitor BP and pulse before therapy, during dose titration and periodically during the therapy.
- ECG should be monitored during prolonged therapy.
- Monitor intake and output rations and daily weight.
- Assess for signs of CHF such as peripheral edema, rales/crackles, dyspnea, weight gain and jugular vein distention.
- For patients with angina, assess the location, duration, intensity and precipitating factors of patient’s angina pain.
- Instruct patient on technique for monitoring pulse. If heart rate is below 50 beats per minute, the physician should be notified.
- PO medications may be administered without regard to meals. If in case GI irritation becomes a problem, it can be administered with meals.
- Adalat should never be administered with grapefruit juice. As it can increase the level of the medicine in the blood and thus increase its effect on the blood pressure. This could make the patient feel dizzy. If the patient has been regularly drinking grapefruit juice, this effect can last for at least three days after his or her last drink.
- Sublingual use is not recommended due to serious adverse drug reactions.
- Instruct the patient to avoid concurrent use of alcohol or OTC medications and natural or herbal products especially cold preparations, without consulting the doctor.
- Advise patient to take medication exactly as directed. Missed doses should be taken as soon as remembered unless almost time for next dose.
- Instruct the patient not to double doses.
- Drug should be discontinued gradually.
- Caution patient to change positions slowly to minimize orthostatic hypotension.
- Advise patient to avoid driving or other activities requiring alertness until response to the medication is known.
- Caution patient to wear protective clothing and use sunscreen to prevent photosensitivity reactions.
- Instruct patient on importance of maintaining good dental hygiene and seeing dentists frequently for teeth cleaning to prevent tenderness, bleeding and gingival hyperplasia (gum bleeding).
- Instruct the patient to contact the physician immediately if the following are experienced or observed:
- Irregular heartbeat
- Swelling of hands and feet
- Pronounced dizziness
- Severe or persistent headache