11/10, 2007
Calcium Channel Blocking Agents Information
Type of Drug:
Calcium channel blockers (eg, slow channel blockers, calcium ion antagonists); drugs that inhibit the movement of calcium across the cell membrane of cardiac muscle and vascular smooth muscle.
How the Drug Works:
Calcium is involved in blood vessel and heart muscle contraction, nerve impulse transmission and energy storage, and energy use in the heart. Calcium channel blocking agents dilate arteries of the heart and other arteries, may increase or decrease heart rate, may decrease heart conÂtraction, slow ability of the heart to contract, and slow the rate at which nerve impulses are conducted through the heart.
Uses:
To treat angina due to coronary artery spasm (Prinzmetal angina) (amlodipine, nifedipine, nifedipine sustained-release, verapamil).
To treat chronic stable (stress-associated) angina in patients who cannot tolerate or are unresponsive to beta-adrenergic blockers or nitrates (amlodipine, bepridil, diltiazem, nicardipine, nifedipine, nifedipine sustained-release, verapamil only).
To treat unstable angina (verapamil only).
To treat arrhythmias (irregular heartbeats) at rest and during stress in association with digitalis (verapamil only).
To treat high blood pressure (amlodipine, diltiazem sustained-release, felodipine, isradipine, nicardipine, nifedipine sustained-release, nisoldipine, verapamil only).
To improve neurological deficiencies caused by spasms following subarachnoid hemorrhage (SAH) (ruptured vessels in the brain). Therapy must begin within 96 hours and continue for 21 days (nimodipine only).
Unlabeled Uses: Occasionally doctors may prescribe diltiazem to treat unstable angina, Raynaud syndrome, and tardive dyskinesia, and to prevent certain types of heart attack.
Isradipine may be useful in the treatment of chronic stable angina. Nicardipine may be useful in the treatment of congestive heart failure and in combination with aminocaproic acid for SAH.
Occasionally doctors may prescribe nifedipine to lower blood pressure in hypertensive emergencies; to prevent or treat migraine headÂaches; and to treat primary pulmonary (lung) and pregnancy-associated hypertension, asthma, preterm labor, disorders of the esophagus, certain types of heart disorders, coronary artery disease, congestive heart failure, Raynaud syndrome, biliary and renal colic, and cardiomyopathy.
Nimodipine appears to be beneficial in some patients with common and classic migraine and chronic cluster headache.
Occasionally doctors may prescribe verapamil to prevent migraine headache, cluster headache, and exercise-induced asthma; to treat manic-depressive states, night leg cramps, and hypertrophic cardiomyopathy. Verapamil has also been used for paroxysmal supraventricular tachycardia.
Precautions:
New serious arrhythmias: Bepridil has been associated with the occurrence of new serious arrhythmias. Use should be limited to patients in whom other antianginal drugs have failed.
Pregnancy: There are no adaquate and well-controlled studies in pregnant women. Use only if clearly needed and the potential benefits to the mother outweigh the possible hazards to the fetus.
Breastfeeding: Bepridil, diltiazem, nifedipine, and verapamil appear in breast milk. It is not known if amlodipine, felodipine, isradipine, nicardipine, nimodipine, or nisoldipine appear in breast milk. Decide whether to discontinue nursing or the drug, taking into account the importance of the drug to the mother. Consult your doctor.
Children: Safety and effectiveness have not been eastablished in children.
Elderly: Felodipine , nifedipine, and verapamil may result in greater lowering of blooding pressure than younger patients.
Lab Tests: Lab tests may be required periodically during treatment. Tests may include electrocardiograms, serum potassium levels, liver and kidney function tests, blood pressure, and blood and platelet counts.
Drug Interactions:
Tell your doctor or pharmacist if you are taking or planning to take any over the-counter or prescription medications or dietary supplements with calcium channel blocking agents. Doses of one or both drugs may need to be modified or a different drug may need to be prescribed.The following drugs and drug classes interact with calcium channel blocking agents:
- Alcohol (verapamil only)
- Anesthetics antiarrhythmics (eg, flecainide) (verapamil only)
- Antihistamines, nonsedating (eg, loratadine) (bepridil only)
- Antihypertensives (eg, diuretics) (verapamil only)
- Azole antifungals (eg, ketoconazole, itraconazole) (felodipine, nisoldipine only)
- Barbiturates (eg, phenobarbital) (felodipine, nifedipine only)
- Benzodiapines (eg, midazolam) (diltiazem only)
- Beta-blockers (eg, propranolol) calcium salts (verapamil only)
- Carbamazepine (eg, Tegretol) (diltiazem, felodipine, verapamil only)
- Cardiac glycosides (eg, digoxin) (bepridil only)
- Cimetidine (eg, Tagamet)
- Cyclosporine (eg, Neoral) (diltiazem, nicardipine, verapamil only)
- Digoxin (eg, Lanoxin)
- Diltiazem (eg, Cardizem) (nifedipine only)
- Encainide (Enkaid) (diltiazem only)
- Erythromycin (eg, E-Mycin) (felodipine only)
- Fentanyl (eg, Duragesic)
- Grapefruit juice (felodipine, nifedipine, nisoldipine only)
- HMG-CoA reductase inhibitors (eg, lovastatin) (diltiazem, verapamil only)
- Lithium (eg, Eskalith) (verapamil only)
- Euromuscular blockers (eg, atracurium) (verapamil only)
- Nifedipine (eg, Procardia) (diltiazem only)
- Nondepolarizing muscle relaxants (eg, pancuronium) (verapamil only)
- Phenytoin (eg, Dilantin) (felodipine, nisoldipine only)
- Prazosin (eg, Minipress) (verapamil only)
- Primidone (eg, Mysoline) (nifedipine only)
- Procainamide (eg, pronesty) (bepridil only)
- Quinidine (eg, Quinora) (bepridil, nisoldipine, verapamil only)
- Rifampin (eg, Rifadin) (diltiazem, isradipine, nifedipine, verapamil only)
- Tacrolimus (Prograf) (diltiazem only)
- Theophyllines (eg, aminophylline)(diltiazem, verapamil only)
- Tricyclic antidepressants (eg, amitriptyline)(bepridil only)
Side Effects:
Every drug is capable of producing side effects. Many calcium channels blocking agent users experience no, or minor, side effects. The frequency and severity of side effects depend on many factors including dose, duration of therapy, and individual susceptibility. Possible side effects include:
Nervous System: Headache; dizziness; giddiness (felodipine only); lightÂheadedness; fainting; weakness; fatigue; nervousness; anxiety; tremor; general body discomfort; impaired movement; excessive movement (nicardipine only); confusion; irritability; drowsiness; sleep disturbances; difficulty sleeping; abnormal dreams; psychiatric disturbances (eg, depression, amnesia, paranoia, psychosis).
Digestive Tract: Nausea; vomiting; diarrhea; constipation; gas; stomach pain or cramps; indigestion; changes in taste perception; dry mouth; swollen gums (felodipine only); appetite changes (bepridil only).
Respiratory System: Congestion; runny nose; sinus infection; cough; shortÂness of breath; wheezing; sore throat; sneezing; bronchitis; fluid retention in lungs.
Circulatory System: Fluid retention; low blood pressure; high blood pressure; anemia; pounding in the chest; chest pain; decreased heart rate; increased heart rate; abnormal heart rhythm; abnormal electrocardiogram readings; myocardial infarction; AV block; congestive heart failure.
Skin: Rash; skin irritation; flushing; sweating; acne (nimodipine only); itching; hives; abnormal skin sensations (eg, burning, prickling, tingling); hair loss.
Other: Fever; chills; flulike symptoms; muscle cramps or pain; joint stiffÂness or pain; back pain (felodipine only); weight loss; weight gain; noseÂbleed; ringing in ears; pain; blurred vision; difficult urination; painful urination; frequent urination; sexual difficulties; infection (nicardipine only).
Guidelines for Use:
- Dosage is individualized. Take exactly as prescribed.
- Do not change the dose or stop taking this medicine unless advised to do so by your doctor. Abrupt withdrawal may result in increased angina attacks.
- All of the products listed are calcium channel blockers; however, they are not interchangeable. For example, diltiazem cannot be used for nimodipine.
- Extended- or sustained-release - Swallow whole; do not chew, crush, or divide. An empty tablet may appear in stool; this is no cause for concern.
- Amlodipine, felodipine, isradipine, nicardipine - May be taken with or without food. Do not take felodipine with grapefruit juice.
- Verapamil- Verapamil extended-release is usually taken at bedtime with or without food. Take verapamil sustained-release with food in the morning. If heart failure is not severe or rate-related, use digitalis and diuretics before verapamil.
- Oiltiazem sustained-release - The usual dose is taken in the morning on an empty stomach.
- Bepridil- If stomach upset occurs, take with meals or at bedtime. Notify any doctor who treats that you are taking bepridil, as well as any other medications you may be taking. Bepridil use has been associated with the occurrence of new arrhythmias. Use should be limited to patients in whom other anti anginal drugs have failed.
- Nimodipine - Take preferably less than 1 hour before or 2 hours after meals. Therapy to improve neurological deficiencies caused by spasms following SAH must begin within 96 hours and continue for 21 days. If capsule cannot be swallowed (eg, time of surgery, unconsciousness), a hole can be made in both ends of the capsule with an 18 gauge needle, and the contents extracted into a syringe for oral administration.
- Nisoldipine - Do not take with grapefruit juice or with high-fat meals.
- Adalat CC - Take once daily on an empty stomach.
- Felodipine - May cause swollen or bleeding gums. Good dental hygiene decreases incidence and severity of this condition.
- Calcium channel blockers may interfere with normal blood-clotting mechanisms. Contact your doctor if unusual bleeding or bruising of the skin occurs.
- Low blood pressure may occur, but is usually well tolerated. It is more likely to occur in patients who are also taking beta-blockers (eg, propranolol).
- Beta-blockers should be tapered slowly rather than stopped abruptly before starting nicardipine or nifedipine therapy. When starting nicardipine therapy, taper beta-blockers over 8 to 10 days with coadministration.
- Maintain use of potassium supplementation or potassium-sparing diuretics.
- If a dose is missed, take it as soon as possible. If several hours have passed or it is nearing time for the next dose, do not double the dose to catch up, unless advised to do so by your doctor. If more than one dose is missed or it is necessary to establish a new dosage schedule, contact your doctor or pharmacist.
- Notify your doctor if you experience irregular heartbeat, increased frequency or severity of angina, shortness of breath, swelling of hands and feet, dizziness, constipation, nausea, or low blood pressure (eg, lightÂheadedness).
- Notify your doctor if you experience symptoms of an allergic reaction (eg, itching, rash, hives, difficulty breathing).
- Inform your doctor if you are pregnant, become pregnant, plan on becoming pregnant, or are breastfeeding.
- Lab tests may be required to monitor therapy. Be sure to keep appointments.
- Store at controlled room temperature (59 to 77 F) in a tightly sealed container. Keep away from light and moisture. Protect nimodipine from freezing.
Tagged under:blood vessel, calcium, Cardiovasculars, drugs, heart muscle contraction, muscle side effects