Rinfocan- Prescription Drug Information for Canadians
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Amlodipine
Norvasc
Type of Drug
Calcium channel blocker.
Prescribed for
Angina pectoris; Prinzmetal's angina; and high blood pressure.
General Information
All calcium channel blockers work by blocking the passage of calcium into heart and smooth muscle. Since calcium is an essential factor in muscle contraction, any drug that affects calcium in this way will interfere with the contraction of these muscles. When this happens the amount of oxygen used by the muscles is also reduced. Therefore, Amlodipine can be used in the treatment of angina, a type of heart pain related to poor oxygen supply to the heart muscles. Also, Amlodipine dilates (opens) the vessels that supply blood to the heart muscles and prevents spasm of these arteries. Amlodipine affects the movement of calcium only into muscle cells; it does not have any affect on calcium in the blood.
Cautions and Warnings
Amlodipine may, rarely, cause unwanted low blood pressure
in some people taking it for reasons other than hypertension. This is more of a problem with other calcium channel blockers. Amlodipine may worsen heart failure and should be used with caution if heart failure is present.
Calcium channel blockers, alone and with Aspirin, have caused bruises, black-and-blue marks, and bleeding due to an anticoagulant effect. This is mostly a problem with Nifedipine but should be considered for all calcium channel blockers.
People with severe liver disease break down Amlodipine much more slowly than people with less severe disease or normal livers. Your doctor should take this into account when determining your Amlodipine dosage. Do not take this drug if you have had an allergic reaction to it in the past.
Rapid withdrawal of Amlodipine may cause angina pain. This can be avoided by gradual dosage reduction.
Pregnancy/Breast-feeding
Animal studies with Amlodipine show that it may damage a developing fetus. Other calcium channel blockers can be used to treat severe high blood pressure associated with pregnancy, so there is no reason for pregnant women or those who might become pregnant to take Amlodipine.
It is not known if Amlodipine passes into breast milk. You must consider the potential effect on the nursing infant if breast-feeding while taking this medicine.
Seniors
Older adults, especially those with liver disease, are more sensitive to the effects of this drug because it takes longer to pass out of their bodies; they should be given somewhat . lower doses to start with. Follow your doctor's directions and report any side effects at once.
Possible Side Effects
Common side effects are headache, light-headedness, dizziness, anxiety, nausea, swelling in the arms or legs, heart palpitations, and flushing.
Less common side effects include sleepiness, muscle weakness, cramps or abdominal discomfort, itching, rash,sexual difficulties, wheezing or shortness of breath, muscle cramps, pain, and inflammation.
Rare side effects include nervousness, psychiatric disturbances (anxiety, depression, memory loss, paranoia, psychosis, hallucination, unusual dreams), tingling in the hands or feet, sleeplessness, feelings of ill health, ringing or buzzing in the ears, hand or other muscle tremors, diarrhea, constipation, vomiting, dry mouth, excessive thirst, stomach gas, low blood pressure, slow heartbeat, abnormal heart rhythms, hair loss, bruising, black-and-blue marks, bleeding, stuffed nose sinus inflammation, chest congestion, frequent or painful urination, joint stiffness or pain, weight gain, nosebleeds cough, and appetite loss.
Other side effects reported with Amlodipine are chest pain, blue discoloration of fingers or toes, diffculty swallowing, eye pain, double vision, abnormal vision, conjunctivitis, heart failure, irregular pulse, apathy, agitation, dry skin, skin discoloration, twitching, migraines, cold and clammy skin, loose stools, and taste changes.
Drug Interactions
Amlodipine may interact with beta-blocking drugs to cause heart failure, very low blood pressure, or an increased incidence of angina pain.
Amlodipine may cause unexpected blood-pressure reduction in patients already taking medicine to control their high blood pressure through interaction with other antihypertensive drugs, although this interaction is more likely with other calcium channel blockers.
The combination of Quinidine (for abnormal heart rhythm) and Amlodipine must be used with caution because it can produce low blood pressure, very slow heart rate, abnormal heart rhythms, and swelling in the arms or legs.
Amlodipine can increase the effects of Theophylline products (for asthma and other respiratory problems).
Patients taking Amlodipine who are given Fentanyl as a short-term surgical anesthetic may experience very low bloo pressure.
Food Interactions
Amlodipine can be taken without regard to food or meals.
Usual Dose
5 to 10 milligrams once a day. Do not stop taking Amlodipine abruptly. The dosage should be gradually reduced over a period of time.
Overdosage
Overdose of Amlodipine can cause nausea, weakness, dizziness, confusion, and slurred speech. Overdose victims should be taken to a hospital emergency room, or call your local poison control center for directions. You may be asked to make the victim vomit, probably with Syrup of Ipecac (available at any pharmacy), to remove the medicine from the stomach. If you go to the hospital, ALWAYS bring the medicine bottle.
Special Information
Call your doctor if you develop constipation, nausea, weakness or dizziness, swelling in the hands or feet, difficulty breathing, increased heart pains, or if other side effects are particularly bothersome or persistent.
If you are taking Amlodipine for high blood pressure, be sure to continue taking the drug and follow any instructions for diet restriction or other treatments. High blood pressure is a condition with few recognizable symptoms; it may seem that you are taking medicine for no good reason. Call your doctor or pharmacist if you have any questions.
It isimportant to maintain good dental hygiene while taking Amlodipine and to use extra care when using your toothbrush or dental floss because of the chance that the drug will ,make you more susceptible to some infections.
If you forget a dose of Amlodipine, take it as soon as you remember. If it is almost time for your next regularly scheduled dose, skip the forgotten dose and continue with your regular schedule. Do not take a double dose.
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