Pfizer Inc.'s Norvasc, in combination with another drug, helped lower patients' risk of heart attack, stroke and death.
Norvasc is a derivative of dihydropyridine belongs to the group of drugs called Calcium Channel Blockers and causes anti-anginal and hypotensive effects. After binding with dihydropyridine receptors, it blocks calcium channels thus lowering the transmembranal transportation of Ca2+ in to the cell. Anti-anginal effect is caused by dilating of coronary and peripheral arteries and arterioles: in cases of stenocardia(acute heart pain) lowers the expression of myocardial ischemia. Dilatation of the peripheral arterioles lowers the total peripheral resistance, decreases the overall heart afterload and the level of oxygen required for the heart muscle. By dilatation of the main coronary arteries the quantity of oxygen transported to the ischemic zones of the heart is increased and development of coronary artery constriction is prevented. Hypotensive action is caused by direct vasodilatation influence on the vessels plain muscles. The hypotensive effect is prolonged and dose dependent.
- Artherial Hypertension( different origin)
- Stenocardia (acute heart pain)
- Silent (asymptomatic) myocardial ischemia
- Cardiac decompensation (as subsidiary therapy)
To treat the above mentioned conditions Norvasc can be used alone or with additional therapy.
Contradictions and precautions:
- There are certain conditions that restrict the use of Norvasc. These are:
- Hypersensitivity to Norvasc or any other dihydropyridines
- Severe arterial hypotension
- Lactation period
Norvasc should be used with caution if the following apply to you:
- Arterial hypotension
- Arterial stenosis
- Chronic cardiac insufficiency
- Renal insufficiency
- Severe myocardial infraction(within a month period after the conditions occurrence)
- In people younger than 18 years(efficacy and safety not established)
- Old age.
If any of the above mentioned apply to you then a dosage adjustment may be needed. Consult your local health care professional for more details.
The side effects of Norvasc can be divided by the system of the organism that causes them:
- Central nervous System: Headaches, dizziness, increased fatiguability, drowsiness, mood changes, convulsions. Rare Norvasc side-effects: loss of consciousness, hyperesthesia, tremor, indisposition, insomnia, nervousness, depression, strange dreams during the night, anxiety. In rare cases Norvasc can also cause: ataxia, apathy, agitation, amnesia.
- Gastro-intestinal tract: nausea, stomach pain, jaundice. Rare side-effects: dry mouth, anorexia, vomiting, diarrhea or constipation, dyspepsia, wind, gum hyperplasia. In rare cases gastritis, increased appetite, pancreatitis.
- Cardio-vascular system: increased heart rate, feet and ankle edema, shortness of breath, face congestion. Rare Norvasc side-effects: change in heart rhythm, angina(chest pain), hypotension, ortostatic hypotension. In rare cases: increase in heart insufficiency, hypertension, migraines.
- Urogenital system Norvasc side-effects are very rare: painful impulses to urinate, change in sexual function, nocturia etc.
- Cutaneous reactions: alopecia, dermatitis, allergic reactions of deferent genesis.
- Other: Rare - changes in vision, conjunctivitis, eye pain, changes in accommodation, ringing in the ears, back pain, feeling of heat and face congestion, chills, increase in body size, nasal bleeding, increased sweatiness, thirst. Rarely: cold sweat, coughing, rhinitis, changes in taste, hyperglycemia.
During treatment body weight should be monitored. Frequent visits to the stomatologist are also required to prevent gum pains, bleeding and gum hyperplasia. Norvasc has no withdrawal syndrome but it is advised to lower the dosage steadily.
Inhibitors of microsomal oxidation can increase the concentration of Norvasc I the blood, inductors of microsomal enzymes on the other hand decrease it. There are no interactions with NSAID's.
Norvasc's action can be exponentiatiated if used with tiazid and loop diuretics. Increased hypotensive action has also been monitored in use of Norvasc with adrenoblocators and neuroleptics.
Norvasc should be used carefully with other calcium channel blockers due to possible increased manifestation of Norvasc side-effects.
If used together with Lithium preparations a possibility of increased neurotoxic manifestations exists(nausea, vomiting, diarrhea, ataxia, tremor, ringing in the ears)