Wednesday, 13 July 2011

CALCIUM CHANNEL BLOCKERS

CALCIUM CHANNEL BLOCKERS

Calcium channel blockers are also called calcium antagonists or calcium blockers. They disrupt the calcium ion conduction of calcium channels.

Calcium channel blockers helps to decrease the heart rate, which can further lower the blood pressure, relieve the chest pain and control an irregular beat.

They are majorly used to treat Angina Pectoris and Hypertension, they are also employed in Cardiac Arrhythmias. 


CLASSIFICATION:

calcium channel blockers


MECHANISM OF ACTION of Calcium channel Blockers:





Calcium channel Blockers act by blocking the inward movement of calcium by binding to the L-type calcium channels in the heart and in smooth muscle of the peripheral vasculature. Calcium Channel Blockers dilate coronary arteries and peripheral arterioles, but not veins. They decrease cardiac contractility, automaticity at the SA node and conduction at the AV node. Dilation of the coronary arteries increases myocardial oxygen supply.


calcium channel blockers


USES OF CALCIUM CHANNEL BLOCKERS:

Calcium channel blockers are used for treating high blood pressure, angina, and abnormal heart rhythms, that is, atrial fibrillation and paroxysmal supraventricular tachycardia. 

They also are used for treating:

  • Pulmonary hypertension
  • Raynaud's syndrome
  • Cardiomyopathy
  • Subarachnoid hemorrhage
Calcium Channel Blockers are known to be used in prevention of migraine headaches.

SIDE EFFECTS OF CALCIUM CHANNEL BLOCKERS:

  • Abdominal pain (stomach pain)
  • Constipation
  • Drowsiness
  • Fatigue
  • Feelings of a rapidly or forcefully beating heart (palpitations)
  • Flushing or hot flashes
  • Headaches
  • Nausea
  • A sore throat
  • Swelling or water retention in the hands, feet, or lower legs.
CALCIUM CHANNEL BLOCKER DRUGS
  • Amlodipine
  • Nifedipine
AMLODIPINE

Amlodipine is a long acting calcium channel blocker. It belongs to the third generation of calcium channel blockers.

Valid Indications for Amlodipine:

  • Angina Pectoris
  • Hypertension
  • Cardiac Arrhythmia
Dose: For Hypertension or Angina- 2.5mg-10mg once daily.

Amlodipine Dosing for Adults

The recommended starting amlodipine dose in people with high blood pressure or other heart disease is amlodipine 5 mg once daily. If necessary, the dose may be increase up to amlodipine 10 mg daily. The dosage can also be decreased if any bothersome amlodipine side effects is experienced.

Amlodipine Dosing for Children

The recommended starting dose of amlodipine for children ages as young as six years old is amlodipine 2.5 to 5 mg once daily.

Contraindications:
  • Cardiogenic Shock
  • unstable angina
  • aortic stenosis
  • breast feeding
  • Pregnancy
NIFEDIPINE:

Nifedipine is a dihydropyridine calcium channel blocker. It belongs to the first generation of the calcium channel blockers.

Nifedipine rapidly lowers the blood pressure, and patients may feel dizzy or faint after taking the first few doses. Tachycardia may occur as a reaction. These problems are much less frequent in the sustained-release preparations of Nifedipine.

Valid indications of Nifedipine:
  • Long term treatment of Hypertension
  • Long term treatment of Angina Pectoris
  • Hypertensive Emergencies
Dose for Adults: The usual dose for nifedipine tablets is 10 to 20 mg three times daily. It is important to swallow the tablet whole. It should not be bitten or cut in half. Nifedipine can be taken with or without food. 

Dose for Children: The effective and safe single dose of nifedipine has been established to be 2.5mg for children weighing less than 10kg and 5mg for children weighing between 10-20kg.

Contraindications:
  • Nifedipine is contraindicated in pregnancy and in women of child-bearing potential.
  • Nifedipine should not be used by patients with a hypersensitivity to nifedipine.
  • Nifedipine should not be used in cardiogenic shock.


Active IngrediantFormStrengthPack TypePacking Style
AmlodipineTablets2.5mg, 5mg, 10mgBlister10's
Amlodipine + AtenololTablets5mg + 50mgsBlister10's
Amlodipine + EnalaprilTablets5mg + 5mgStrip10's
Amlodipine + RamiprilTablets5mg + 2.5mgBlister10's
Amlodipine + ValsartanTablets5mg + 160mg, 10mg + 160mgBlister10's
NifedipineTablets10mg, 20mgBlister10's

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