Amlodipine (AM) is an antihypertensive drug (Drug used to lower blood pressure) of the calcium channel blocker class (CCB).
The drug acts by closing voltage gated calcium ion channel that are responsible for increase in blood pressure.
USES
- Hypertension
- Coronary Artery Disease
- Stable angina
- Vasospastic angina
- Stroke
- Chronic Kidney Disease
- Raynaud’s phenomenon
DOSAGE FOR AMLODIPINE
Dosage forms available:
- Tablet: 2.5 mg, 5 mg, 10 mg
- Capsule: 5 mg
- Oral solution: 1 mg/ml, 2 mg/ml
- Several combination doses of AM with other antihypertensive drugs and anti-lipid drugs exist:
a) Amlodipine-Atorvastatin
b) Amlodipine-aliskiren-HCTZ
c) Amlodipine-Benazepril
d) Amlodipine-Olmesartan
e) Amlodipine-Telmisartan
f) Amlodipine-Metoprolol
Dosage guidelines:
- Stable angina: 5 mg – 10 mg once daily depending on severity of symptoms & condition.
- Hypertension: Initially 2.5 – 5 mg once daily, can be increased to 10 mg once daily.
- Reynaud’s phenomenon: 5 mg once daily for 4 weeks.
Missed dose: Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
Overdose:
a) Detoxification by activated charcoal.
b) High doses of IV insulin with glucose infused.
c) IV infusion of calcium gluconate or calcium chloride is a potential antidote.
d) Management of low blood pressure by norepinephrine.
e) Lipid emulsion
SIDE EFFECTS
- Swelling (edema)
- Excess fluid in the lungs (pulmonary edema)
- Headache
- Fatigue & dizziness
- Palpitations
- Nausea
- Flushing
- Abdominal pain
- Sleepiness
- Male sexual disorder
- Itching & skin rash
- Muscle cramps & weakness
ADVERSE EFFECTS ARISING FROM AMLODIPINE
- Peripheral edema
- Increased intracranial pressure
- Slow heart rate
- Low blood pressure
- Reflex tachycardia
- Shortness of breath
- Seizure
- Gingival overgrowth (Increase in size of gums)
- Low blood calcium levels
- Ringing in the ear
- Worsening of coronary artery disease symptoms
- Heart attack.
PRECAUTIONS & CONTRAINDICATIONS
AM is contraindicated & precaution is advised in patients with following conditions:
- Aortic stenosis
- Heart failure
- Hepatic impairment
- Hypertrophic cardiomyopathy (HCM)
- Obstructive CAD
- Cardiogenic shock
- Unstable angina
- Low blood calcium/Calcium deficiency.
INTERACTIONS OF AMLODIPINE
- Amlodipine in presence of amphetamines has a diminished antihypertensive effect, i.e, its therapeutic effects are cancelled out.
- Some antifungals like itraconazole may enhance the toxic effect of CCBs.
- Barbiturates may increase the metabolism of CCBs
- The drug may diminish the therapeutic effects of clopidogrel.
- CCBs may increase the hypotensive effects of levodopa.
- Macrolide Antibiotics, may decrease the metabolism of Calcium Channel Blockers.
- Calcium Channel Blockers may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents (Nondepolarizing).
- When more than 20 mg of simvastatin, a lipid-lowering agent, is given with amlodipine, the risk of myopathy increases.
- Amlodipine given with sildenafil can lead to decrease in blood pressure.
IN PREGNANCY, BREAST FEEDING & CHILDREN
- Pregnancy: The drug can cross the placenta and therefore use in pregnancy is not recommended.
- Breast Feeding: Safety of use of CCBs in breast feeding mothers is not established.
- Children: AM is used in children above the age of 6 in low titrated doses.