Amlodipine and Hydrochlorothiazide

Calcium Antagonist · Calcium antagonist/Thiazide diuretic

Indications

Hypertension. Myocardial ischaemia.

Dosage

Hypertension/Myocardial ischaemia: Adults: Usually initial dose of 1 tab once daily, may be increased to a max daily dose of 2 tab. Children: Not recommended.

Adverse Effects

Amlodipine: Headache, oedema, fatigue, nausea, flushing and dizziness, rash, gingival hyperplasia. Rarely, alopecia, pruritus, angioedema, palpitations, dyspnoea, abdominal pain, back pain, dyspepsia, muscle cramps, asthaenia, somnolence, altered bowel habit, myalgia, arthralgia, peripheral neuropathy, pancreatitis, mood changes, dry mouth, increased micturition, hyperglycaemia, impotence, sweating, syncope, thrombocytopenia, vasculitis, visual disturbances, palpitation, GI upset. Hydrochlorothiazide: Anorexia, epigastric distress.

Risk Factor (Pregnancy/Lactation)

Pregnancy: Contraindicated in pregnancy. Lactation: Contraindicated or not recommended. Contraindications: Amlodipine: Cardiogenic shock, aortic stenosis, unstable angina, left ventricular outflow obstruction, severe hypotension, unstable heart failure following MI. Hypersensitivity to dihydropyridines. Hydrochlorothiazide: Anuria, renal decompensation. Precautions: Amlodipine: Within one month of MI. Impaired hepatic function. Hypertensive crisis, heart failure. Elderly. Hydrochlorothiazide: Avoid in severe renal disease. Gout, diabetes, patients with moderate to high cholesterol concentrations.

Interactions

Amlodipine: Azole antifungals, erythromycin, cyclosporin, sildenafil, rifampicin, CYP3A4 inhibitors and inducers, dantrolene, simvastatin, tacrolimus, other antihypertensives, grape fruit juice. Hydrochlorothiazide: Beta-blockers, ACE inhibitors, neuromuscular blocking agents, oral hypoglycaemics, NSAIDs.

Pharmacokinetics

AMLODIPINE: Onset of action: Antihypertensive effect: Significant reductions in blood pressure at 24-48 hrs after first dose. Duration: Antihypertensive effect: At least 24 hrs. Discontinuation after 6-7 wks of treatment: Duration extends to at least 72 hrs. Absorption: Well absorbed. Metabolism: Hepatic. Bioavailability: 64%-90%. Half-life elimination: Terminal (biphasic): 30-50 hrs. Time to peak, plasma: 6-12 hrs. Excretion: Urine. HYDROCHLOROTHIAZIDE: Onset of action: Diuresis: Infants: 2-6 hrs. Adults: Approx. 2 hrs. Peak effect: 4-6 hrs. Duration: Infants: 8 hrs. Adults: 6-12 hrs. Absorption: Well absorbed, absorption is decreased in patients with CHF. Metabolism: Not metabolized. Bioavailability: 65%-75%. Half-life elimination: Approx. 6-15 hrs. Time to peak: Approx. 1-5 hrs. Excretion: Urine.

Compiled by Healify Pharmacy from published drug references. How we compile it →

Always consult a pharmacist or doctor.