Chemical Structure:
Class of drug: Thiazide diuretic
Mode of action:
Enhances diuresis by decreasing sodium (Na+) reabsorption at the distal convoluted tubule (DCT) of the nephron
Medicinal forms available:
Tablets and ‘on-request’ oral suspensions
Some brands available:
Naturetin, Aprinox
Indications and dose:
Oedema
Adult
Initially 5–10 mg once daily or on alternate days, dose to be taken in the morning, then maintenance 5–10 mg 1–3 times a week
Hypertension
Adult
2.5 mg daily, dose to be taken in the morning, higher doses are rarely necessary
Contraindications:
· Anuria
· Addison’s disease
· Hypercalcemia
· Hyponatremia
· Symptomatic hyperuricemia
· Refractory hypokalemia
Cautions:
· Diabetes
· Gout
· Systemic lupus erythematosus
· Risk of hypokalemia
· Hypotension
Interactions:
Aceclofenac – risk of acute renal failure
Allopurinol – risk of hypersensitivity reactions
Amiodarone – causes hypokalemia with increased risk of torsade de pointes
Artemether – causes hypokalemia with increased risk of torsade de pointes
Aspirin – risk of acute renal failure
Calcium – risk of hypercalcemia
Celecoxib – risk of acute renal failure
Chlorpromazine – causes hypokalemia with increased risk of torsade de pointes
Citalopram – causes hypokalemia with increased risk of torsade de pointes
Clarithromycin – causes hypokalemia with increased risk of torsade de pointes
Clomipramine – causes hypokalemia with increased risk of torsade de pointes
Diclofenac – risk of acute renal failure
Digoxin – risk of hypokalemia increase digoxin toxicity
Erythromycin – causes hypokalemia with increased risk of torsade de pointes
Fluconazole – causes hypokalemia with increased risk of torsade de pointes
Haloperidol – causes hypokalemia with increased risk of torsade de pointes
Ibuprofen – risk of acute renal failure
Mefenamic acid – risk of acute renal failure
Naproxen – risk of acute renal failure
Piroxicam – risk of acute renal failure
Quinine – causes hypokalemia with increased risk of torsade de pointes
Risperidone – causes hypokalemia with increased risk of torsade de pointes
Sildenafil – risk of hypotension and also causes hypokalemia with increased risk of torsade de pointes
Side effects/adverse effects:
· Hypercalcemia
· Electrolyte imbalance
· Hyperglycemia
· Erectile dysfunction
· Nausea
· Postural hypotension
· Dizziness
· Dry mouth
· Skin reactions
· Diarrhea
· Constipation
· Headache
· Fatigue
Pregnancy:
Thiazide and thiazide-like diuretics should not be used in pregnancy to treat gestational hypertension.
Breastfeeding:
Amount present in milk is too small to be harmful; however, large doses may suppress lactation.
Hepatic impairment:
Use with caution in mild-to-moderate impairment; avoid in severe impairment.
Renal impairment:
Avoid if eGFR is less than 30 mL/minute/1.73m2
Monitoring requirements:
Monitor electrolytes
Other drugs in class:
· Chlorothiazide
· Chlorthalidone
· Hydrochlorothiazide
· Indapamide
· Metolazone
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