CARDIO: DIURETICS, THIAZIDE + THIAZIDE-LIKE

Question 1

DIURETICS, THIAZIDE + THIAZIDE-LIKE: INDICATIONS

Answer 1

• Alternative first-line tx for HTN (CCB would otherwise be used but it is either unsuitable (eg. due to oedema) or there are features of Heart Failure
• Add on tx for HTN in patients whose blood pressure is not adequately controlled by a CCB plus an Ace Inhibitor/ARB

Question 2

DIURETICS, THIAZIDE + THIAZIDE-LIKE: MOA

Answer 2

• Inhibit the Na+/Cl- co-transporter in the DCT of the nephron

Question 3

DIURETICS, THIAZIDE + THIAZIDE-LIKE: ADVERSE EFFECTS

Answer 3

• Prevent sodium ion reabsorption from the nephron can cause Hyponatraemia
• Increased delivery of sodium to the Distal Tubule, where it can be exchanged for potassium, increases urinary potassium losses and may therefore cause hypokalaemia
• Can cause cardiac arrhythmias
• May increase plasma concentrations of glucose, LDL-cholesterol and triglycerides => Net effect on CV risk is protective
• Can cause impotence in men

Question 4

DIURETICS, THIAZIDE + THIAZIDE-LIKE: WARNINGS

Answer 4

• Hypokalaemia
• Hyponatraemia
• Precipitate acute attacks in patients with GOUT

Question 5

DIURETICS, THIAZIDE + THIAZIDE-LIKE: INTERACTIONS

Answer 5

• NSAIDs (low dose aspirin is not a concern)

- Combo of thiazides with other drugs that lower serum potassium concentration (eg Loop Diuretics) is best avoided

Question 6

DIURETICS, THIAZIDE + THIAZIDE-LIKE: EXAMPLES

Answer 6

• Bendroflumethiazide
• Indapamide
• Chlortalidone