Moderate
Hydrochlorothiazide × Sertraline
Thiazide diuretics×Selective serotonin reuptake inhibitors (SSRIs)
Mechanism
Thiazides are one of the most common drug causes of hyponatraemia in older patients via SIADH-like mechanism and natriuresis. SSRIs (sertraline) add a SIADH-like effect. Additive risk.
Symptoms
Headache, nausea, confusion, drowsiness; severe cases: seizures. Develops slowly over 1–2 weeks and is often missed in older patients.
Management
On the combination, check sodium at 2 and 4 weeks after starting sertraline or the thiazide, then every 6 months. If sodium falls below 130 mmol/L, consider switching sertraline to mirtazapine or agomelatine, or replacing the thiazide with indapamide (lower hyponatraemia risk).
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Sources
- Lexicomp: Lexicomp Drug Interactions (2024)– Wolters Kluwer Clinical Drug Information, Inc. Lexi-Interact Online, 2024
- AGS: American Geriatrics Society Beers Criteria for Potentially Inappropriate Medication Use (2023)– By the 2023 American Geriatrics Society Beers Criteria Update Expert Panel. AGS Beers Criteria for Potentially Inappropriate Medication Use in Older Adults. J Am Geriatr Soc 2023;71(7):2052-2081.