Psychotropic Medicines in Kidney Disease

Psychotropic prescribing in kidney disease requires lower starting doses, slower titration and attention to drugs that harm the kidney or accumulate. Depression, anxiety, delirium and cognitive impairment are common in chronic kidney disease and should still be treated.

Lithium. It is excreted by the kidney, has a narrow therapeutic index and causes nephrogenic diabetes insipidus and chronic kidney disease.

Other risks. QT prolongation is more likely with hypokalaemia and hypomagnesaemia. Hyponatraemia follows SSRIs and carbamazepine. Sedatives accumulate.

Antidepressants. First choice is sertraline, which needs no renal adjustment. Alternatives are fluoxetine and mirtazapine. Avoid duloxetine when clearance is under 30 mL/min.

Antipsychotics. Quetiapine and olanzapine need little adjustment. Amisulpride, sulpiride and paliperidone are renally cleared, so use reduced doses or avoid.

Lithium. Avoid when eGFR is under 30. In stable chronic kidney disease use only by specialist decision, with lower doses and levels.

Sedatives. Short-acting agents at low doses; avoid long-acting benzodiazepines.

Special groups.

• Pregnancy: specialist advice for every agent.

• Older adults: start at half doses.

• Dialysis: sertraline, mirtazapine and quetiapine are options.

• East Africa: khat use is common in parts of the region and raises blood pressure and heart rate and can cause psychosis, so ask about it.

• Sertraline: start 25 mg once daily, increase to 50 mg after a week, maximum 200 mg daily.

• Mirtazapine: start 7.5 to 15 mg at night, maximum 45 mg, and expect higher exposure with reduced clearance.

• Paroxetine: clearance under 30, start 10 mg, maximum 40 mg daily.

• Venlafaxine: reduce the total daily dose by 25 to 50 percent when clearance is under 30 mL/min.

• Risperidone: start 0.5 mg twice daily and increase slowly.

• Amisulpride: 30 to 60 mL/min, half the dose. 10 to 30 mL/min, one third of the dose. Under 10, avoid.

• Paliperidone: maximum 6 mg daily at clearance 50 to 80, maximum 3 mg daily at 10 to 49.

• Lithium: a level of 0.4 to 0.6 mmol/L taken 12 hours after the last dose, with lower doses and longer intervals.

• Memantine: maximum 10 mg daily when clearance is 5 to 29 mL/min.

• Lorazepam: 0.5 mg as needed, with the shortest course.

Monitoring. Check creatinine, sodium, potassium, magnesium and ECG for QT drugs. For lithium, check level and eGFR every 3 months, and more often after any dose, drug or illness change.

Stop rules. Hold lithium during vomiting, diarrhoea, dehydration or acute kidney injury, and with new NSAIDs, ACE inhibitors, angiotensin receptor blockers or diuretics, which raise the level.

Referral and escalation. Seek urgent review for lithium level over 1.5 mmol/L or neurological signs. Haemodialysis is indicated for a level over 4.0 mmol/L with impaired kidney function, or reduced consciousness, seizures or life-threatening dysrhythmia at any level.

Common errors. Starting lithium or an NSAID without level monitoring, using full doses of amisulpride, missing hyponatraemia, and prescribing long-acting benzodiazepines.