When a patient is taking lithium with ACE inhibitors, ARBs, or ARNI, what is the recommended course of action?

• A. Continue without changes
• B. Avoid the combination and monitor lithium concentrations
• C. Increase lithium dose
• D. Switch to a different antihypertensive agent

Answer: (B)

Lithium is cleared by the kidneys and its level is highly sensitive to changes in renal function and sodium balance. ACE inhibitors, ARBs, and ARNI can reduce lithium clearance and increase its reabsorption in the proximal tubule, raising serum lithium levels and the risk of toxicity. This is especially important in older adults, who are more vulnerable to lithium toxicity. Therefore, the best approach is to avoid the combination when possible and use an alternative antihypertensive. If the combination is necessary, closely monitor lithium concentrations after starting or changing the dose and watch for signs of toxicity, adjusting therapy as needed. Look for symptoms such as tremor, confusion, ataxia, GI upset, or gait disturbances.