Which medication combination should generally be avoided due to potential increased side effects?

The combination of ACE inhibitors and ARBs (Angiotensin II Receptor Blockers) is typically advised against due to the heightened risk of side effects, particularly renal impairment and hyperkalemia. Both drug classes work on the renin-angiotensin-aldosterone system (RAAS) but at different sites; using them together can lead to an additive effect that may significantly lower blood pressure or adversely affect kidney function. This is particularly concerning in patients with conditions that necessitate careful blood pressure and renal function management.

The other combinations listed, while they also require monitoring, generally do not have the same degree of risk for severe adverse effects when used together. Beta-blockers and diuretics can be used concurrently, though their effects need to be carefully monitored. Likewise, calcium channel blockers and thiazides are often combined to manage hypertension, and loop diuretics with potassium-sparing diuretics can be used to mitigate potassium loss, though supervision is needed to maintain electrolyte balance. However, the dual blockade of the RAAS through the combination of ACE inhibitors and ARBs presents a notably increased risk profile that justifies avoidance in most clinical scenarios.