Bisoprolol × Furosemide

Standard combination in heart failure and hypertension. Additive hypotensive effect; furosemide causes hypokalaemia, amplifying arrhythmia risk with concomitant QT-prolonging drugs.

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk. With additional antihypertensives: bradycardia (pulse below 60/min).

Standard combination. Check potassium and magnesium every 1–3 months. If potassium drops below 4.0 mmol/L, add a potassium-sparing diuretic (spironolactone) or potassium supplement. Check blood pressure and pulse 1–2 weeks after start.