Timolol with bendroflumethiazide

How it works

Timolol reduces cardiac output and renin release through non-selective beta-adrenoceptor blockade, while bendroflumethiazide inhibits the distal tubular sodium-chloride co-transporter to promote natriuresis and lower vascular resistance over time.

Prescribing in practice

• As a non-selective beta-blocker, the timolol component is contraindicated in asthma and can provoke bronchospasm, and it should not be used in marked bradycardia, high-grade heart block or uncontrolled heart failure.
• Bendroflumethiazide can cause hypokalaemia, hyponatraemia, hyperuricaemia (precipitating gout) and impaired glucose tolerance, and the beta-blocker may mask the adrenergic warning signs of hypoglycaemia in people with diabetes.
• Do not stop the beta-blocker abruptly, as rebound effects can occur.

Monitoring

Monitor blood pressure, heart rate, serum electrolytes and renal function at initiation and periodically during treatment.

Counselling the patient

• Do not stop the tablet suddenly without medical advice.
• Report wheeze, marked breathlessness, or muscle cramps and weakness.
• If you have diabetes, be aware that low-glucose warning symptoms may be blunted.

Evidence & guidelines

Beta-blocker plus thiazide combinations are long-established antihypertensives, with NICE positioning beta-blockers and thiazide-like diuretics within stepwise blood-pressure management.