Midodrine (Intradialytic Hypotension)

How it works

Its active metabolite desglymidodrine selectively stimulates peripheral alpha-1 adrenoceptors, causing arteriolar and venous vasoconstriction that raises peripheral vascular resistance and blood pressure.

Prescribing in practice

• Avoid late-day dosing and dosing near recumbency because midodrine can cause marked supine hypertension; for dialysis use it is typically taken shortly before the session rather than at bedtime.
• It is contraindicated in severe organic heart disease, acute kidney injury, urinary retention, phaeochromocytoma and thyrotoxicosis.
• Dose timing must be matched to the dialysis schedule, with the last dose well before lying down, and the indication remains unlicensed in the UK.

Monitoring

Monitor supine and standing (or pre- and post-dialysis) blood pressure and watch for supine hypertension, urinary symptoms and scalp paraesthesia.

Counselling the patient

• Take your dose before sitting upright for dialysis and avoid lying flat soon afterwards.
• Report headache, pounding in the chest when lying down, or difficulty passing urine.

Evidence & guidelines

Small trials and current prescribing references support its use for symptomatic and dialysis-associated hypotension, with the SPC reflecting its limited licensed scope.