Mô tả
Hydrochlorothiazide may reduce renal clearance of memantine through alkalinisation of urine, as memantine elimination is pH-dependent; the clinical impact is generally minor.
Cơ chế
Memantine is a weak base; alkaline urine (caused by carbonic anhydrase inhibition-like effects of some diuretics or alkalosis) promotes ionisation in favour of the unionised form, reducing tubular reabsorption and potentially altering systemic exposure.
Ý nghĩa lâm sàng
Pharmacokinetic modelling suggests urine pH changes of 1–2 units could alter memantine AUC; clinical case reports of toxicity are absent, but routine monitoring is advisable.
Xử trí
No dose adjustment required; be aware that drugs causing significant urine alkalinisation could alter memantine levels in patients with renal impairment.