Volume of distribution (L/kg)       :No data
half-life – normal/ESRD (hrs)      :25 minutes (3 hours for active metabolite)/increased (9 for active metabolite)
DOSE IN RENAL IMPAIRMENT
GFR (mL/MIN)
20 to 50     : Dose as in normal renal function
10 to 20     : Dose as in normal renal function. Start with a lower dose and titrate according to response
<10           : Dose as in normal renal function. Start with a lower dose and titrate according to response
DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES
CAPD                :Dialysed. Dose as in GFR
<10           : mL/min
HD                     :Dialysed. Initial dose, 2.5 mg if 70 kg.
HDF/high flux   :Dialysed. Initial dose, 2.5 mg if 70 kg.
CAV/VVHD      :Dialysed. Dose as in GFR=10–20 mL/min
IMPORTANT DRUG INTERACTIONS
Potentially hazardous interactions with other drugsRisk of arrhythmias if given with volatile anaestheticsRisk of arrhythmias and hypertension if given with tricyclic antidepressants and MAOIsRisk of severe hypertension if given with beta-blockersOther drugs which increase blood pressure: enhanced hypertensive effect
ADMINISTRATION
Reconstition
–
Route
Oral
Rate of Administration
–
Comments
Take last dose at least 4 hours before bed
OTHER INFORMATION
Metabolised to an active metabolite (desglymidodrine)After dialysis only 15% of drug remaining, so effectively removed by dialysisHypertension post dialysis is not a problem because drug is dialysed outPeak levels occur 30 minutes after administration (60 minutes for active metabolite) so give 30 minutes before dialysis – avoid in patients with active coronary ischaemia93% bioavailability For haemodialysis patients, start at a low dose and increase to a maximum of 30 mg; a second dose can be given midway through dialysis (maximum dose 10 mg)
Contraindicated in severe organic heart disease, urinary retention, phaeochromocytoma and thyrotoxicosis