naratriptan

CLINICAL USE

5HT1 receptor agonist:Acute treatment of migraine

DOSE IN NORMAL RENAL FUNCTION

2.5 mg. Dose may be repeated after 4 hours; maximum 5 mg/24 hours

PHARMACOKINETICS

Molecular weight :371.9 (as hydrochloride)

%Protein binding :29

%Excreted unchanged in urine : 50

Volume of distribution (L/kg) :170 litres

half-life – normal/ESRD (hrs) :6/11

DOSE IN RENAL IMPAIRMENT

GFR (mL/MIN)

20 to 50 : Maximum 2.5 mg daily15–20 Maximum 2.5 mg daily<15 Use with caution – maximum 2.5 mg daily

DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

CAPD :Likely dialysability. Dose as for GFR<15 mL/min

HD :Likely dialysability. Dose as for GFR<15 mL/min

HDF/high flux :Likely dialysability. Dose as for GFR<15 mL/min

CAV/VVHD :Unknown dialysability. Dose as for GFR=15–20 mL/min

IMPORTANT DRUG INTERACTIONS

Potentially hazardous interactions with other drugs

Antidepressants: possibly increased serotonergic effects with duloxetine; increased serotonergic effects with St John’s wort – avoid concomitant use

Ergot alkaloids: increased risk of vasospasm – avoid concomitant use

ADMINISTRATION

Reconstition

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Route

Oral

Rate of Administration

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Comments

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OTHER INFORMATION

Do not take second dose at 4 hours during an attack if the first dose was ineffectualNaratriptan is excreted by glomerular filtration and active secretion into the renal tubulesInactive metabolites are renally excreted Studies in patients with impaired renal function (GFR=18–115 mL/min) showed an 80% increase in half-life and a 50% decrease in clearance compared with matched individuals with normal renal function.

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