Venlafaxine

CLINICAL USE

Antidepressant: Depressive illness Generalised anxiety disorders

DOSE IN NORMAL RENAL FUNCTION

37.5–187.5 mg twice daily XL: 75–225 mg daily Generalised anxiety disorder: 75 mg once daily

PHARMACOKINETICS

Molecular weight : 277; (313.9 as hydrochloride)

%Protein binding : 27

%Excreted unchanged in urine : 5

Volume of distribution (L/kg) : 7.5

half-life – normal/ESRD (hrs) : 5/6–8 XL: 9–21

DOSE IN RENAL IMPAIRMENT

GFR (mL/MIN)

30–50 Dose as in normal renal function 10–30 Reduce total dose by 50% and administer daily

<10 : Reduce total dose by 50% and administer daily

DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

CAPD : Not dialysed. Dose as in GFR <10 mL/min

HD : Not dialysed. Dose as in GFR <10 mL/min

HDF/high flux : Unknown dialysability. Dose as in GFR <10 mL/min

CAV/VVHD : Not dialysed. Dose as in GFR=10–30 mL/min

IMPORTANT DRUG INTERACTIONS

Potentially hazardous interactions with other drugs

Analgesics: increased risk of bleeding with aspirin and NSAIDs

Anticoagulants: effects of warfarin possibly enhanced

Antidepressants: avoid concomitant use with MAOIs and moclobemide (increased risk of toxicity); possibly enhanced serotonergic effects with duloxetine

Antimalarials: avoid concomitant use with artemether/lumefantrine

Antipsychotics: increases concentration of clozapine and haloperidol

Dopaminergics: use entacapone with caution; increased risk of hypertension and CNS excitation with selegiline – avoid concomitant use

Sibutramine: increased risk of CNS toxicity – 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

Withhold dose until after haemodialysis to minimise nausea and any other side effects May be used to treat peripheral diabetic neuropathy in haemodialysis patients; dose is up to 75 mg daily. www.medscape.com/ viewarticle/440202 An ECG is required before treatment .

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