Aspirin

CLINICAL USE

NSAID:

Analgesic and antipyretic

Prophylaxis of cerebrovascular disease or myocardial infarction

DOSE IN NORMAL RENAL FUNCTION

Analgesia: 300 mg – 1 g every 4 hours. Maximum 8 g daily in acute conditions

Prophylaxis of cerebrovascular disease or myocardial infarction: 75–300 mg daily

PHARMACOKINETICS

Molecular weight :180.2

%Protein binding :80–90

%Excreted unchanged in urine : 2 (acidic urine); 30 (alkaline urine)

Volume of distribution (L/kg) :0.1–0.2

half-life – normal/ESRD (hrs) :2–3/Unchanged

DOSE IN RENAL IMPAIRMENT

GFR (mL/MIN)

20 to 50 : Dose as in normal renal function. See ‘Other Information’

10 to 20 : Dose as in normal renal function. See ‘Other Information’

<10 : Dose as in normal renal function. See ‘Other Information’

DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

CAPD :Dialysed. Dose as in normal renal function

HD :Dialysed. Dose as in normal renal function

HDF/high flux :Dialysed. Dose as in normal renal function

CAV/VVHD :Dialysed. Dose as in normal renal function

IMPORTANT DRUG INTERACTIONS

Potentially hazardous interactions with other drugs

ACE inhibitors and angiotensin-II antagonists: antagonism of hypotensive effect, increased risk of nephrotoxicity and hyperkalaemia

Analgesics: avoid concomitant use of 2 or more NSAIDs, including aspirin – increased side effects; avoid with ketorolac – increased risk of side effects and haemorrhage

Antibacterials: possibly increased risk of convulsions with quinolonesAnticoagulants: effects of coumarins enhanced; possibly increased risk of bleeding with heparins and coumarins

Antidepressants: increased risk of bleeding with SSRIs and venlaflaxine

Antidiabetic agents: effects of sulphonylureas enhanced

Anti-epileptics: possibly increased phenytoin concentration

Antivirals: increased risk of haematological toxicity with zidovudine; concentration possibly increased by ritonavir

Ciclosporin: may potentiate nephrotoxicity

Cytotoxic agents: reduced excretion of methotrexate; increased risk of bleeding with erlotinibDiuretics: increased risk of nephrotoxicity; antagonism of diuretic effect, hyperkalaemia with potassium-sparing diuretics

Lithium: excretion decreased

Pentoxifylline: increased risk of bleeding

Tacrolimus: increased risk of nephrotoxicity

ADMINISTRATION

Reconstition

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Route

Oral

Rate of Administration

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Comments

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OTHER INFORMATION

Aspirin at analgesic/antipyretic dose is best avoided in patients with renal impairment, especially if severe

Antiplatelet effect may add to uraemic gastrointestinal and haematologic symptoms

Degree of protein binding reduced in ESRD

See how to identify renal failure stages according to GFR calculation

See how to diagnose irreversible renal disease

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