Effects of nonsteroidal anti-inflammatory drugs on post-operative renal function in normal adults

Nonsteroidal anti-inflammatory drugs (NSAIDs) can play a major role in the management of acute pain in the peri-operative period. However, there there are conflicting views on whether NSAIDs are associated with adverse renal effects.

The primary objective of this review was to determine the effects of NSAIDs on post-operative renal function in adults with normal pre-operative renal function.

Electronic searches for relevant randomised and quasi-randomised controlled trials in Cochrane Controlled Trials Register, MEDLINE and EMBASE were performed. Attempts were also made to identify trials from citation lists of relevant trials, review articles and clinical practice guidelines. Hand-searching of conference abstracts published in major anaesthetic journals was also performed.

The inclusion criteria were randomised or quasi-randomised comparisons of individual NSAIDs with either each other or placebo for treatment of post-operative pain, with relevant post-operative renal outcome measures, in adult surgical patients with normal renal function.

Of the 14 trials that fulfilled the selection criteria for this review, eight trials were relevant with sufficient data for meta-analysis. The data was extracted independently by two reviewers. The primary outcome measure was creatinine clearance within the first two days after surgery. Secondary outcome measures included serum creatinine, urine volume, urinary sodium level, urinary potassium level, fractional excretion of sodium, fractional excretion of potassium, need for dialysis and need for diuretic or dopamine treatment for renal insufficiency. Weighted mean differences for continuous outcomes and relative risk for dichotomous outcomes were estimated.

As a group, NSAIDs reduced creatinine clearance by 18ml/min (95%CI: 6 to 31) and potassium output by 38mmol/day (95%CI: 19 to 56) on the first day after surgery compared to placebo. Serum creatinine clearance increased on the second day after surgery by 15umol/L (95%CI: 2 to 28) compared to placebo. No significant reduction in urine volume during the early post-operative period was found. There was no significant difference in serum creatinine in the early post-operative period between patients receiving ketorolac and diclofenac in one trial. No cases of post-operative renal failure requiring dialysis were described.

NSAIDs caused a clinically unimportant transient reduction in renal function in the early post-operative period in patients with normal pre-operative renal function. NSAIDs should not be withheld from adults with normal pre-operative renal function because of concerns about post-operative renal impairment.