[Interaction between non-steroidal anti-inflammatory agents and lithium salts]

Since the first observation in 1978, it has been clearly established that the non-steroidal anti-inflammatory drugs (NSAIDs) interfere with the pharmacokinetics of lithium: by reducing urinary clearance of the metal, they can raise the plasma lithium level and thus lead to intoxication. Among the NSAIDs available in France, this interaction has been reported with phenylbutazone (Butazolidine, Carudol), diclofenac (Voltarène), indomethacin (Indocid) and its antalgic derivative clomethacin (Dupéran), ketoprofen (Profenid), mefenamic acid (Ponstyl), niflumic acid (Nifluril) and piroxicam (Feldène). This interaction does not occur with aspirin; this exception suggests that the inhibition of prostaglandins synthesis is not the mechanism responsible for the decrease in the urinary elimination of lithium linked with an increase in its tubular reabsorption. In practice, in view of the growing diffusion of NSAIDs, it is necessary to inform all patients under lithium treatment of the risk of interaction resulting from their use.