Indometacin has been found to increase the peak levels of 
penicillamine by about 22%. The manufacturers warn that the concurrent use of 
NSAIDs and 
penicillamine may increase the risk of nephrotoxicity. 
 The US manufacturer specifically recommends avoiding oxyphenbutazone or phenylbutazone because these drugs are also associated with serious haematolo- gical and 
renal effects. There seems to be no reason to avoid other NSAIDS and 
penicillamine, but if problems occur bear the possibility of a drug interaction in mind.