I have a patient with radiation-induced morphea who is beginning to respond to methotrexate. I was considering switching her to plaqenil, and then I thought that perhaps combination therapy with the two might be beneficial. Interestingly, I cannot recall ever having used the two drugs in tandem. There is very little literature about the topic. According to Epocrates no drug interactions are listed between the two agents.
The following is the abstract from the article by Haagsma and van Riel (Combination of second-line antirheumatic drugs. Ann Med 1997; 29: 169-73):
Single drug therapy is often not satisfactory in the treatment of chronic arthritis. The combination of second-line antirheumatic drugs is therefore increasingly employed. Various strategies of combining drugs can be used, starting with combinations or adding agents in case of insufficient effect of single therapy. Effective combinations have to be found empirically because lack of knowledge about pharmacodynamics and pharmacokinetics often hinders rational choices. Few controlled studies on combinations of second-line antirheumatic drugs exist, results suggesting very moderately increased efficacy and increased toxicity. Recently, results of combinations, mainly with methotrexate, have become available. Combining this agent with azathioprine did not offer advantages. Cyclosporin added to insufficiently effective methotrexate possibly has some value and antimalarials combined with methotrexate may be beneficial regarding effectivity and/or toxicity. Methotrexate added to insufficiently effective sulphasalazine seems to be better than methotrexate alone, although this combination when used from the start of the therapy was disappointing. Triple therapy of the latter combination together with hydroxychloroquine turned out to be superior to single methotrexate and to the combination of sulphasalazine and hydroxychloroquine. Surprisingly, the toxicity of these combinations was mainly comparable to single therapy. In conclusion, combinations of second-line antirheumatic drugs have a role, although not yet clearly defined, in the therapy of chronic arthritis.
Does anyone have clinical experience with this combination? If so, was effective? Was it well tolerated or were there any unexpected adverse reactions?