High prevalence of potential drug-drug interactions for psoriasis patients prescribed methotrexate or cyclosporine for psoriasis: associated clinical and economic outcomes in real-world practice.
BACKGROUND
Methotrexate (MTX) and cyclosporine (CYC) may adversely interact with common medications in patients with psoriasis.


OBJECTIVE
Our purpose was to investigate the prevalence and outcomes of MTX/CYC polypharmacy.


METHODS
We evaluated rates of events that may be associated with drug-related toxicity, health care resource utilization and costs for patients with psoriasis in the Ingenix(R) Impact National Managed Care Database (1999-2007) who were exposed or not exposed to potential drug-drug interactions.


RESULTS
Among 4,583 (57.6%) exposed and 3,372 (42.4%) nonexposed patients, nonsteroidal anti-inflammatory drugs and antibiotics were the most common drugs with potential interactions. The exposed patients had significantly greater risks of developing renal [adjusted odds ratio (OR): 2.58; p = 0.0145], gastrointestinal (OR: 1.36; p = 0.0197) and pulmonary events (OR: 1.20; p = 0.0470), and significantly greater health care resource utilization (e.g. OR for inpatient and emergency department visits: 1.47; p < 0.0001) and costs (adjusted incremental cost: USD 1,722; p < 0.0001).


CONCLUSIONS
MTX/CYC polypharmacy is prevalent in patients with psoriasis and associated with significant risks.
Hôpital Cantonal Universitaire de Genève, Geneva, Switzerland. jean.saurat@medecine.unige.ch
Jean-Hilaire
JH
Saurat
Annie
A
Guérin
Andrew P
AP
Yu
Dominick
D
Latremouille-Viau
Eric Q
EQ
Wu
Shiraz R
SR
Gupta
Yanjun
Y
Bao
Parvez M
PM
Mulani
D000368:Aged; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000627:therapeutic use; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects / Q000191:economics / Q000627:therapeutic use*; D016572:Cyclosporine / Q000009:adverse effects / Q000191:economics / Q000627:therapeutic use*; D004347:Drug Interactions; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects / Q000191:economics / Q000627:therapeutic use*; D008297:Male; D008329:Managed Care Programs / Q000191:economics; D008727:Methotrexate / Q000009:adverse effects / Q000191:economics / Q000627:therapeutic use*; D008875:Middle Aged; D015995:Prevalence; D011565:Psoriasis / Q000188:drug therapy* / Q000191:economics; D012176:Retinoids / Q000009:adverse effects / Q000627:therapeutic use
D000900:Anti-Bacterial Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D007166:Immunosuppressive Agents; D012176:Retinoids; D016572:Cyclosporine; D008727:Methotrexate