Prescribing for multiple sclerosis patients in general practice: a case-control study

Objectives: To examine the prescribing patterns for multiple sclerosis (MS) patients resident in Wales by general practitioners (GPs), compared to an age, gender and GP surgery matched control population. Methods: Anonymised data for 1996 were obtained for all patients from 24 GP practices in the all-Wales General Practice Morbidity Database (GPMD). Thi s covered 220 538 patient years at risk for 1996. Cases were selected as th ose with a Read code of MS at some point from 1993 to 1996 (therefore had c onsulted the GP at least once during this time). The controls were age, gen der and surgery matched patients randomly selected from the GPMD. Results: A total of 216 cases were identified, giving a prevalence of 97.9 per 10(5). Cases were prescribed a mean of 15 drugs each in 1996 compared t o eight drugs for controls (P < 0.0005). Compared with controls, MS patient s were prescribed significantly more laxatives, diuretics, hypnotics and an xiolytics, antidepressants, antiepileptics (mainly carbamazepine), corticos teroids, oxybutynin, vitamin B-12 and skeletal muscle relaxants (predominan tly baclofen; P < 0.05). Certain 'MS specific' drugs were not frequently pr escribed, such as cytotoxic immunosuppressants (two cases), amantadine (one case) and isoniazid (no cases). No case was prescribed medication for erec tile dysfunction. Over 80% (44/53) of corticosteroid prescriptions for MS w ere for oral prednisolone. Over one-third (39%, 9/23) of cases prescribed a corticosteroid received a 'chronic' course. Over one-third (5/14) of cours es of selective-serotonin re-uptake inhibitors (SSRI) for cases were identi fied as subtherapeutic. Conclusions: MS patients were high users of prescribed medicines, having al most twice as many prescriptions from the GP compared to controls. GP presc ribing often reflected available evidence from published controlled trials, hence cytotoxic immunosuppressants, drugs for fatigue and tremor were seld om prescribed, whereas drugs such as oxybutynin and skeletal muscle relaxan ts were frequently prescribed. However, the increased use of certain drugs compared to controls such as diuretics, vitamin B-12, hypnotics and anxioly tics were unsubstantiated in the literature. Furthermore, no published well -controlled clinical trials were found utilizing oral prednisolone or asses sing the possible therapeutic benefit of chronic courses of corticosteroids in MS, both of which were prescribed by the GP. The absence of medication for sexual dysfunction (prelicensing of sildenafil), a reportedly common MS problem, was discussed. The relatively high incidence of subtherapeutic co urses of SSRIs needs further investigation, given the increased incidence o f depression and suicide associated with MS.