312 Medication Responses in Chronic Fatigue Syndrome (CFS) and Non-CFS Subjects

BACKGROUND: There is a clinical perception that Chronic Fatigue Syndrome (CFS) subjects have greater drug sensitivity and “allergy” than the rest of the population. This perception was tested by assessing the symptoms associated with medication use in a group stratified by CFS status and gender. METHODS: 194 subjects answered a binary (yes-no) questionnaire (Simon GE et al, 1993) to determine if “medications” (not further subdivided by drug class) caused any of 25 symptoms from the neurological (6 symptoms); musculoskeletal (5); airways (7); gastrointestinal (5); and skin (2) systems. Subjects used our CFS Severity score to estimate the severity of fatigue and the 8 minor criteria for the previous 6 months. RESULTS: The subgroup of ALL CFS females had more frequent nausea (32% vs 13%; P = 0.013) and visual changes (19% vs 4%; P = 0.018) than ALL non-CFS females. ALL CFS males had nausea (26%; P = 0.003) and dizziness (23%; P = 0.006) compared to zero in ALL non-CFS males. However, these differences were misleading because many individuals had no symptoms, and so would not have adverse complaints or contact their physicians. Therefore, the 47% of CFS and 72% of non-CFS subjects with zero symptoms were removed. The remaining 65 CFS subjects had 5.6 symptoms (95% CI, 4.2- 7.0). The 20 non-CFS subjects had 3.5 symptoms (1.8 to 5.2; not significant by t test). Females in these subsets had no significant differences in symptoms frequencies. However, CFS males (n = 22) had more nausea (54.5% vs 0%; P = 0.067) and dizziness (50% vs 0%; P = 0.091) for non-CFS males (n = 4). CONCLUSIONS: The apparent higher prevalence of medication-related symptoms in CFS than non-CFS was biased by the large number of subjects with zero symptoms. When subjects with no complaints were excluded, there was no difference between CFS and non-CFS females, but a trend for CFS males to have had more gastrointestinal and neurologic symptoms than the non-CFS males. Overall, the equivalence of symptoms in CFS and non-CFS suggests that Multiple Chemical Sensitivity (MCS) may be an independent syndrome. These methods will direct our analysis of other irritants in this multiple chemical sensitivity questionnaire.