Does Septran (Co-trimoxazole) Cause Anorexia?
Yes, co-trimoxazole (Septran) commonly causes anorexia as a gastrointestinal side effect, listed among the most frequent adverse reactions in the FDA drug label. 1
Evidence from FDA Drug Labeling
The FDA-approved prescribing information explicitly identifies anorexia as one of the most common adverse effects of co-trimoxazole:
- Gastrointestinal disturbances including anorexia, nausea, and vomiting are listed as the most common adverse effects alongside allergic skin reactions 1
- The drug label categorizes anorexia under gastrointestinal adverse reactions, which also include hepatitis, nausea, emesis, abdominal pain, diarrhea, and stomatitis 1
Clinical Context and Severity
The anorexia associated with co-trimoxazole typically presents as part of a constellation of gastrointestinal symptoms:
- Anorexia frequently occurs together with nausea and vomiting as part of the drug's gastrointestinal side effect profile 1
- In overdose situations, anorexia is specifically mentioned as one of the signs and symptoms of sulfonamide toxicity, along with colic, nausea, vomiting, and dizziness 1
Case Reports Supporting This Association
Clinical case reports document anorexia as a presenting symptom in co-trimoxazole-related adverse reactions:
- A case of acute granulomatous interstitial nephritis from co-trimoxazole presented with malaise and anorexia requiring hospitalization, demonstrating that anorexia can be a significant clinical manifestation 2
- In studies of Cyclospora infections treated with co-trimoxazole, the baseline illness included anorexia, though the drug's contribution to this symptom versus the underlying infection is difficult to separate 3
Frequency and Clinical Significance
Large-scale surveillance data provides context for how commonly this occurs:
- In a study of 3,739 adverse drug reactions reported by general practitioners, gastrointestinal disturbances (which include anorexia) were the second most frequently cited unwanted reaction (n=52) after skin reactions (n=63) 4
- Gastrointestinal disturbances appeared to occur more frequently with higher dosages of co-trimoxazole 4
Clinical Management Considerations
When prescribing co-trimoxazole, clinicians should:
- Counsel patients that loss of appetite is a common expected side effect that may occur alongside nausea 1
- Monitor for severe manifestations including persistent anorexia that could indicate more serious complications like hepatitis or bone marrow suppression 1
- Consider that anorexia may be an early warning sign of hypersensitivity reactions or organ toxicity, particularly if accompanied by other systemic symptoms 2