Analgesic effect and fecal blood loss induced by antrafenine. A double-blind comparison with aspirin

Forty-two patients admitted to hospital because of radicular neuralgia were the subjects of randomized double blind clinical trial lasting 6 days in which the effects were compared of 3 g/d aspirin and 600 mg/d antrafenine. The comparison was aimed at the following parameters: analgesic effect, the volume of occult blood loss as determined by radioisotopic tracing during the last 3 days of treatment and finally, clinical tolerance. It transpired that the potency, delayed and duration of effectiveness of the 2 products were not different but occult blood loss was significantly lower with antrafenine (2.18 ± 1.32 ml/72 h) than with aspirin (10.36 ± 9.76 ml/72 h) (p < 0.001). Occult blood loss was held within normal limits (< 6 ml/72 h) by all 21 patients on antrafenine whereas this was the case for only 7 of the patients on aspirin. A study of the clinical tolerance showed that gastralgia predominated with aspirin (6/12) whereas with antrafenine it was headaches (6/21) and nausea (3/21).