The FDAs Gastrointestinal Drugs Advisory Committee referred to the drugs efficacy as "modest", highlighting that the placebo brought relief on the primary outcome measure to 40–50% of women. Contraindications
Lotronexs prescribing information brochure states that alosetron should not be initiated in patients with constipation. Other contraindications are: history of chronic or severe constipation or sequelae from constipation; intestinal obstruction, stricture, toxic megacolon, gastrointestinal perforation, and/or adhesions, ischemic colitis, impaired intestinal circulation, thrombophlebitis, or hypercoagulable state; Crohns disease or ulcerative colitis; diverticulitis; severe hepatic impairment. Concomitant use of fluvoxamine is also contraindicated. Adverse effects
Alosetron was withdrawn in 2000 following the association of alosetron with serious life-threatening gastrointestinal adverse effects. The cumulative incidence of ischaemic colitis was 2 in 1000, while serious complications arising from constipation (obstruction, perforation, impaction, toxic megacolon, secondary colonic ischaemia, death) was 1 in 1000. A 1999 review performed by FDA medical officer John Senior, indicated that 27% of patients experienced constipation. The phase III trial reported constipation occurred in 30% and 3% of patients in the alosetron and placebo groups, respectively. It was cited as the most important reason for patients dropping out of the study. Mechanism of action
Alosetron has an antagonist action on the 5-HT3 receptors of the enteric nervous system of the gastrointestinal tract. While being a 5-HT3 antagonist like ondansetron, it is not classified or approved as an antiemetic.
An article published in the British Medical Journal (BMJ) noted: "By allowing the marketing of alosetron, a drug that poses a serious and significant public health concern according to its own terms, the FDA failed in its mission." Others have argued that the approval process of Lotronex was an example of regulatory capture. == References ==