Relistor is a new drug for treatment of opioid-induced constipation in advanced illness patients who are receiving palliative care when response to usual laxative therapy has not been sufficient.
The drug is administered subcutaneous and dosed after weight every second day.
Two randomized, double blinded, placebo controlled studies describes the effect of methylnaltrexone on terminally ill patients with opioid-induced constipation. The primary endpoints were the number of patients, who had laxation within 4 hours after the first study dose. The absolute effect difference between the treatment with methylnaltrexone and placebo was respectively 32,9 % and 48,2 %, which is equivalent to NNT (number needed to treat) on 2-3. Because of the method used to handle missing values and the number of discontinued patients, the results are mortgaged with a certain amount of uncertainty.
The side effects is primary gastrointestinal and the most frequent is abdominal pain and diarrhoea.
The price of one dose of Relistor is 334,95 Dkr., which is more expensive than the oral laxatives on the market.
IRF states that Relistor should not be the first drug of choice in treatment of opioid-induced constipation because of the high price and the missing comparative studies with oral laxatives. Relistor can with advantage be used as supplement when response to usual laxative therapy has been insufficient.
Relistor was marketed the 11th of August 2008, and is not under the rules of general reimbursement.