Is weight gain a common side effect of risperidone?/nA 28-year-old woman with a known history of ps

Fråga: Is weight gain a common side effect of risperidone? A 28-year-old woman with a known history of psychosis. She delivered her third child three months ago and now has minor signs of relapse in her psychiatric disease. Within the next month she will finish breastfeeding and will then need a neuroleptic drug. Earlier treatment with perfenazin induced unwanted weight gain. Is risperidone a better alternative in this respect?

Sammanfattning: Limited data is available that deals with weight gain of risperidon as compared to other neuroleptics. It seems, however, that weight gain occurs in treatment with several new antipsychotic drugs including risperidone even though this side effect may be less pronounced for risperidone as compared to clozapine.

Svar: A similar question concerning neuroleptics and weight gain has been dealt with previously in Drugline (1). Weight gain is a common adverse effect of neuroleptic drugs.

The mechanism behind this side effect is poorly understood but there are several suggestions. Dopamine has an inhibitory effect on the beta adrenergic neurons in the so called hunger centre in the lateral hypothalamus and stimulation of this centre gives an increase in food intake. Neuroleptics block the dopaminergic system which gives an increase in food intake. Interference with the serotonergic system and inhibition of histamine receptors can also cause weight gain. Dry mouth is a common anticholinergic side effect of neuroleptics, an increased consumption of beverages is therefore common (1).

An updated Medline search gave only three relevant articles with specific information about weight gain as a side effect of risperidone.

In a meta-analysis of 11 double-blind, randomized controlled trials where the relative effectiveness and side effects of risperidone were compared with conventional neuroleptics (mostly haloperidol); weight gain was reported more frequently in risperidone-treated patients (2).

In another study of side effect profiles of traditional neuroleptic drugs and newer agents, risperidol was also found to be associated with weight gain (about 1-4 kg over the first 6 to 8 weeks) but as compared to clozapine, the weight gain was less pronounced (3).

The latter was confirmed in a direct comparison between clozapine and risperidone (4), where mean body weight was significantly greater at the end of a 6 week period of treatment with clozapine than with riperidone.

Five cases of weight gain have been reported to SADRAC (5) and 191 cases have been reported to the WHO adverse reaction register.