EXTRAPYRAMIDAL SIDE-EFFECTS AND TOLERABILITY OF RISPERIDONE - A REVIEW

The effectiveness of conventional neuroleptics in schizophrenia is oft en limited by extrapyramidal side effect's (EPS), which are known to c ontribute to poor compliance and relapse. However, there is now eviden ce that drugs that block 5-HT2 receptors as well as D2 receptors have better EPS profiles. Risperidone has these pharmacologic properties. I n two large clinical trials, risperidone (2, 6, 10, 16 mg/day or 4, 8, 12, 16 mg/day) was compared with either placebo and haloperidol (20 m g/day) or risperidone (1 mg/day) and haloperidol (10 mg/day). Extrapyr amidal side effects were assessed using the Extrapyramidal Symptom Rat ing Scale and by recording the use of anticholinergic medication. Othe r adverse effects were assessed using the UKU Side Effects Scale. In b oth studies, the severity of EPS in the risperidone groups was signifi cantly less than in the haloperidol group. In the placebo-controlled s tudy, doses of 2 and 6 mg/day of risperidone produced no worse EPS tha n placebo. Other side effects were minor, and included brief hypotensi on (mediated via alpha-blockade) and weight gain. Overall, risperidone at antipsychotic doses was better tolerated than haloperidol.