Could risperidone cause thrombocytopenia and bleeding as an adverse effect?/nA 53-year-old woman wi

Fråga: Could risperidone cause thrombocytopenia and bleeding as an adverse effect? A 53-year-old woman with bipolar disorder has been treated with lithium for 18 years. A year ago, risperidone (1.0 mg daily) was introduced together with lithium for six months. Risperidone treatment was stopped for another 6 months but was then reintroduced at the same dose. After 5 to 6 weeks, the patient developed petechiea, mucosal bleeding in the mouth, and decreased platelets 4 E-9 (normal level 150 to 400 E-9).

Sammanfattning: Thrombocytopenia and bleeding disorders has been described as uncommon adverse effects of risperidone. A number of case reports about different bleeding disorders are found in the Swedish adverse reaction register the WHO adverse drug register.

Svar: A thorough literature search in medical databases and reference literature revealed only sparse information about bleedings and decreased platelets as side effects of risperidone.

Bleeding disorders, such as epistaxis, purpura, hemorrhage, and thrombocytopenia, have been reported as rare side effects of risperidone (1,2), but no mechanism behind these effects could be found in the literature.

Two cases of slightly subnormal platelets values (TPK 147 and 130 E-9, respectively) and single cases of epistaxis and pancytopenia (TPK 96 E-9), respectively, have been reported to the Swedish adverse reaction register (Swedis) following risperidone treatment (3). In the WHO adverse drug reaction register (Intdis) (4) there are 52 reports on epistaxis, one report on oral hemorrhage, and 12 reports on decreased prothrombin values.

The producer has no further information about bleeding disorders as a side effect of risperidone (5).

Thus, the present case is the first in which severe thrombocytopenia has been reported in connection with risperidone treatment and has been reported to the Swedish adverse drug reactions advisory committee.