Risperidone - Adverse Effects

Adverse Effects

The severity of adverse effects often depends on the dosage. Risperidone has been associated with weight gain. Other common side effects include akathisia, sedation, dysphoria, insomnia, elevated prolactin level, low blood pressure, high blood pressure, muscle stiffness, muscle pain, tremors, hypersalivation, constipation, and stuffy nose. In addition, risperidone treatment causes photosensitivity, and patients should be warned to avoid prolonged exposure to the sun or to use effective sunscreen (SPF 15+). Other skin conditions have also been reported, including rash, xerosis (dry skin), acne vulgaris, alopecia (hair loss), and seborrhea. At high doses, skin hyperpigmentation may also occur. Irritability, aggression, sleep disorders and eating disorders are also common due to the blocking action of serotonin and dopamine that risperidone produces. Also heart arrythmia, bradycardia and heart palpitations often occur.

Many antipsychotics are known to cause hyperprolactinemia, which may lead to hypogonadism-induced osteoporosis, galactorrhoea (unexpected female breast-milk production), gynaecomastia (male breast development), irregular menstruation and sexual dysfunction.

Neuroleptic malignant syndrome has been reported with risperidone, with at least two fatal cases reported. Tardive dyskinesia, an irreversible movement disorder, has also been reported with risperidone.

Long term therapy with the drug involves a greater risk of developing early signs of Parkinson's disease as a result of the neurotransmitter imbalance of higher levels of acetylcholine and extremely low levels of dopamine. This is also seen in patients undergoing short term therapy with risperidone as well.