Risperidone mouth

A child with attention-deficit hyperactivity disorder [ADHD] and conduct disorder is treated with 45 mg/d of methylphenidate and 2 mg/d of risperidone. A new diagnosis of complex partial seizures is made and the child is started on carbamazepine. About 10 days after the initiation of carbamazepine, the child develops withdrawal dyskinesias of mouth and tongue. After discontinuation of carbamazepine, the movements last for 1 week. 

One variant of TD called rabbit syndrome is characterized by fine, rapid, rhythmic movements along the vertical axis of the mouth. A recent review found 11 cases associated with atypicals, mostly risperidone (Dell Osso et al., 2007). All of the FDA-approved atypical neuroleptic labels carry the same class warning as the older neuroleptics. 

Clozapine has also been compared with risperidone in 60 treatment-resistant patients with schizophrenia in India (16). There was clinical improvement (a more than 20% reduction from baseline PANSS scale scores) in 80% of the clozapine-treated patients and 67% of the risperidone-treated patients. The predominant adverse effects with clozapine (n = 30) were tachycardia (77%), hypersalivation (60%), sedation (60%), weight gain (43%), and constipation (30%) one patient had a seizure. The adverse effects of risperidone (n = 30) were constipation (50%), dry mouth (47%), weight gain (43%), akathisia (37%), insomnia (33%), tachycardia (30%), and impotence (27%). The final mean daily doses after 16 weeks of treatment were 343 mg for clozapine and 5.8 mg for risperidone. 

In a double-blind, placebo-controlled study of the addition of low-dose risperidone (mean dosage 2.2 mg/day) to a 5-HT re-uptake inhibitor in refractory obsessive-compulsive disorder in 70 adults, 18 of 20 risperidone-treated patients had at least one adverse effect (37). The adverse effects in both groups included sedation (n = 17 for risperidone, n = 8 for placebo), increased appetite (6 and 3), restlessness (6 and 6), and dry mouth (5 and 5). 

In a 9-week double-blind, randomized, placebo-con-trolled study, subjects were assigned to either risperidone (n = 14, 13 men and 1 woman mean age 42 years dose titrated upwards up to 2 mg/day) or to placebo (n = 9, 6 men and 3 women mean age 39 years) (43). Adverse effects were reported in seven subjects who took risperidone, including dry mouth, tiredness, weakness, reduced sexual arousal and delayed ejaculation, and a mild dys-tonic reaction. However, five placebo-treated subjects also reported adverse effects, which might have been due to the strong tendency of these patients to become somatically preoccupied. There were no group differences in dropout rates due to adverse effects. 

A 13-year-old boy developed mild mouth movements, neck twisting, and intermittent upward gaze approximately 2 weeks after withdrawal of risperidone (1.5 mg and then 0.5 mg) (96). 

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