Tachycardia risperidone

There are two classes of a-adrenergic receptors, aj and a2. Agents with the greatest affinity for aj blockade are chlorpromazine, thioridazine, and risperidone. There are no known beneficial effects associated with a -adrenergic receptor antagonism. However, aj-adrenergic receptor blockade can lead to hypotension, dizziness, and reflex tachycardia (Table 26.2). a2 Blockade is modest for most agents except for risperidone and clozapine. As with aj receptors, there are no benefits that have yet to be associated with a2 receptor... 

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. 

One of two children aged 29 and 23 months with autistic disorder developed a persistent tachycardia and dose-related QTC interval prolongation while taking risperidone (58). 

A 41-year-old man who took risperidone 270 mg developed a prolonged QTC interval (480 ms) and sinus bradycardia (44/minute), without hemodynamic compromise. After 9 hours, he had episodes of asymptomatic supraventricular tachycardia with a maximum frequency of 150/minute. After 30 hours he was in sinus rhythm with a normal QTC interval (360 ms). 

A 15-year-old who took 110 mg of risperidone in a suicide attempt developed only transient lethargy, hypotension, and tachycardia without any other significant effects (237). 

Of 524 inquiries received by the National Poisons Information Service concerning new neuroleptic drugs over 9 months, only 45 cases involved overdose with a single agent (olanzapine, n — 10 clozapine, n — 8 risperidone, n — 10 sulpiride, n = 16) (503). There were no deaths or cases of convulsions. Cardiac dysrhythmias occurred only with sulpiride. Symptoms were most marked with clozapine most patients had agitation, dystonia, central nervous system depression, and tachycardia. Most of the patients who had taken risperidone were asymptomatic. 

A post hoc analysis of 64 studies with risperidone and paliperidone assessed risk of sudden death, cardiovascular and cerebrovascular events [33" ]. The overall risk was significantly increased compared to placebo for adverse events including syncope, tachycardia, palpitations, oedema peripheral, dysarthria and transient ischaemic attack. 

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