Antipsychotic agents seizures

Antipsychotic drugs include the older phenothiazines and butyrophenones, as well as newer atypical drugs. All of these can cause CNS depression, seizures, and hypotension. Some can cause QT prolongation. The potent dopamine D2 blockers are also associated with parkinsonian-like movement disorders (dystonic reactions) and in rare cases with the neuroleptic malignant syndrome, characterized by "lead-pipe" rigidity, hyperthermia, and autonomic instability (see Chapter 29 Antipsychotic Agents Lithium). 

Seizures Bupropion is associated with a dose-related risk of seizures. Discontinue bupropion and do not restart in patients who experience a seizure while on treatment. Use extreme caution when bupropion is administered to patients with a history of seizure, cranial trauma, or other predisposition(s) toward seizure, or prescribed with other agents (eg, antipsychotics, other antidepressants, theophylline, systemic steroids) that lower seizure threshold. 

Clonazepam. Clonazepam is marketed primarily for petit mal variant, myoclonic, and akinetic seizures. It also has had wide psychiatric application, including the treatment of acute mania or other agitated psychotic conditions, usually in combination with lithium or antipsychotics. The literature on clonazepam s efficacy for acute mania is based on the work of Chouinard (120) and coworkers who compared this agent with placebo or standard treatments for acute mania. As noted earlier, however, another group from Montreal found that comparable doses of lorazepam were more effective than clonazepam for acute mania (119). 

Tricyclic antidepressants lower the seizure threshold and should therefore be used with caution with other agents that can also lower seizure threshold, such as antipsychotic drugs (164). 

These findings have important implications for the treatment of bipolar affective disorder. Some agents used to treat partial-complex seizures such as carbamazepine and various valproate formulations have been found to be effective in bipolar affective disorder (Bowden 1995). One such agent, divalproex, is now the most commonly prescribed antimanic agent. These agents may be more effective in subtypes of mania that are not lithium responsive. As noted earlier, African Americans are more often prescribed antipsychotics. Poor tolerance of lithium maybe a factor. Improving access to alternatives to lithium may reduce the need for antipsychotics in some African Americans with mania. 

Seizure-inducing agents Bupropion should be administered cautiously to patients taking medications or undergoing treatment regimens that may lower the seizure threshold (e.g. antidepressants, antipsychotics, systemic corticosteroids, and theophylline. 

Treat coma (see p 19), shock (p 16), and arrhythmias (pp 13-15) if they occur. Because of the association of arsenic with prolonged QT intervals, avoid quinidine, procainamide, and other type la antiarrhythmic agents. Phenothiazines should not be given as antiemetics or antipsychotics because of their ability to prolong the QT interval and lower the seizure threshold. 

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