Less than 20% of clozapine-eligible patients are prescribed clozapine, in part due to patient compliance and in part due to healthcare provider concerns about side effects, such as myocarditis.
The literature was searched for studies (n=6) involving patients prescribed clozapine who developed myocarditis and cardiomyopathy.
Co-administration of clozapine and sodium valproate increased the risk of developing myocarditis (OR=3.58). Co-administration of clozapine and quetiapine, lithium, or SSRIs had no such effect.
Clozapine-induced myocarditis was not related to genetic risk, gender, ethnicity, cigarette smoking, alcohol consumption, substance abuse, or cardiometabolic disorders. Clozapine was not shown to increase the risk of cardiomyopathy.