Adverse drug reactions antipsychotics

Sekine, Y., Rikihisa, T, Ogata, H., Echizen, H., and Arakawa, Y. (1999) Correlations between in vitro activity of antipsychotics to various central neurotransmitter receptors and clinical incidence of their adverse drug reactions. Eur J Clin Pharmacol 55 583— 587. 

The relation between neuroleptic drug therapy and myocarditis and cardiomyopathy has been examined using the international database on adverse drug reactions run by the World Health Organization (152). Myocarditis and cardiomyopathy were reported rarely as suspected adverse drug reactions, and accounted for under 0.1% (n = 2121) of almost 2.5 million reports. The association of clozapine with those adverse reactions was statistically significant (231 reports out of 24 730), as was the association with other antipsychotics (89 of 60 775). 

The selection of appropriate antipsychotic treatment is often a trial-and-error procedure, with multiple failed trials required before achieving an acceptable balance between symptom management and tolerability of adverse effects. This is problematic because it increases the risk of adverse drug reactions and delays symptom management, worsening long-term treatment outcomes [2]. 

Americans (26). It is involved in the metabolism of approximately 30-40 commonly used drugs. Millions of patients with compromised metabolism are thus at risk of adverse drug reactions when prescribed drugs that are CYP2D6 substrates. Many such drugs are used for treating psychiatric (such as antidepressants and antipsychotics) and cardiovascular diseases (such as j8-blockers and antiar-rhythmics), where the therapeutic window can be narrow and side effects common. 

The nurse explains any adverse reactions that may occur with a specific antipsychotic drug and encourages the patient or family members to contact the primary health care provider immediately if a serious drug reaction occurs. 

List the uses, general drug actions, general adverse reactions, contraindications, precautions, and interactions associated with the administration of the antipsychotic drugs. 

Discuss ways to promote an optimal response to therapy, how to manage common adverse reactions, and important points to keep in mind when educating patients about the use of the antipsychotic drugs. 

Agranulocytosis Because of a significant risk of agranulocytosis, a potentially life-threatening adverse reaction, reserve clozapine for use in the treatment of severely ill schizophrenic patients who fail to show an acceptable response to adequate courses of standard antipsychotic drug treatment because of insufficient effectiveness or the inability to achieve an effective dose due to intolerable adverse effects from those drugs. Consequently, before initiating treatment with clozapine, it... 

Tardive dyskinesia is a late-occurring syndrome of abnormal movements of the face and tongue with widespread choreoathetosis. It is the most serious adverse effect of the antipsychotic drugs. It can be expected to occur in 20 to 40% of chronically treated patients there is no established treatment, and reversibility may be limited. These reactions are more frequent and severe in the elderly. 

One common denominator of all antipsychotics is the biockade of centrai dopamine (DA) receptors. As a result, extrapyramidal reactions, particularly parkinsonian symptoms, are a major adverse effect of many of these drugs, as well as an important clue to their mechanism of action. True Parkinson s disease is caused by a DA deficiency in the nigrostriatal system. Further, crystallographic data have demonstrated that CPZ s molecular configuration is similar to that of DA, which could explain its ability to block this neurotransmitter s receptors. Drugs with similar structures that do not block DA receptors (e.g., promethazine, imipramine) do not have antipsychotic activity. Another example is the isomer of flupenthixol, which blocks DA receptors is an effective antipsychotic, but the isomer that does not is ineffective (7). The other family of dopamine receptors, D and Dg, have not yet been implicated in psychosis. 

Tardive or withdrawal dyskinesias, some transient but others irreversible, seen in 8%-51% of antipsychotic-treated children and adolescents, mandate caution regarding casual use of these drugs. Tardive dyskinesia has been documented in children and adolescents after as brief a period of treatment as 5 months and may appear even during periods of constant medication dose. Cases of tardive dyskinesia have been reported in youths treated with risperidone, indicating that atypical antipsychotics may also cause this serious adverse reaction. 

In a study of 1230 patients with initially unexplained cardiomyopathies, lithium was implicated in one case (114). Using a data-based mining Bayesian statistical approach to the WHO database of adverse reactions to examine antipsychotic drugs and heart muscle disorders, a significant association was found between lithium and cardiomyopathy, but not myocarditis (146). The authors acknowledged that further study is needed to determine if the association is causal. 

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