When clozapine hit the market in 1989, it was clearly different from the older antipsychotic drugs such as chlorpromazine (Thorazine). It didn’t cause tremors and rigidity, the so-called extrapyramidal symptoms (EPS) that resemble Parkinson’s disease. However, clozapine (Clozaril) had a problem: It increased the risk of causing a potentially fatal blood disorder, agranulocytosis. Zyprexa (olanzapine), which appeared in 1996, resembled clozapine (no EPS) but without the blood problems. Perhaps overly simplistically, we now refer to the older chlorpromazine-like drugs as “typical” or first-generation antipyschotics, and the newer clozapine-Zyprexa drugs as “atypical” or second-generation antipsychotics.
The overwhelming majority of new antipsychotic drug prescriptions are written for such atypical drugs as Zyprexa, risperidone (Risperdal), and quetiapine (Seroquel). Many factors have contributed to their marketplace success, not the least of which have been aggressive promotional claims that these drugs not only cause fewer side effects but also are more effective than typical antipsychotics in controlling schizophrenia. These claims are largely based on drug company—financed studies. More objective clinical evidence from government-sponsored tests conducted in the United Kingdom and the United States have yielded conflicting results regarding their relative superiority. The jury remains out.
To varying degrees, the atypical antipsychotics—but, in particular, clozapine and Zyprexa—cause increased weight gain (sometimes very considerable) and potentially serious metabolic effects. These latter problems increase the risk of developing or worsening of existing diabetes, high blood pressure, and increased blood cholesterol levels associated with heart disease. Zyprexa’s manufacturer has long sought to minimize these problems.
The distinction between typical vs. atypical antipsychotics is primarily based on their risk of causing EPS and their relative ability to block dopamine vs. dopamine-plus-serotonin subtypes of receptors in the brain. Beyond these, experts are not of single mind as to whether the claimed benefits and reduced risks are, in fact, different. There is a considerable cost differential between these antipsychotic drugs groups. Far less expensive generic equivalents are available for typical drugs, but only several atypical drugs, such as Clozaril and Zyprexa have generics. Are the differences in cost offset by their clinical benefits?
SEE ALSO Drug Receptors (1905), Neurotransmitters (1920), Chlorpromazine (1952), Clozapine (1989).
A faint, ghostlike figure appears in the distance, as might be imagined by a schizophrenic patient. Visual hallucinations are a symptom of schizophrenia, although they are not as common as auditory hallucinations.