Conventional Antipsychotics

Conventional antipsychotics are the neuroleptic medications which were initially used to treat schizophrenia for many years, dating as far back as 1952 when Thorazine made its debut in the United States. This group of medications is also often referred to as “first generation antipsychotics”, “typical antipsychotics”, and “major tranquilizers”.

The FDA lists the following medications for this group 1:

  • Haldol (haloperidol)
  • Moban (molindone)
  • Trilafon (perphenazine)
  • Thorazine (chlorpromazine)
  • Mellaril (thioridazine)
  • Navane (thiothixene)
  • Prolixin (fluphenazine)
  • Stelazine (trifluoperazine)
  • Orap (pimozide)
  • Loxitane (loxapine)
  • Compazine (prochlorperazine)

While a few of these drugs have been discontinued for use, many of them, such as haldol, are still used today. Although many newer antipsychotics (“atypical antipsychotics”, “second generation antipsychotics” and even “third generation antipsychotics”) have been introduced and approved for the treatment of schizophrenia, there is still much debate as to which medications are better overall. However, several recent studies are showing that these older antipsychotics are often equally effective as the newer ones.

The CATIE study (The Clinical Antipsychotic Trials of Intervention Effectiveness), a large and lengthy study conducted by the NIMH starting back in 2000 2 was conducted partly to compare several atypical antipsychotics in the treatment of schizophrenia with each other, and also with perphenazine (Trilafon), one of the conventional antipsychotics. The first phase of the study did not show any significant benefit of the atypical antipsychotics over perphenazine.

A 2004 study 3 also failed to show any significant benefits of olanzapine (Zyprexa) over Haldol, in terms of how it affected the neurocognitive functioning of patients who were experiencing their first psychotic break.

Also, a 2008 study comparing molindone (Moban) with newer antipsychotics also shows that it is equally effective in treating schizoaffective disorder as well as early-onset (childhood) schizophrenia 4.

One of the reasons studies like these are important is because the newer medications are extremely expensive compared to the typical antipsychotics. High costs make the new drugs unobtainable for many people with schizophrenia, even if they have health insurance to cover part of the cost.

What typical antipsychotics are used to treat

The typical antipsychotics were primarily approved to treat schizophrenia. They are effective in reducing and / or alleviating the hallucinations, delusions, and thinking problems which are typical symptoms of schizophrenia. Because they are very sedating, they also help decrease symptoms of agitation and anxiety which are also often present.

In more recent years, many drugs in this category have been approved to treat (alone or in combination with other medications) a variety of other disorders. These include Tourette’s Syndrome, acute manic episodes in bipolar individuals, severe cases of nausea and vomiting, extreme childhood behavioral disorders, psychotic depression, and agitation.

How they work

The exact process by which these traditional neuroleptics work in the brain are not completely understood even today. That being said, it is known that they block the receptors for dopamine, which is a neurotransmitter, in the brain. Dopamine imbalance is believed to play a role in the development of psychotic symptoms. Each of the drugs in this group work slightly differently in the brain with regards to dopamine.

The conventional antipsychotics are usually quite effective when it comes to treating hallucinations and delusions. Unfortunately, they don’t really help other symptoms, like the emotional withdrawal, often seen in schizophrenic individuals.

How they’re administered

For acute symptoms, these medications are typically given as an injection. Depending on the medication, most are available in tablet, capsule and oral liquid forms.

Precautions

While there are some minor differences in terms of precautions with the various neuroleptics, some are fairly general. If you are considering taking one of these medications, be sure to inform your doctor if you are taking other medications or have any known drug allergies. Also, be sure to let your doctor know if you or a family member has (or have had) problems urinating, glaucoma, Parkinson’s disease, heart disease, any kind of cardiovascular or lung disease, thyroid problems, epilepsy or any history of seizures, or liver, prostrate or kidney problems. Also, if you are pregnant or nursing, or considering becoming pregnant, be sure to tell your doctor.

Potential side effects

Conventional antipsychotics come with a lot of potential side effects, which is one of the reasons many schizophrenics discontinue the medication after a period of time. One of the most troublesome (and often permanent) side effects associated with these older neuroleptics is tardive dyskinesia (TD). TD symptoms involve involuntary, random and uncontrollable movements, such as lip smacking, odd tongue or jaw movements, blinking, grimacing, and movements involving the limbs, fingers, toes, upper body or hips.

A very serious and potentially fatal possible side effect is neuroleptic malignant syndrome (NMS). Symptoms of NMS include muscle stiffness, changes in one’s mental state, fluctuations in blood pressure or heartbeat, sudden renal failure, tremors, difficulty breathing, dehydration, rapid heartbeat, and extremely high temperature.

A 2009 study suggests a link between sexual dysfunction 5 and the use of these older antipsychotics.

Some mild, but fairly common, side effects include drowsiness, constipation, decreased appetite, nausea and vomiting, blurred vision, tremors, muscle stiffness, and decrease in blood pressure. There are also many other, more serious potential side effects associated with these medications not listed here. Consult with your doctor regarding these.

written by Dr. Cheryl Lane, PsyD

References

  1. Information for Healthcare Professionals: Conventional Antipsychotics
  2. Questions and Answers About the NIMH Clinical Antipsychotic Trials of Intervention Effectiveness Study (CATIE) — Phase 1 Results
  3. Comparative Effect of Atypical and Conventional Antipsychotic Drugs on Neurocognition in First-Episode Psychosis: A Randomized, Double-Blind Trial of Olanzapine Versus Low Doses of Haloperidol
  4. "Double-Blind Comparison of First- and Second-Generation Antipsychotics in Early-Onset Schizophrenia and Schizo-affective Disorder: Findings From the Treatment of Early-Onset Schizophrenia Spectrum Disorders (TEOSS) Study," American Journal of Psychiatry, Sept 15, 2008

schizophrenia