There is a selective nature that this drug exhibits for the mesolimbic region. Not only that but there is also a significant affinity that it has on a number of receptors, including; dopaminergic, serotonergic, and muscarinic receptors. An effect of an alpha blockade may lead to orthostatic hypotension and sexual dysfunction. A blockage of H1 causes sedation.

Pharmacology

Clozapine is absorbed after oral administration, however, it can undergo extensive metabolism. With bioavailability from 12-81%, the administration of clozapine can be seen to have an effect with or without food. The peak time of plasma concentration is approximately 3-4 hours. As it is metabolized in the liver, clozapine may exceed concentrations of parent compounds. There is activity at the D2 and 5-HT2 receptors. 

Pharmacokinetics

1. Baseline white blood cell count has been obtained
2. Patient registered with the Clozaril National Registry
3. 12.5 mg of clozapine on the first day and then increased by 12.5mg per day for three days 2 times per day. Then the dose should be 25mg per day until the target 300mg per day is reached. It should be administered at night to minimize adverse effects. 
- Elderly patient dosing should be connservative with initiation at half the regular dose. 
- Most useful in nonresponse to therapeutic dosage
- Clozapine available in 25 and 100 mg scored tablets.

Dosing Guidelines

Although fatalities have occurred following an overdose, it is generally at doses of >2500mg. Patients have survived an excess of 4 grams. 
Signs and symptoms: 
1. Drowsiness
2. Hypersalivation
3. Delirium
4. Tachycardia
5. Hypotension
6. Respiratory depression/failure

Toxicology

Clozapine the conventional antipsychotic loxapine was the first atypical drug to become available widely in the US.

University of South Florida

The classic definition: A compound that has clinical antipsychotic efficacy while producing minimal catalepsy. 
Now: An atypical agent is now seen as an agent that 

1. decreased propensity to produce catalepsy or other movement disorders, 

2. does not elevate prolactin concentrations, 

3. significantly reduced positive and negative symptoms of schizophrenia.

Atypical Antipsychotics - What is an atypical Antipsychotic?

Those with pre-existing psychiatric condition(s) are at greater risk of binge eating disorder. For example, high-risk groups such as war veterans display a greater number of eating disorder symptoms and have higher rates of BED than the general population. Furthermore, schizophrenia and schizoaffective disorder patients similarly have higher-than-normal rates of BED, and alarmingly high rates (18.7%) of subthreshold BED, often as a result of prescribed atypical antipsychotics, specifically clozapine and olanzapine.

Comorbid Psychiatric Conditions and Binge Eating Disorder Risk

Markowitz, J. S., Brown, C. S., &amp; Moore, T. R. (1999). Atypical antipsychotics part I: Pharmacology, pharmacokinetics, and efficacy. Annals of Pharmacotherapy, 33(1), 73–85. https://doi.org/10.1345/aph.17215 

Atypical Antipsychotics; Part 1: Pharmacology, Pharmacokinetics, and Efficacy

Table 1

Table 2

Clozapine

Schizophrenia is a severe psychological disorder that leads to a profound breakdown in an individual's ability to function, often necessitating hospitalization. It is characterized by significant disruptions in thought, perception, emotion, and behavior, including symptoms like hallucinations, delusions, incoherent thinking, bizarre actions, flat emotions, and a lack of motivation for basic activities. It is important to distinguish schizophrenia from dissociative identity disorder ('split personality'), as the term 'schizophrenia' refers to a 'splitting of psychic functions,' not a divided personality.

Schizophrenia

An uninterrupted illness featuring at some time a major depressive episode, manic episode, or mixed episode concurrently with characteristic symptoms of schizophrenia (e.g., delusions, hallucinations, disorganized speech, catatonic behavior) and, in the same period, delusions or hallucinations for at least 2 weeks in the absence of prominent mood symptoms. DSM–5 identifies the mood episodes only as either major depressive or manic and emphasizes that mood disturbances must be present for a majority of the time.

Schizoaffective Disorder

These are a class of antipsychotic drugs that have a high affinity for other types of receptors and not dopamine receptors. They are also known as 2nd Generation Antipsychotics. They can be prescribed for Schizophrenia and other types of severe thought disorders. They can target dopamine and serotonin receptors to treat schizophrenia's negative symptoms, such as withdrawal and apathy; newer drugs may treat both positive and negative symptoms.

Atypical Antipsychotics include: 
- Aripiprazole (Abilify)

- Clozapine (Clozaril)

- Olanzapine (Zyprexa)

- Quetiapine (Seroquel)

- Risperidone (Risperdal)

- Ziprasidone (Geodon)

Learn Before

Related

Learn After