Clozapine and Pimozide Overview

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Questions and Answers

What is the prevalence of tardive dyskinesia in patients on long-term antipsychotics?

20-30%

Which medication can be prescribed as a treatment for tardive dyskinesia according to the provided content?

Valbenazine

Name two risk factors for developing tardive dyskinesia.

Extreme of age and being female.

What is a commonly used medication to alleviate acute dystonia?

Diphenhydramine Signup and view all the answers

What is the onset time for tardive dyskinesia after the withdrawal of oral antipsychotics?

4 weeks. Signup and view all the answers

What should be done if a patient experiences a clozapine-induced tonic-clonic seizure?

Decrease the next clozapine dose and add an antiepileptic. Signup and view all the answers

What is the initial action to take after a clozapine-induced seizure?

Stop clozapine for one day. Signup and view all the answers

After stopping clozapine for one day, what is the recommended approach to resuming treatment?

Resume clozapine at half of the previous dose. Signup and view all the answers

Why is it important to add an antiepileptic when managing clozapine-induced seizures?

To provide additional seizure control and prevent recurrence. Signup and view all the answers

What long-term strategy may assist in managing the risk of seizures in patients on clozapine?

Regular monitoring and dosage adjustments as needed. Signup and view all the answers

Which atypical antipsychotic is known for having a lower risk of extrapyramidal symptoms (EPS) compared to others?

Clozapine Signup and view all the answers

What are the medications associated with dose-related akathisia and parkinsonian symptoms?

Olanzapine and Ziprasidone Signup and view all the answers

Name two atypical antipsychotics that are part of the group least associated with EPS.

Quetiapine and Olanzapine Signup and view all the answers

Which medication is used to treat extrapyramidal symptoms (EPS)?

Benztropine Signup and view all the answers

Identify one antipsychotic known for causing akathisia.

Olanzapine Signup and view all the answers

What is the FDA approval indication for Pimozide?

Pimozide is FDA approved for Tic disorder. Signup and view all the answers

What is the starting dose of Clozapine?

The starting dose of Clozapine is 12.5 mg once or twice daily. Signup and view all the answers

What is the recommended maximum dose of Clozapine?

The maximum dose of Clozapine is 900 mg. Signup and view all the answers

How long does it usually take to achieve the target Clozapine dose of 300 mg?

It can usually be achieved in 2 to 3 weeks. Signup and view all the answers

State one reason why lower doses of Clozapine might be given.

Lower doses are given to elderly patients or those who are medically ill. Signup and view all the answers

What steps should be taken to manage resistant schizophrenia on Clozapine?

Stop substance use, provide psychosocial intervention, and consider augmentation. Signup and view all the answers

What are the risks associated with Clozapine use?

The risks include agranulocytosis, seizures, and myocarditis. Signup and view all the answers

What is the recommended action if a patient stops taking Clozapine for 48 hours?

Restart titration at 12.5 mg after 48 hours of discontinuation. Signup and view all the answers

Why is Clozapine not recommended during breastfeeding?

Clozapine is not recommended during breastfeeding due to potential risks to the infant. Signup and view all the answers

How does smoking affect Clozapine levels?

Smoking decreases Clozapine levels through induction of enzyme 1A2. Signup and view all the answers

What potential adverse effect is associated with Thioridazine?

Severe hypotension Signup and view all the answers

Name a medication mentioned alongside Thioridazine.

Chlorpromazine Signup and view all the answers

How does Thioridazine's risk profile compare to that of Chlorpromazine?

Thioridazine may have a higher risk of severe hypotension compared to Chlorpromazine. Signup and view all the answers

What class of drugs does Thioridazine belong to?

Antipsychotics Signup and view all the answers

What is a critical monitoring consideration when prescribing Thioridazine?

Monitoring for blood pressure changes. Signup and view all the answers

What is the first step in managing akathisia?

Decrease dose Signup and view all the answers

What is the primary reason for akathisia development in a 40-year-old male patient on risperidone 1mg?

Dose of medication Signup and view all the answers

Which antipsychotic injection is associated with post-injection delirium sedation syndrome (PDSS)?

Olanzapine Signup and view all the answers

What is the rate of PDSS occurrence in patients injected with specific antipsychotics?

Less than 10% Signup and view all the answers

Which factor is not associated with an increased risk of QTc prolongation?

Ampicillins Signup and view all the answers

Study Notes

Pimozide and Clozapine

Pimozide is FDA-approved for tic disorders, augmentation in trichotillomania, and delusional disorder, also reducing paranoid ideation in paranoid personality disorder.
Clozapine is used for resistant schizophrenia (25-40% prevalence). Management includes stopping substance abuse, psychosocial interventions, and augmentation strategies.
Clozapine dosage starts at 12.5mg, increasing by 25-50mg daily up to a maximum of 900mg. A minimum effective dose of 150mg is required, with response generally occurring between this range. Plasma levels should be 350-420ng/ml, though UK uses 450mg as a target dose (achievable in 2-3 weeks)

Clozapine Dosage Adjustments

Dosage adjustments are influenced by smoking status & age. Smokers require a higher dose (e.g. 550mg for males, 450mg for females). Non-smokers require a lower dose (e.g., 350mg for males, 250mg for females).
Elderly patients and those with medical illnesses, or who are taking enzyme inhibitors (2D6, 3A4, and 1A2) may require lower doses.

Restarting Clozapine

A table from the Maudsley 13th edition details restarting clozapine:
- Up to 48 hours—restart at previous dose without re-titration.
- 48-72 hours—rapid re-titration as soon as possible. First day: half the previous daily dose in divided doses 12 hours apart, then 75% on day 2, the full dose on day 3.
- 72 hours to 1 week—start re-titration with 12.5-25mg, increasing by 12.5-25mg per day to normal daily doses over 3 days.
- More than 1 week—treat as a new patient, re-titrating to the previous dose within 2-4 weeks, increasing based on patient tolerance.
A new approach is detailed using Maudsley 14th edition that suggests 12.5 mg after discontinuation for 48 hours.
Dosage adjustments are recommended if stopping medication over 12 to 16 weeks or through cross-titration over 6 to 8 weeks.

Additional Monitoring and Drug Interactions

Initial work-up includes physical exams, blood tests (CBC, LFT, urea, electrolytes, lipids, glucose/HbA1c), and ECG, with other tests dependent on clinical need.
Monitoring, especially metabolic syndrome monitoring involves baseline and follow-up (monthly) weight, BMI, waist, plasma glucose, and lipids, and Liver Function Tests.
Interactions exist with agranulocytosis and bone marrow suppression drugs (carbamazepine, phenytoin, etc).
Clozapine interacts with numerous drugs, affecting seizure thresholds and agranulocytosis risks through increasing or decreasing clozapine's concentration levels.

Other Antipsychotics and Side Effects

Various antipsychotics and their side effects are discussed, including risks, monitoring and treatment protocols (such as those related to Clozapine-induced myoclonus or agranulocytosis).
Side effects like seizures, myocarditis, neutropenia, agranulocytosis, akathisia, TD (tardive dyskinesia) are extensively discussed in terms of frequency and potential causes as well as their respective management strategies.
Paliperidone and risperidone dosages and administration information (oral and long-acting formulations) are summarized in tables.
Olanzapine use, including efficacy and comparative data in CATIE, is detailed.
Antipsychotic-induced hyperprolactinemia, its causes, and potential associated symptoms (reproductive dysfunction) are also listed

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Description

This quiz covers key information about Pimozide and Clozapine, including their uses, dosage guidelines, and management strategies for various psychiatric disorders. Participants will also learn how factors like smoking status and age can affect dosage adjustments.