NURS 6630 Study Guide for Medication Treatment Schizophrenia Spectrum and Other Psychosis Disorders

NURS 6630 Study Guide for Medication Treatment Schizophrenia Spectrum and Other Psychosis Disorders Schizophrenia is characterized mainly by a clear sensory but a marked thinking disturbance. The psychotic disorder is highly linked with abnormalities of amine neurotransmitter function, especially dopamine. Antipsychotic medications, also called neuroleptic or major tranquilizers, are the first-line drug therapy for schizophrenia. They target the positive symptoms of schizophrenia, like hallucinations, delusions, and disorganized behavior. Antipsychotics act by controlling neurotransmitter dopamine and serotonin levels in the brain. They are classified into two major groups: Typical and Atypical. The antipsychotic effects of Typical antipsychotics owe their competitive blockage to dopamine receptors. Atypicals have fewer extrapyramidal adverse effects than the typical and block both serotonin and dopamine receptors. The purpose of this assignment is to develop a study guide for Risperidone. Drug Description Risperidone is also called Risperdal. It is an Atypical neuroleptic medication. The FDA approves it for use in the USA in the treatment of: Schizophrenia in adults and children aged above 13 years. Bipolar I acute manic or mixed episodes as monotherapy in adults and children above 10 years (Álamo, 2022). Bipolar I acute manic or mixed episodes adjunctive with lithium or valproate in adults. Autism-associated irritability in children above five years. Off-label uses include: Borderline personality disorder Delusional disorder Delirium Depression Brain injury Pedophilia PTSD Bipolar disorder Conduct disorder Lesch-Nyhan Tourette Syndrome Stuttering, movement disorders Developmental disorders The medication mechanism of action Risperidone has a high affinity for serotonin type 2 (5-HT2) receptors. It binds to dopamine D2 receptors with 20 times lower affinity than that for 5-HT2 receptors (Zhao et al., 2022). It antagonizes alpha1-adrenergic, alpha2-adrenergic, and histaminergic receptors. Risperidone has a moderate affinity for serotonin type 1 receptors. Has a weak affinity for dopamine D1 receptors. No affinity for muscarinic, beta1-adrenergic, and beta2-adrenergic receptors (Zhao et al., 2022). Pharmacokinetics Pharmacodynamics Risperidone decreases dopamine neurotransmission for the five classes of dopamine receptors (D1 to D5). It reduces the hallucinations and delusions associated with schizophrenia by blocking dopamine receptors in the brain’s mesolimbic system (Zhao et al., 2022). Appropriate dosing and administration route, Oral: Initial dose at 2 mg/day; Recommended target dosage of 2-8 mg/day OD or BD. The oral dose may be increased by 1-2 mg/day at intervals ≥24 hr. Intramuscular: 12.5-50 mg into the deltoid or gluteal muscle every 2 weeks; The dose should not be adjusted more often than every 4 weeks. Subcutaneous: 90 mg or 120 mg SC once monthly. Considerations For Dosing Alterations Renal Impairment: If Creatine clearance is below 30, PO Risperidone should be initiated at 0.5 mg BD. It can be increased by up to 0.5 mg BD to a max of 1.5 mg BD. Considerations of use and dosing in specific specialty populations Geriatrics: Lower initial doses are recommended and should be adjusted more gradually. PO initial dose at 0.5 mg q12hr; IM: 12.5-25 mg (Álamo, 2022). Pediatrics >13 years: Initiated at lower doses of 0.5 mg/day PO in the morning or evening. Half-life: This is the time taken for the plasma or blood level of a drug to fall by half. Half-life is determined by drug distribution, metabolism, and excretion. Half-life is important because drugs that have a short half-life stay in the body for a shorter period and thus have a shorter duration of action (Andrade, 2022). Drugs with a short half-life thus need to be administered more frequently. Drugs with a long half-life stay longer in the body and thus have a longer duration of action (Andrade, 2022). These drugs can conveniently be dosed once a day or less frequently. Extensive Risperidone metabolizers have a half-life of 3 hrs (parent and metabolite combined). Poor metabolizers have a half-life of 20 hrs (parent and metabolite combined). Side effects/adverse reaction potentials The most significant side effects are Weight gain, metabolic changes, and sedation. It is associated with extrapyramidal symptoms (EPS): Acute dystonia, tardive dyskinesia, akathisia, and parkinsonian features (Hodkinson et al., 2021). Neuroleptic malignant syndrome (NMS) is a serious side effect of Risperidone. Other side effects: Somnolence, Insomnia, Agitation, Anxiety, Headache, Rhinitis, Fatigue, Increased appetite, Vomiting, Drooling, and Urinary incontinence (Hodkinson et al., 2021). Contraindications for use and drug-to-drug interactions Risperidone is contraindicated in patients with known allergy/hypersensitivity to Risperidone or paliperidone (Hodkinson et al., 2021). Contraindicated in dementia-related psychosis due to increased