Psychosis and Schizophrenia Assessment and Treatment Introduction

Antipsychotic agents, also called neuroleptic or major tranquilizers, are used primarily to treat schizophrenia. Schizophrenia is characterized primarily by a clear sensory but marked thinking disturbance. Second-generation/ Atypical antipsychotics are widely used due to their broad spectrum of receptor activity since they affect Serotonin, dopamine, and GABA neurotransmitters (de Miranda et al., 2020). Besides, they are better at alleviating negative symptoms and cognitive dysfunction than typical antipsychotics. The purpose of this assignment is to develop a study guide for an antipsychotic agent.

Drug Description

Quetiapine, whose brand name goes by Seroquel, is used in treating schizophrenia. It is FDA-approved for treating schizophrenia, Bipolar disorder, and major depressive disorder (MDD) as an adjunctive treatment (de Miranda et al., 2020).

Non-FDA uses

The non-FDA uses of Seroquel include the treatment of generalized anxiety disorder (GAD), Alcohol Dependence, and Insomnia.

According to Ansara (2020), Seroquel exhibits efficacy in managing treatment-resistant-GAD as an adjunctive agent. In this case, smaller doses than those prescribed for schizophrenia and bipolar disorder are usually needed for symptom improvement.
Seroquel has been found to reduce alcohol consumption in heavy drinkers and has the potential for treatment for alcohol dependence, particularly among heavy drinkers (Vatsalya et al., 2020).
Low doses of quetiapine are usually prescribed for insomnia, although this is a non-FDA use due to potential adverse effects like weight gain and akathisia (Boafo et al., 2020).

Drug classification

Seroquel is an antipsychotic under second-generation antipsychotics.

MOA	Pharmacokinetics	Pharmacodynamics
An antagonist for D2 receptors and serotonin receptors.	Absorption: Bioavailability: 100% Peak plasma time: Immediate release-1.5 hr; extended release-6 hrs	Reduces the hallucinations and delusions associated with schizophrenia by blocking dopamine receptors in the mesolimbic system of the brain.
Acts on dopaminergic D1 and D2 receptors.	Metabolism: Metabolized in the liver by CYP3A4
	Elimination: Excretion: Urine (73%), feces (20%).

Appropriate dosing: 150-750 mg/day (Immediate release); 400-800 mg/day (extended release).

Children <12 years: safety not established.

Children >12 years: Dose range 400-800 mg/day (de Miranda et al., 2020).

Geriatrics: 50-200 mg/day (Immediate); 50 mg/day (Extended)

Pregnant and breastfeeding women: Not recommended.

Route of Administration: Orally.

Considerations for dosing alterations: Elderly and patients predisposed to hypotensive reactions.

Half-life: The time it takes for the concentration of a drug to decrease to half of its initial dose in the body.

Understanding half-life is important because it determines a drug’s excretion rates and steady-state concentrations. After one half-life has passed, half of the starting drug amount is eliminated from the body (Smith et al., 2018).
Seroquel has a half-life of 6 hours for immediate release formulation and 7 hours for extended-release formulation.

Side effects/adverse reaction potentials

Seroquel is associated with various adverse effects, including somnolence fatigue, dry mouth, constipation, increased appetite, weight gain, orthostatic hypertension, and dizziness (de Miranda et al., 2020). Neuroleptic malignant syndrome is a possible adverse effect due to the drug’s D2 receptor blockage.

Contraindications for use including significant drug-to-drug interactions

Currently, no identified FDA contraindications of quetiapine.
It is contraindicated in patients with documented hypersensitivity.
However, quetiapine is associated with an increased risk of death in elderly patients with dementia-related psychosis (Osborne et al., 2020).
Precaution is needed with drugs that prolong QT intervals and patients with prolonged QT intervals.

Contraindications due to drug-to-drug interactions

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