Psychopharmacology Overview

Psychopharmacology

Psychopharmacology is the study of drugs' chemistry, actions, and clinical use in treating mental disorders.
The brain consists of neurons, the basic units of the nervous system, responsible for receiving and transmitting information.
Neurons are composed of dendrites, cell bodies, axons, and axon terminal buttons.
Dendrites receive information, transmitted to the cell body; axons send information to other neurons' dendrites.
The synaptic gap is the space between neurons where an electrical signal transforms to a chemical signal.
Neurotransmitters are chemical messengers synthesized from precursors (e.g., amino acids) and stored in vesicles in the presynaptic terminals.
Neurotransmitters are classified as excitatory or inhibitory, influencing the signal transmission between neurons.
Key neurotransmitters include dopamine, GABA, norepinephrine, serotonin, and acetylcholine, each associated with specific mental health conditions.
Receptors are proteins that respond to neurotransmitters.
Receptor agonists activate receptors; antagonists block them, influencing the receptor's function.
Toxicity is the drug concentration level becoming harmful or poisonous.
The therapeutic index shows the ratio of the maximum non-toxic dose to the minimum effective dose.
Target symptoms are the specific symptoms medication aims to alter.
Half-life is the time required to metabolize or eliminate half the drug quantity.
Polypharmacy involves using multiple psychotropics to treat different conditions.
Efficacy is the drug's ability to achieve the desired response.
Potency is the amount of drug needed to achieve the therapeutic effect.
Pharmacodynamics is the drug's biological and physiological effects on tissues via interactions with receptors.
Pharmacokinetics describes the body's impact on the drug, encompassing absorption, distribution, metabolism, and excretion.

Antipsychotic Medications

Antipsychotics are also known as major tranquilizers, neuroleptics, or dopamine receptor antagonists.
Antipsychotics help by reducing dopamine activity.
Antipsychotic medications primarily work by blocking dopamine receptors.
Discovered accidentally around 1950.
Chlorpromazine is the first antipsychotic drug.
Indications include schizophrenia, acute mania, resistant bipolar disorder, dementia with psychotic symptoms, severe obsessive-compulsive neurosis, and aggressive/sociopathic personalities. Non-psychiatric uses include nausea, vomiting, and intractable hiccups.
Contraindications such as cardiovascular diseases (especially MI), hypotension/hypertension, epilepsy, liver disease, Jaundice, Parkinson's disease, CNS depressants, and drug hypersensitivity must be considered.

Classification of Antipsychotics

First classification is based on the chemical class of the drug.
Phenothiazines (e.g., chlorpromazine, chlorpropmide, thioridazine, trifluoperazine, fluphenazine, perphenazine) are often categorized further by the chemical structure of their side chain.
Butyrophenones (e.g., haloperidol)
Miscellaneous antipsychotics (e.g., thiothixene, clozapine, respirdone)
Second classification is based on potency.
High-potency drugs have a lower dose, lower sedation, and higher EPSES (extrapyramidal side effects).
Moderate-potency drugs have a moderate dose, moderate sedation, and moderate EPSES.
Low-potency drugs have a high dose, high sedation, and low EPSES.
Atypical antipsychotics (second generation) differ from typical antipsychotics in reducing EPSES, increased effectiveness in treating negative or cognitive symptoms, and efficacy for patients with non-response to typical agents.
Novel antipsychotics (third generation) are dopamine system stabilizers to balance and modulate dopamine activity.

Side Effects and Nursing Interventions

Side effects, including extrapyramidal side effects (e.g., dystonia, akathisia, parkinsonism, tardive dyskinesia), and anticholinergic effects (e.g., constipation, dry mouth, blurred vision, urinary hesitation) are crucial to understand and address.
Side effects such as NMS (neuroleptic malignant syndrome) and agranulocytosis can be life-threatening.
Education of patients and families about potential side effects and appropriate nursing interventions, as well as the importance of monitoring, are critical to patient safety and management.

Anti-Parkinsonian Drugs

Indications include extrapyramidal side effects (EPSES) caused by antipsychotic drugs, Parkinson's disease, and tremor associated with certain other medications such as lithium or antidepressants.
Contraindications include glaucoma, GI obstruction, prostatic hypertrophy, urinary problems, or cardiac or pregnancy related issues.
Classification includes anticholinergic drugs, dopaminergic drugs, beta-blockers, and others.
Mechanism of action involves altering the balance between dopamine and acetylcholine in the brain.

Forms of Antipsychotics

Oral and injectable forms exist.
Injectable forms (depot) are long-acting oil-based medications for slow drug release over weeks.
Typical and atypical agents have specific depot formulas and duration.
Instructions on how to administer both types of injectables are critical.

Drug Interactions

Common interactions include those with other sedating medications, alcohol, antacids, and other drugs.
Patients and/or families need to be aware of the effects of drug interactions so that they, or their physicians, can make decisions about the safest approach.

Teaching Patients and Family

Education of patients and their families about potential medication side effects is necessary for patient safety and management.
Importance of monitoring signs (e.g., fever, sore throat, bleeding) is crucial and should be made clear to patients/families.
Patient instruction to alert healthcare providers of potential side effects is critical for interventions to prevent long-term complications.
Educating patients about managing potential side effects.

Nursing Actions

Nurses should be proactive in monitoring patients' responses to medication and adjusting care as needed.
Anticholinergic side effects are often the first thing nurses notice and should be monitored actively.
It is imperative that nurses educate patients and their families on how to manage side effects.

Teaching Patients

Patients shouldn't abruptly stop taking medications.
Importance of fluid intake and other interventions to prevent side effects.
Reporting any changes to doctors for proper assessments of patient status, so that the right decisions can be made about medication administration and frequency.