Psychotherapeutic Drugs: Nursing Pharmacology Study Guide

Psychotherapeutic Drugs: Generic and Brand Names

• Antipsychotic or Neuroleptic Drugs
  • Typical antipsychotics
    • chlorpromazine (Thorazine)
    • fluphenazine (Prolixin)
    • haloperidol (Haldol)
    • loxapine (Loxitane)
    • thiothixene (Navane)
  • Atypical antipsychotics
    • clozapine (Clozaril)
    • olanzapine (Zyprexa)
    • quetiapine (Seroquel)
    • risperidone (Risperdal)
• Antimanic Drugs
  • lithium carbonate (Eskalith)
• Central Nervous System Stimulants
  • armodafinil (Nuvigil)
  • atomoxetine (Strattera)
  • dexmethylphenidate (Focalin)
  • dextroamphetamine (Dexedrine)
  • guanfacine (Intuniv)
  • methylphenidate (Ritalin, Concerta)
  • modafinil (Provigil)

Disease Spotlight: Mental Disorders

Mental disorders stem from inherent dysfunction within the brain that drives abnormal thought processes and responses. Earlier thinking blamed environmental factors and life experiences (domestic violence, bullying); other theories point to chemical imbalances in specific brain regions. Diagnosis is based on the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-V-TR), which describes the distinguishing characteristics of each disorder. Psychotherapeutic agents are most commonly indicated for these:

• Schizophrenia. The most common and most disabling psychosis. Hallucinations, paranoia, delusions, speech abnormalities, and affective problems, with a strong genetic association.
• Mania and bipolar illness. Mania is extreme overactivity and excitement tied to bipolar illness, which alternates between depression and hyperactive excitement. It reflects neuronal overcompensation and the failure to re-establish stability.
• Narcolepsy. Daytime sleepiness and sudden loss of wakefulness, linked to a fault in the reticular activating system's (RAS) stimulating effect on the brain.
• Attention-deficit disorders. Mostly school-aged children, marked by inability to concentrate on one activity longer than a few minutes and a state of hyperkinesis.

Antipsychotic (Neuroleptic) Drugs

Antipsychotics are dopamine-receptor blockers for disorders of thought process. They are called neuroleptics for their neurological adverse effects; the older term "major tranquilizers" was dropped because sedation is not the primary action. Two classes: typical and atypical.

Therapeutic Action

The primary action is changing neuron stimulation and response. Typical antipsychotics block dopamine receptors so dopamine cannot stimulate postsynaptic neurons; they also carry anticholinergic, antihistaminic, and alpha-adrenergic blocking effects tied to that dopamine blockade, and they depress the RAS to limit stimulation reaching the brain. Atypical antipsychotics block both dopamine and serotonin receptors, and that dual blockade eases the neurological adverse effects seen with typical agents.

Indications

Typical antipsychotics treat schizophrenia and other psychotic manifestations including hyperactivity, combative behavior, and severe behavioral problems; some are approved for bipolar disorder. Atypical antipsychotics treat severely ill schizophrenia patients unresponsive to standard drugs and reduce recurrent suicidal behavior in schizophrenia and schizoaffective disorder.

Specific agents: chlorpromazine, an older agent, decreases perioperative restlessness and apprehension and also treats intermittent porphyria, tetanus (adjunct), and intractable hiccups, nausea, and vomiting. Haloperidol covers acute psychiatric situations and comes in IV form for patients who need prolonged parenteral therapy but cannot swallow. Prochlorperazine treats severe nausea and vomiting from surgery and chemotherapy. Aripiprazole, a newer atypical, treats schizophrenia, major depressive disorder, and bipolar disorders and comes in IV form for acute agitation. Risperidone is commonly used for irritability and aggression in children and adolescents with autism.

By age group: in children, antipsychotics are often combined with CNS stimulants to control symptoms and behavior, long-term effects are unknown, the pediatric dose usually runs higher than the adult dose, and you monitor closely for adverse effects and developmental progress. In adults, monitor closely (thioridazine and ziprasidone can change the QT interval) and use caution in pregnancy and lactation; stopping the drug can bring symptoms back, so counseling matters. In older adults, reduce doses, do not use these drugs to control behavior in dementia, and watch QT prolongation in patients with coronary disease.

Pharmacokinetics (Typical Antipsychotics)

Here are the characteristic interactions of typical antipsychotics and the body in terms of absorption, distribution, metabolism, and excretion:

Pharmacokinetics (Atypical Antipsychotics)

Here are the characteristic interactions of atypical antipsychotics and the body in terms of absorption, distribution, metabolism, and excretion:

Contraindications and Cautions

Avoid or use caution with diseases worsened by dopamine blockade; CNS depression, circulatory collapse, Parkinson's disease, coronary disease, severe hypotension, bone marrow suppression, and blood dyscrasias. QTc prolongation contraindicates mesoridazine, thioridazine, and ziprasidone (risk of serious cardiac arrhythmias). In dementia, use carries increased risk of cardiovascular events and death; all antipsychotics carry an FDA boxed warning that elderly patients with dementia-related psychosis treated with these drugs have an increased risk of death (FDA quetiapine labeling). Anticholinergic effects worsen glaucoma, peptic ulcer, and urinary or intestinal obstruction. Seizure disorders and thyrotoxicosis lower the seizure threshold. Active alcoholism potentiates CNS depression. Use caution in immunosuppression and cancer (bone marrow suppression, blood dyscrasias) and in pregnancy and lactation. Use caution in children younger than 12 years of age with chicken pox or a CNS infection, who are more likely to develop dystonia that can confuse the diagnosis of Reye's syndrome.

Adverse Effects

CNS: weakness, sedation, tremor, drowsiness, extrapyramidal side effects, pseudoparkinsonism (muscle tremors, cogwheel rigidity, drooling, shuffling gait, slow movements), dystonia (spasm of the tongue, neck, back, and legs), akathisia (continuous restlessness and inability to sit still, foot tapping, hand movements), tardive dyskinesia (lip smacking, tongue darting, chewing movements, slow aimless arm and leg movements), and the potentially irreversible neuroleptic malignant syndrome. CV: hypotension, orthostatic hypotension, cardiac arrhythmias, CHF, pulmonary edema. Respiratory: laryngospasm, dyspnea, bronchospasm. Anticholinergic: dry mouth, nasal congestion, flushing, constipation, urinary retention, impotence, glaucoma, blurred vision, photophobia. Phenothiazines can turn urine pink to reddish-brown, which has no clinical significance.

Interactions

Evening primrose increases symptoms and CNS hyperexcitability. Beta-blockers increase the effects of both drugs. Alcohol increases the risk of CNS depression.

Nursing Considerations

Screen for the cautions and contraindications above and get a baseline (other medications, CNS, skin, respirations, and labs including thyroid, liver, and renal function and CBC). Do not let the patient crush or chew sustained-release capsules, which speeds absorption and risks toxicity. After parenteral doses, keep the patient recumbent for 30 minutes to reduce orthostatic hypotension. Monitor CBC and stop the drug at signs of bone marrow suppression. Monitor blood glucose with long-term use for glucose intolerance. Provide comfort measures (positioning for dyskinesia, sugarless candy and ice chips for dry mouth, voiding before doses for urinary hesitancy) and safety measures (lighting, raised side rails). Evaluate against a decrease in psychotic signs and symptoms, and watch for sedation, extrapyramidal effects, hypotension, and bone marrow suppression.

Antimanic Drugs

Antimanic drugs control the mania of bipolar disorder, thought to come from neuronal overstimulation. Lithium is the drug of choice and the mainstay of treatment.

Therapeutic Action

Lithium alters sodium transport in nerve and muscle cells and inhibits the release of norepinephrine and dopamine, but not serotonin, from stimulated neurons. It also lowers intraneuronal second messengers, selectively modulating the responsiveness of the hyperactive neurons that drive the manic state.

Indications

Manic episodes of bipolar and manic-depressive illness. By age group: lithium has no recommended pediatric dose and is not ordinarily used in children, but if used requires close monitoring of renal, CNS, CV, and endocrine function. In adults, back it with hydration and salt intake and monitor closely; use caution in pregnancy and lactation, and counsel that stopping can bring symptoms back. In older adults, reduce the dose because this group is more susceptible to adverse effects.

Pharmacokinetics

Here are the characteristic interactions of antimanic agents and the body in terms of absorption, distribution, metabolism, and excretion:

Contraindications and Cautions

Allergy to lithium. Significant renal and cardiac disease (worsened by the drug's toxic effects). History of leukemia, metabolic disorders, dehydration, or diuretic use: lithium depletes sodium reabsorption and can cause severe hyponatremia. Protracted diarrhea or excessive sweating can alter sodium levels. Use caution in pregnancy and lactation, and advise women of childbearing age to use birth control while on the drug.

Adverse Effects

Drug effects associated with lithium are directly related to serum levels of the drug.

Interactions

Haloperidol can cause an encephalopathic syndrome (weakness, lethargy, confusion, tremors, extrapyramidal symptoms, leukocytosis, irreversible brain damage). Carbamazepine increases CNS toxicity. Iodide salt increases the risk of hypothyroidism. Thiazide diuretics increase the risk of lithium toxicity. Urine-alkalinizing drugs, antacids, and tromethamine decrease lithium effectiveness. Indomethacin and NSAIDs raise plasma lithium levels. Psyllium blocks lithium absorption.

Nursing Considerations

Screen for the cautions and contraindications above (allergies, renal or CV disease, suicidal or impulsive patients with severe depression, dehydration, sodium depletion) and get a baseline including serum lithium levels, thyroid, liver, and renal function, and CBC. Monitor serum lithium levels daily for toxic levels and adjust the dose. Give with food or milk to reduce GI discomfort. Decrease the dose after acute manic episodes, since lithium tolerance is greatest during the acute episode and falls once it passes. Provide comfort measures (sugarless lozenges, frequent mouth care) and safety measures. Evaluate against decreased frequency and intensity of manic episodes, and watch for CV toxicity, renal toxicity, and GI upset. Lithium has a narrow therapeutic index; FDA labeling notes that levels close to therapeutic can produce toxicity, so serum levels are monitored closely.

Central Nervous System Stimulants

CNS stimulants treat attention-deficit disorders and narcolepsy. They calm hyperkinetic children and help them focus longer, and they redirect and excite arousal stimuli from the RAS. Most are controlled substances, so teach patients to secure them against misuse and diversion.

Therapeutic Action

CNS stimulants act as both cortical and RAS stimulants, likely by increasing catecholamine release from presynaptic neurons, which raises stimulation of postsynaptic neurons. The paradoxical calming effect in hyperkinetic children is thought to come from increased stimulation of an immature RAS, letting the child respond more selectively to incoming stimuli.

Indications

Attention-deficit disorders and narcolepsy. By age group: in children, use extended-release preparations cautiously because they differ markedly in timing and effectiveness, and reassess periodically whether the drug is still needed. In adults, monitor closely and use caution in pregnancy and lactation. In older adults, reduce the dose.

Pharmacokinetics

Here are the characteristic interactions of CNS stimulants and the body in terms of absorption, distribution, metabolism, and excretion:

Contraindications and Cautions

Allergy to CNS stimulants. Marked anxiety, agitation, tension, severe fatigue, and glaucoma can be worsened by CNS stimulation. Cardiac disease and hypertension can be aggravated by the stimulatory effects. History of seizures can be potentiated. History of drug dependence, including alcoholism, since these drugs can cause physical and psychological dependence. Use caution in pregnancy and lactation.

Adverse Effects

CNS: nervousness, insomnia, dizziness, headache, blurred vision, difficulty with accommodation. CV: hypertension, arrhythmias, angina. GI: anorexia, nausea, weight loss. Skin rashes are common. Physical and psychological dependence.

Interactions

MAOIs increase the risk of adverse effects and toxicity. Guanethidine loses antihypertensive effect. TCAs and phenytoin show increased drug levels.

Nursing Considerations

Screen for the cautions and contraindications above (allergies, seizure disorder, anxiety, tension, fatigue) and get a baseline including CNS, skin, respirations, and liver and renal function and CBC. Interrupt the drug periodically in children to see whether symptoms recur and therapy should continue. Dispense the least amount of drug possible to limit overdose and abuse risk. Give the drug before 6 PM to reduce insomnia. Monitor weight, CBC, and ECG for early detection of adverse effects. Provide safety measures. Evaluate against a decrease in behavioral symptoms and daytime sleep, and watch for CNS stimulation, CV effects, rash, and dependence.

Frequently Asked Questions

Do psychotherapeutic drugs cure mental illness? No. They do not cure psychosis or other disorders; they make thought processes and behavior manageable enough that a person can perform activities of daily living and function more acceptably.

What is the difference between typical and atypical antipsychotics? Typical antipsychotics block dopamine receptors and carry more neurological side effects. Atypical antipsychotics block both dopamine and serotonin receptors, and that dual action eases many of the extrapyramidal effects seen with typical agents.

Why are antipsychotics not used to manage behavior in older adults with dementia? All antipsychotics carry an FDA boxed warning that elderly patients with dementia-related psychosis have an increased risk of death when treated with these drugs, mostly from cardiovascular or infectious causes.

Why does a patient on lithium need frequent blood tests? Lithium has a narrow therapeutic index, so toxic levels sit close to therapeutic ones. Serum levels are monitored to keep the patient in range and catch early toxicity, which begins to appear above 1.5 mEq/L.

What are extrapyramidal symptoms? Movement-related side effects of antipsychotics, including pseudoparkinsonism, dystonia, akathisia, and tardive dyskinesia. Neuroleptic malignant syndrome is a rare, potentially irreversible emergency.

When should CNS stimulants for ADHD be given? Give the dose before 6 PM to reduce insomnia, dispense the smallest practical amount because most are controlled substances, and periodically interrupt therapy in children to see whether symptoms recur.