Antipsychotics: Nursing pharmacology

Antipsychotics are medications mainly used to treat schizophrenia and other psychotic disorders, such as psychosis, acute mania, delirium, bipolar disorders, and obsessive-compulsive disorders.

Antipsychotics are most often administered orally, but some can also be sublingual or transdermal or injected intramuscularly, intravenously, or subcutaneously.

Once administered, they travel to the brain and block dopamine D2 receptors in the mesolimbic pathway, thereby helping alleviate some psychotic symptoms.

Now there are 2 main groups of antipsychotics, the 1st generation or typical antipsychotics, and the 2nd generation or atypical antipsychotics.

Typical antipsychotics can be further classified as high potency or low potency medications. High potency antipsychotics include medications such as haloperidol, trifluoperazine, and fluphenazine.

These medications have a high affinity for dopamine receptors, meaning they require lower doses to achieve their therapeutic effect.

On the flip side, low potency antipsychotics include medications such as thioridazine and chlorpromazine. These medications have less affinity for dopamine receptors, therefore, they require larger doses to achieve the same therapeutic effect as high potency antipsychotics.

On the other hand, 2nd generation or atypical antipsychotics include medications such as clozapine, olanzapine, quetiapine, risperidone, and ziprazodone.

In addition to blocking dopamine D2 receptors, atypical antipsychotics also work by blocking serotonin 5HT2A receptors in the mesocortical pathway.

Another atypical antipsychotic is aceapine, which is administered sublingually or transdermally to prevent clients from cheeking their medication.

That's when a client pretends to swallow their medication, but instead keeps it hidden between the teeth and the cheek. Now, antipsychotics are not selective to the dopamine receptors in the mesolimbic pathway, meaning that they can also block dopamine receptors in other parts of the brain.

In addition, dopamine normally inhibits prolactin release, so by blocking dopamine receptors, antipsychotics subsequently increase the secretion of prolactin, causing galactorrhea or a milk-like nipple discharge.

On the flip side, the blockade of dopamine receptors in the nirostriatal pathway results in extrapyramidal symptoms, which usually involve abnormal movements like dystonia, which can occur within a few hours to days of treatment and includes muscle spasms of the tongue, face, neck, and back.

This side effect is also associated with oculargyric crisis, which is a spasm of the extraocular muscles, causing an upward and outward position of the eyes.

After a few days to a month, a client can develop akathisia characterized by restlessness and an urge to move the limbs, as well as pseudo-Parkinsonism, characterized by muscle rigidity, usually in the facial muscles.

And symptoms such as bradykinesia or slow movements and tremors. Finally, clients may develop tardive dyskinesia after several months to even years characterized by constant involuntary rhythmic movements.

This usually affects the perioral muscles, causing the person to repeatedly smack or purse their lips. Unlike the rest of the extrapyramidal symptoms, which usually disappear once the medication is stopped, tardive dyskinesia can be irreversible, so it's important to discontinue the medication at the first sign of tardive dyskinesia.

Now, the most dangerous extrapyramidal side effect is neuroleptic malignant syndrome, or NMS for short, which typically starts days to weeks after starting the medications.

It's characterized by confusion, muscle rigidity, agitation, hyperthermia, seizures, and even coma. Finally, it's important to note that typical antipsychotics are more likely to cause extrapyramidal side effects compared to atypical antipsychotics.

Now, besides dopamine receptors, antipsychotics can also block other receptors. Other side effects caused by blockade of muscarinic receptors include anticholinergic side effects such as dry mouth, blurred vision, urinary retention, and constipation.

On the other hand, blockade of alpha one adrenergic receptors may cause orthostatic hypotension. Blockade of histamine receptors may result in sedation.

Additionally, atypical antipsychotics can cause metabolic syndrome, which is associated with weight gain, diabetes, dyslipidemia, and increased cardiovascular risk.

Finally, antipsychotics are linked to prolongation of the QT interval, as well as increased risk of death in older adults with dementia-related psychosis.

Contraindications to antipsychotics may include QT prolongation, central nervous system depression, and clients who take them should avoid drinking alcohol.

Finally, it's important to keep in mind that clozapine has a boxed warning for severe neutropenia, seizures, fatal myocarditis, bradycardia, and cardiac arrest.

Now, before administering an antipsychotic medication, be sure your client understands how the medication will help reduce symptoms such as delusions, paranoia, or hallucinations, and let them know it may require several weeks for the medication to take effect.

Then complete a baseline assessment, including mental and behavioral status, level of consciousness, weight, and vital signs.

Next, check your client's latest laboratory report, including CBC, electrolytes, glucose, lipid profile, hepatic and renal function, as well as cardiovascular function.

Lastly, check their current list of medications and confirm that there are no other medications that can interact with the antipsychotic medication and increase the risk of serotonin syndrome or QT prolongation.

After administration, continue to monitor your client's vital signs, changes in mental status, and labs, and report any assessment findings that indicate the development of side effects to the healthcare provider.

Let your client know that sedation is a common side effect, which usually decreases after a few weeks. Remind them that until they adjust to the effects of the medication, they should avoid any type of potentially hazardous activity, such as driving.

Explain that taking their medication in the evening can be helpful in lessening the impact of sedation on their daily activities.

Lastly, advise your client to avoid drinking alcohol or taking certain antihistamines as these may increase sedation. Next, conduct an orthostatic vital sign measurement and note if there is a decrease of greater than or equal to 20 millimeters of mercury systolic or greater than or equal to 10 millimeters of mercury in diastolic BP after 3 minutes of standing, which would indicate orthostatic hypotension.

To decrease risk of falls, teach your client to make position changes slowly. Also, inform your client about the possibility of dry mouth, urinary retention, and constipation.

To minimize these side effects, encourage the use of sugar-free hard candy or chewing gum and frequent drinks of water. Also, remind your client about the importance of good oral hygiene and encourage increased dietary fibers, fluids, and physical activity.

Now, when caring for your client, be sure to monitor closely for serious side effects, such as extrapyramidal symptoms like acute dystonia, tardive dyskinesia, pseudo-Parkinsonism, and neuroleptic malignant syndrome.

If your assessments indicate any of these problems are developing, inform the healthcare provider right away. Should neuroleptic malignant syndrome occur, be prepared to hold the antipsychotic medication, institute supportive measures such as IV hydration and cooling blankets, and administer pharmacological therapeutics like the benzodiazepine lorazepam, the skeletal muscle relaxant dantrolene, or the dopamine agonist bromocriptine as ordered.

When teaching your client and family members about antipsychotic therapy, emphasize the importance of recognizing concerning signs and symptoms such as abnormal movements, restlessness, muscle rigidity, slow movements, tremors, or constant involuntary rhythmic movements such as lip smacking or pursing their lips, and to report occurrence of these promptly to their healthcare provider.

Finally, because some antipsychotics can increase the risk of hyperglycemia, hyperlipidemia, and a granulocytosis, teach your client to recognize and report signs and symptoms of hyperglycemia like polyuria, polydipsia, and polyphagia.

Advise your client that regular monitoring of their lipid profile and CBC will be needed. Stress the importance of avoiding infection.

And remind them to report flu-like symptoms or other signs of infection, such as a sore throat or fever right away. All right, as a quick recap, antipsychotics are medications mainly used to treat schizophrenia and other psychotic disorders.

Once administered, they travel to the brain and block dopamine D2 receptors in the mesolimbic pathway, thereby helping alleviate some psychotic symptoms.

Clients should be monitored closely and advised about extrapyramidal symptoms and other potential side effects, including orthostatic hypotension.

Anticholinergic effects, sedation, and the development of metabolic disturbances such as hyperglycemia and hyperlipidemia.