Extrapyramidal effects

AMANTADINE The nurse administers this drug for the prevention or treatment of respiratory tract illness caused by influenza A virus. Some patients are prescribed this drug to manage extrapyramidal effects caused by drugp used to treat Parkinsonism (See Chaps. 29 and 32). The nurse should protect the capsules from moisture to prevent deterioration. When the drug is administered for symptoms of influenza, it is important to start therapy within 24 to 48 hours after symptoms begin. 

Among the most significant adverse reactions associated with the antipsychotic dm are the extrapyramidal effects. The term extrapyramidal effects refers to a group of adverse reactions occurring on the extrapyramidal portion of the nervous system as a result of antipsychotic drains. This part of the nervous system affects body posture and promotes smooth and uninterrupted movement of various muscle groups. Antipsychotics disturb the function of the extrapyramidal portion of the nervous system, causing abnormal muscle movement. Extrapyramidal effects include Parkinson-like symptoms (see Chap. 29), akathisia, and dystonia (see Display 32-1). 

Extrapyramidal effects usually diminish with a reduction in the dosage of the antipsychotic drug. The primary health care provider may also prescribe an antiparkinsonism drug, such as benztropine (see Chap. 29) to reduce the incidence of Parkinson-like symptoms. 

Q Impaired Verbal Communication related to drug-induced extrapyramidal effects (eg, dystonia)... 

When administering the antipsychotic drugs, the nurse observes the patient for extrapyramidal effects , which include muscular spasms of the face and neck, the inability to steep or s t still, tremors rigidity, or involuntary rhythmic movements The nurse notifiesthe primary health care provider of the occurrence of these symptoms because they may indicate a need for dosage adjustment. 

Asa nurse on the psychiatric unit, you are assigned to discuss extrapyramidal effects at a team conference. Discuss how you would present and explain this topic. Describe the points you would stress. 

Antimuscarinic drugs such as atropine have been used to modest effect in the treatment of PD for more than a century attenuating tremor and rigidity but with little effect on akinesia. Currently benzhexol and benztropine are sometimes added to levodopa therapy but peripheral effects such as dry mouth, blurred vision and constipation are unpleasant. They are also often used to counteract neuroleptic-induced extrapyramidal effects. 

Chlorpromazine had been shown to produce a tranquil state in animals and since it had a similar effect in humans it became known as a major tranquiliser but the term is rarely used today. Sometimes the drugs used to treat schizophrenia are called anti-psychotics but more commonly neuroleptics. Leptic means to activate (take hold of) and in animals these compounds produce a state of maintained motor tone known as catalepsy. This is an extrapyramidal effect and in schizophrenics the neuroleptics can cause a number of extrapyramidal side-effects (EPSs) including Parkinsonism. The new term neuroleptic is unsatisfactory as a description of clinically useful drugs. It really describes a condition (catalepsy) seen in animals and is more indicative of a compound s ability to produce EPSs than to treat schizophrenia. Antipsychotic is more descriptive but could imply a more general efficacy in psychoses than is the case. It would seem more appropriate to call a drug that is used to treat schizophrenia an antischizophrenic just as we use the terms antidepressant or antiepileptic irrespective of how the drug works. Despite such personal reservations, the term neuroleptic will be used in this text. 

Most common Sedation, hypotension, tachycardia Less common Extrapyramidal effects, dizziness, increase in blood pressure, chills, hallucinations... 

Most common Sedation, restlessness, diarrhea (metoclopramide), agitation, central nervous system depression Less common Extrapyramidal effects (more frequent with higher doses), hypotension, neuroleptic syndrome, supraventricular tachycardia (with intravenous administration)... 

Typical antipsychotics may also be associated with a small increased risk of death, as well as more severe extrapyramidal effects and hypotension. 

The high potency antipsychotic haloperidol (Haldol) provides the same calming effects with minimal anticholinergic effects. Although haloperidol is very effective, dementia patients are quite sensitive to its extrapyramidal effects. These include stiffness, shuffling gait, a mask-like facial appearance, and involuntary movements. To minimize these effects, haloperidol is used in very low doses (0.5-1.0mg) when treating those with dementia. 

The side effects of conventional antipsychotics are of even greater concern when treating chronic psychosis in a patient with dementia. With sustained administration of a typical antipsychotic, these patients will be highly vulnerable to the extrapyramidal effects of the medication, which can increase the risk for falls. Thus, atypical antipsychotics have also been rapidly accepted as first-line agents when treating... 

Hyponatremia Nephrolythiasis Extrapyramidal effects Corneal opacity... 

Most antipsychotics and especially the piperazines and the butyrophenones can cause extrapyra-midal symptoms. Blockade of dopamine receptors mainly in the corpus striatum is held responsible for these extrapyramidal effects. They may become manifest as a variety of clinical symptoms and it should be noted that within 24 8 hours after the beginning of treatment acute dystonic reactions like torticollis, facial grimacing and opisthotonos may occur. Parkinsonism-like symptoms such as bradyki-nesia, rigidity and tremor occur after weeks or months of therapy and are more common in the elderly. Motor restlessness, i.e. akathisia, also mostly occurs not before weeks or months after starting therapy. The tendency of an antipsychotic agent to produce extrapyramidal symptoms appears to be inversely related to its ability to block cholinergic receptors. 

Chlorpromazine is the best known representative of the aliphatic phenothiazines. Although it is considered to be a low potency agent it is still frequently used. It is one of the most sedative antipsychotic agents and is therefore very effective in the treatment of agitated and violent patients. Extrapyramidal effects are seen with a rather low incidence. However it displays marked anticholinergic activity. There have been reports of hepatotoxicity, also in patients with previously normal hepatic function, due to chlorpromazine. Alimemazine and triflupro-mazine are other representatives from this group. 

The piperazines include fluphenazine, trifluoperazine, prochlorperazine, perazine and perphenazine. They are agents with a high antipsychotic potency with less pronounced anticholinergic effects. However their potential to produce extrapyramidal effects is more pronounced. 

The piperidines, e.g. thioridazine, pipothiazine and pericyazine, have the lowest potential to cause extrapyramidal effects. Thioridazine is one of the most sedative phenothiazines. It may decrease the inotropic activity of digitalis by its quinidine-like action, which can cause myocardial depression, decreased efficiency of repolarization, and increased risk of tachyarrhythmias. With thioridazine drug induced sexual dysfunction and especially cardiotox-icity with prolongation of the QT-interval are more frequently seen than with other phenothiazines. For the above reasons thioridazine is withdrawn from the market in many countries. 

The heterocyclic antipsychotic agent, risperidone, is a benzisoxazole derivative with antiserotoner-gic (5-HT2) as well as antidopaminergic (D2) activity. Risperidone is also considered to be a so-called quantitatively atypical antipsychotic agent because in low doses it has few extrapyramidal effects. 

Aggravation of the extrapyramidal effects of antipsychotic agents have been described and it has been reported that the use of lithium in combination with haloperidol may result in irreversible neurological toxicity. Lithium can increase the hypothyroid effects of antithyroid agents or iodides. 

Mechanism of Action A phenothiazine that blocks dopamine neurotransmission at postsynaptic dopamine receptor sites. Possesses strong anticholinergic, sedative, and antiemetic effects moderate extrapyramidal effects and slight antihistamine action. Therapeutic Effect Relieves nausea and vomiting improves psychotic conditions controls intractable hiccups and porphyria. 

Mechanism of Action A phenothiazine that antagonizes dopamine neurotransmission at synapses by blocking postsynaptic dopaminergic receptors in the brain. Therapeutic Effect Decreases psychotic behavior. Also produces weak anticholinergic, sedative, and antiemetic effects and strong extrapyramidal effects. Pharmacokinetics Erratic absorption. Protein binding greater than 90%. Metabolized in liver. Excreted in urine. Half-life 33 hr. 

Akathisia, dystonic extrapyramidal effects, parkinsonian extrapyramidal effects, tardive dyskinesia, blurred vision, ocular changes, constipation, decreased sweating, dry mouth, nasal congestion, dizziness, drowsiness, orthostatic hypotension, urinary retention, somnolence... 

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