Term
| In clinical psychiatry, what is the common indication for treatment with anticholinergics and/or amantadine? |
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Definition
| The treatment of medication-induced movement disorders, particularly neuroleptic-induced parkinsonism or dystonia, and medication-induced postural tremor. |
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Term
| What are the names of the six anticholinergics? |
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Definition
Benztropine
Biperiden
Ethopropazine
Orphenadrine
Procyclidine
Trihexyphenidyl |
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Term
| What receptors are targeted by anticholinergics? |
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Definition
All anticholinergics block muscarinic acetylcholine receptors.
Benztropine also has some antihistaminergic effects.
None of the available anticholinergic drugs has any effects on the nicotinic acetylcholine receptors. |
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Term
| What is the major cause of adverse effects in anticholinergic treatment? |
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Definition
| Blockade of muscarinic receptors |
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Term
| What are the CI to treatment with anticholinergics? |
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Definition
Should be used with caution, if at all in:
Patients with prostatic hypertrophy
Urinary retention
Narrow-angle glaucoma |
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Term
| What are the signs and symptoms of anticholinergic intoxication? |
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Definition
Delirium, coma, seizures, agitation, hallucinations
Severe hypotension, SVT
Flushing, mydriasis, dry skin, hyperthermia, decreased bowel sounds |
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Term
| What is the management of suspected anticholinergic intoxication? |
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Definition
Immediate discontinuation of anticholinergics.
Diagnose with physostigmine 1-2mg IV or IM.
Treatment with physostigmine only in severe cases and when cardiac monitoring and life-support are available - may lead to severe hypotension and bronchial constriction. |
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Term
| Which other drugs have anticholinergic activity that may cause anticholinergic intoxication if co-administered with anti-cholinergics? |
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Definition
DRAs
TCAs
MAOIs
Many other perscription and over-the-counter cold preparations |
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Term
| How may anticholinergics interfere with drug absorption in the GIT? |
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Definition
| May delay gastric emptying, thereby decreasing the absorption of drugs that are broken down in the stomach and usually absorbed in the duodenum (e.g. levodopa, DRAs). |
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Term
| Which two populations have higher concentrations of amantadine? |
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Definition
Elderly - twice as high as in young adults
Renal failure - since amantadine is excreted in urine |
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Term
| What is the mechanism of action of amantadine? |
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Definition
| It augments dopaminergic neurotransmission in the CNS. The exact mechanism is unknown. |
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Term
| How does amantadine compare to anticholinergics? |
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Definition
As effective as anticholinergics for the treatment of akinesia, parkinsonism and rabbit syndrome caused by antipsychotics.
Less effective in treatement of acute dystonia.
Not effective in treating tardive dyskinesia and akathisia. |
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Term
| What clinical settings are best suited for treatment with amantadine? |
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Definition
| Persons with extrapyramidal symptoms who would be sensitive to additional anticholinergic effects, especially those taking a low-potency DRA or the elderly. |
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Term
| What are the 8 common CNS side-effects of amantadine? |
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Definition
Common (5-10%): mild dizziness, insomnia, impaired concentration
Uncommon (1-5%): irritability, depression, anxiety, dysarthria, ataxia |
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Term
| What 2 rare CNS adverse effects have been reported with amantadine? |
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Definition
Seizures
Psychotic symptoms |
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Term
| What is the most common peripheral adverse effect of amantadine? |
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Definition
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Term
| Which special dermatological adverse effect is noted in amantadine? |
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Definition
| Livedo reticularis - a purple discoloration of the skin. Reported in <5% of patients taking the drug for >1m. Usually diminishes with elevation of the legs, and always resolves with discontinuation. |
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Term
| What are the 5 CI to amantadine treatement? |
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Definition
1. Renal disease
2. Seizure disorder
Should be used with caution...
3. Edema
4. Cardiovascular disease
5. Pregnancy |
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Term
| What is a common cause of amantadine toxicity? What are the symptoms? |
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Definition
| Suicide attempts with amantadine overdosages are life threatening. Symptoms can include toxic psychoses (confusion, hallucinations, aggressiveness) and cariopulmonary arrest. |
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