1. Drug-induced dyskinesias
Domina Petric, MD

2. Drug-induced dyskinesias
Levodopa and dopamine agonists produce diverse dyskinesias as a dose-related phenomenon in patients with Parkinson´s disease.
Dose reduction can reverse dyskinesias.
Chorea may also develop in patients receiving phenytoin, carbamazepine, amphetamines, lithium and oral contraceptives.
Dystonia may occur from administration of dopaminergic agents, lithium, SSRIs, carbamazepine and metoclopramide.
Postural tremor: theophylline, caffeine, lithium, valproic acid, thyroid hormone, tricyclic antidepressants, isoproterenol.
Katzung, Masters, Trevor. Basic and clinical pharmacology.

3. Drug-induced dyskinesias
Acute dyskinesia or dystonia precipitated by the first few doses of a phenothiazine can be treated with parenteral administration of:
An antimuscarinic drug (benztropine 2 mg iv.),
diphenhydramine 50 mg iv. or
biperiden 2-5 mg iv. or im.
Katzung, Masters, Trevor. Basic and clinical pharmacology.

4. Katzung, Masters, Trevor. Basic and clinical pharmacology.
Tardive dyskinesia
Variety of abnormal movements, common complication of long-term neuroleptic or metoclopramide drug treatment.
A reduction in dose of the offending medication commonly worsens the dyskinesia.
An increase in dose may suppress it.
Treatment:
depletion of dopamine (reserpine, tetrabenzine)
dopamine receptor blockade (phenothiazines, butyrophenones)
Katzung, Masters, Trevor. Basic and clinical pharmacology.

5. Katzung, Masters, Trevor. Basic and clinical pharmacology.
Tardive dyskinesia
Paradoxically, the dopamine receptor-blocking drugs (antipsychotics) are the very ones that cause the dyskinesia and are used as treatment of dyskinesia.
Katzung, Masters, Trevor. Basic and clinical pharmacology.

6. Katzung, Masters, Trevor. Basic and clinical pharmacology.
Tardive dyskinesia
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Katzung, Masters, Trevor. Basic and clinical pharmacology.

7. Katzung, Masters, Trevor. Basic and clinical pharmacology.
Katzung, Masters, Trevor. Basic and clinical pharmacology.

8. Katzung, Masters, Trevor. Basic and clinical pharmacology.
Tardive dystonia
It is usually segmental or focal.
Generalized dystonia is less common and occurs in younger patients.
Treatment:
reserpine, tetrabenazine
phenothiazines, butyrophenones
anticholinergic drugs
local injection of botulinum A toxin
Katzung, Masters, Trevor. Basic and clinical pharmacology.

9. Katzung, Masters, Trevor. Basic and clinical pharmacology.
Rabbit syndrome
It is another neuroleptic-induced disorder.
It is manifested by rhythmic vertical movements about the mouth.
It may respond to anticholinergic drugs.
Katzung, Masters, Trevor. Basic and clinical pharmacology.

10. Katzung, Masters, Trevor. Basic and clinical pharmacology.
Warning!
Tardive syndromes that develop in adults are often irreversible and have no satisfactory treatment.
Antipsychotic medication should be prescribed only when necessary and should be withheld periodically to assess the need for continued treatment and to unmask incipient dyskinesia!
Thioridazine (phenothiazine with a piperidine side chain) is an effective antipsychotic agent, that causes less likely than most other antipsychotics, extrapyramidal reactions.
Antimuscarinic drugs should not be prescribed routinely in patients receiving neuroleptics: combination may increase the likelihood of dyskinesia.
Katzung, Masters, Trevor. Basic and clinical pharmacology.

11. Neuroleptic malignant syndrome
It is a rare complication of treatment with neuroleptics.
It is characterized by RIGIDITY, FEVER, CHANGES IN MENTAL STATUS and AUTONOMIC DYSFUNCTION.
Symptoms typically develop over 1-3 days and may occur at any time during treatment.
Management of neuroleptic malignant syndrome includes:
Withdrawal of antipsychotic drugs, lithium and anticholinergics!
Reduction of body temperature, rehydration!
Dantrolene, dopamine agonists, levodopa or amantadine may be helpful.
Mortality rate is up to 20%.
Katzung, Masters, Trevor. Basic and clinical pharmacology.

12. Katzung, Masters, Trevor. Basic and clinical pharmacology.
Literature
Katzung, Masters, Trevor. Basic and clinical pharmacology.
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Katzung, Masters, Trevor. Basic and clinical pharmacology.