Review of Pharmacology - 9E (2015)

Central Nervous System
258. Ans. (a) Phenothiazines (Ref: KDT 6/e p431)
259. Ans. (a) Osteoporosis (Ref: KDT 6/e p431-432)
260. Ans. (d) Amoxapine (Ref: KDT 6/e p445)
261. Ans. (d) Loxapine (Ref: KDT 6/e p429)
262. Ans. (a) Chlorpromazine (Ref: Katzung 11/e p482)
263. Ans. (d) Tardive dyskinesia (Ref: KDT 6/e p431)
264. Ans. (c) MAO inhibitors (Ref: KDT 6/e p438)
265. Ans. (d) Quetiapine (Ref: KDT 6/e p431)
All other drugs are typical antipsychotics except quetiapine and release prolactin by blocking hypothalamic dopamine
receptors.
266. Ans. (d) Diphenyl butyl piperidine (Ref: Goodman and Gilman 11/e p467)
267. Ans. (a) Aripriprazole (Ref: KDT 6/e p429, 430)
268. Ans. (b) Bupropion (Ref: KDT 6/e p448)
269. Ans. (d) Maprotiline (Ref: KDT 6/e p440)
Maprotiline is a tricyclic antidepressant.
270. Ans. (d) Uncontrolled seizure (Ref: KDT 6/e p448-449)
Tricyclic antidepressants can be used for treatment of
• Depression
• Panic disorder
• Obsessive compulsive disorder
• Chronic neuropathic pain
• Enuresis (incontinence particularly in institutionalized elderly patients)
• Attention deficit hyperkinetic disorder
But currently SSRIs are preferred for most of these indications over tricyclics because of severe adverse effect profile of the
latter. Tricyclics are not indicated for seizures, rather some of them like clomipramine can induce convulsions by lowering
the seizure threshold.
271. Ans. (c) Antimuscarinic drugs reduces its severity (Ref: Principles of Pharmacology by KK Sharma and HL Sharma 1st/466;
KDT 6/e p431-432)
General Central Nervous Pharmacology System
• Tardive dyskinesia, a disorder characterized by oro-buccal-lingual dyskinesia (as if patient is chewing chewing-gum),
is a common complication of long-term neuroleptic (anti-psychotic) drug treatment.
• It is a late complication that occurs due to increased sensitivity of dopaminergic receptors (due to chronic
presence of D 2
antagonists i.e. antipsychotics). Due to increased dopaminergic activity, cholinergic activity
decreases that ultimately results in decreased release of GABA from striatal neurons.
• Thus dopaminergic drugs like levo-dopa and anti-cholinergic drugs like trihexyphenydil will worsen the
symptoms.
• A reduction in dose of the dopamine receptor blocker will also worsen the dyskinesia due to same reason,
while an increase in dose may suppress it.
• The management of Tardive dyskinesia may involve the following strategies:
––
To decrease dopaminergic activity by increasing the dose of anti-psychotic but it is not advisable as
these drugs themselves have resulted in supersensitivity of receptors
––
To increase cholinergic activity by choline or lecithin but the doses required are very high and success
rate is limited (only 20%)
––
To increase the GABA activity by diazepam along with neurolept holiday (i.e. stopping anti-psychotic
and anticholinergic medications).
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