Review of Pharmacology - 9E (2015)

Review of Pharmacology
• It is active at µ receptors and side effects are similar to those of morphine.
• Dezocine doesn’t increase plasma histamine and produces less hypotension than morphine or pentazocine.
• Dezocine is effective for moderate to severe pain but can cause myocardial depression.
314. Ans. (d) Subarachnoid (Ref: KDT 6/e p458, 437; Lee 12th/76-77)
• Respiratory depression occurs due to depression of respiratory centre by morphine travelling through the subarachnoid
space (intrathecal route)
Routes of administration of morphine are:
––
Oral
––
Rectal
––
Intramuscular
––
Intravenous
––
Transdermal
––
Extradural/Epidural
––
Subcutaneous
Central Nervous System
315. Ans. (b) Rectal; (c) SC: (d) IV; (e) IM (Ref: KDT 6/e p458; Lee 12th/76)
316. Ans. (a) It is an opioid antagonist; (c) It is used in alcohol dependence; (d) It is used to treat opioid dependence (Ref:
KDT 6/e p467)
317. Ans. (a) Acetaldehyde (Ref: KDT 6/e p386)
• Disulfiram is an aldehyde dehydrogenase inhibitor that can be used for de-addiction of chronic alcoholics.
Alcohol
Aldehyde
Ethyl alcohol Acetaldehyde Acetic acid
dehydrogenase
dehydrogenase
Due to inhibition of aldehyde dehydrogenase, there is accumulation of acetaldehyde that leads to several distressing
symptoms (which strengthens the resolution of a person to quit alcohol).
318. Ans. (d) Antagonist of opioid receptors (Ref: KDT 6/e p467)
• Naltrexone is used to decrease the craving for alcohol after de-addiction.
319. Ans. (d) Pethidine (Ref: KD Tripathi 6/e p440)
Most of pethidine is metabolized by MAO-A and is inactivated. Small amount is converted to nor-pethidine, which has
CNS stimulant properties. Therefore, if combined with MAO inhibitors, most of pethidine will form nor-pethidine and the
risk of seizures will increase.
320. Ans. (c) Alcoholics psychologically but not physically dependent on alcohol (Ref: KDT 6/e p387)
• If a patient is physically dependent on alcohol, disulfiram can precipitate severe withdrawl symptoms. It is therefore,
not indicated for physically dependent alcoholics.
321. Ans. (c) Inhibits the metabolism of methanol and generation of toxic metabolite (Ref: KDT 6/e p387)
• Methanol produces toxic metabolites (formaldehyde and formic acid) that are responsible for blindness. This metabolism
takes place with the help of alcohol and aldehyde dehydrogenase.
Alcohol
Aldehyde
Methanol Formaldehyde Formic acid
dehydrogenase
dehydrogenase
• Ehtanol is also metabolized by the same enzymes to produce acetaldehyde and acetic acid. It competes with methanol
for above enzymes and inhibits the generation of toxic formaldehyde and formic acid.
322. Ans. (d) Fomepizole (Ref: KDT 6/e p387)
323. Ans. (a) Ischemic heart disease patients (Ref: KDT 6/e p457)
• Morphine is used for the treatment of myocardial infarction (ischemic heart disease) and LVF.
• Morphine is contra-indicated in extremes of age i.e., very young and elderly persons.
• It is also contra-indicated in bronchial asthma because it can cause respiratory depression and worsen the condition.
• By increasing intrabiliary pressure, morphine can worsen the pain of biliary colic.
324. Ans. (a) Tramadol (Ref: KDT 6/e p460)
325. Ans. (a) Pentazocine (Ref: KDT 6/e p464, 465)
Pentazocine can cause dysphoric reactions (hallucinations) by stimulating the k receptors.
390
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