(b) Again, the key word is least. Narcotics, in the form of paregoric (tincture of opium), and Lomotil (loperamide) are over the counter oral preparations for the treatment of diarrhea. Opiates act on receptors in the gut to produce constipation. Thus (b) is obviously wrong. All of the other answers are side effects of opiate administration.

(v) memorize

(b) the only drugs that do this are opioids, and codeine and merperidine are the two opioids on the list. Of the two, codeine is much better at this than meperidine.

(a) They might reword the question in a way that asks you to remember that the specific receptors are the mu receptors.

(c)  So it seems they want you to think that the emetic response to morphine is locally activated, but actually it is an effect produced by morphine acting on the CTZ in the medulla.

(e) memorization. Don’t be fooled by (a)- these drugs are sedating, but this has nothing to do with the decrease in respiratory rate

(a) pinpoint pupils (miosis) and respiratory depression are hallmark opioid overdose effects, so the only distractor is coma or convulsions. If you can’t breathe too well, I guess you might go into a coma!

(e) – again, a memorization question. What happens is that opioids decrease the response of respiratory centers in the brainstem to the carbon dioxide tension of the blood, and also depresses pontine and medullary centers regulating respiratory frequency. Opioids do not cause oxygen apnea, ((a)), they can be convulsive, but not terminally so ((c)), they are stabilizing on the heart and some are actually used in open-heart surgery ((b)), and they do not cause circulatory collapse ((d)).

(e) This is an example of the type of question where the drug class is given. You are asked to not only identify a drug from the list as being from this class, but additionally that it has the properties that are given in the question that distinguish it from the other drugs of the class that are listed as alternatives. In this example, there is only one drug which meets this criterion. All are drugs which act via opiate receptors, but 3 are agonists ((a), (b), (d)), 1 is an antagonist only ((c)). (e) pentazocine is the only drug which has both types of action, and is the one drug left by the process of elimination.

(c) see above

(b) see above

(a) nalorphine and pentazocine are mixed agonist-antagonists, levallorphan is an opioid agonist, as is propoxyphene

(a) reworded version of the preceding question

(d) This is an example of the kind of question that requires that you have memorized a fact about a particular drug, in this case the fact is (d). Methadone you will remember is not an antagonist like naloxone- it is a full agonist with analgesic properties, just like morphine. When taken orally it is not euphoric in addicts, but acts just like morphine to produce tolerance and physical dependence. Withdrawal is less severe than with morphine because methadone has a much longer half life. Facts 1, 2, and 3 would be met by an antagonist such as naloxone, or perhaps even a mixed agonist-antagonist such as pentazocine.

(b) shortened version of the above question