Q- Ingestion of mushroom containing pilocarpine may cause which one of the following side effects?
A- Bronchodilation
B- Diarrhea
C- Hypertension
D- Tachycardia
B- Diarrhea- Some species of mushroom contains pilocarpine. It stimulates M receptors (parasympathomimetic effect) which cause diarrhea, bronchoconstriction, bradycardia and hypotension.
Q- In adrenergic synapses, increasing the concentration of norepinephrine leads to which one of the following?
A- Activation of dopa decarboxylase
B- Activation of presynaptic G coupled receptors
C- Increased release of norepinephrine
D- Stimulation of monoamine oxidase
B- Activation of presynaptic G coupled receptors- These receptors are considered autoregulatory to inhibit further neurotransmitter release and decreased synthesis of norepinephrine.
Q- Which one of the following is the mechanism of action of N-acetylcysteine in treating a case of acetaminophen toxicity?
A- Blocks metabolism of acetaminophen
B- Enhances clearance of acetaminophen
C- Induces P450 enzymes
D- Supplies sulfhydryl group to detoxify the drug metabolite
D- Supplies sulfhydryl group to detoxify the drug metabolite- Most acetaminophen is metabolized by glucuronidation into inactive metabolite. In high doses, cytochrome P450 may convert acetaminophen to reactive metabolite that may damage the liver. N-acetylcysteine supplies sulfhydryl groups to bind to this reactive metabolite and inactivate it.
