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Pharmacology MCQs- 297

Q- Extrapyramidal side effects develop after the use of haloperidol due to its effect on which of the following receptors?

A- Alpha-adrenergic receptors

B- Dopamine receptors

C- Muscarinic receptors

D- Nicotinic receptors

B- Dopamine receptors- Due to its action to block dopamine receptors, haloperidol administration may cause extrapyramidal side effects such as Parkinsonism-like syndrome, akathisia, dystonia and others.



Q- Which of the following is the main action of carbidopa when it is used in combination with levodopa in the management of Parkinsonism?

A- It increases the absorption of levodopa

B- It increases the permeability of blood-brain barrier to levodopa

C- It inhibits the conversion of levodopa to dopamine peripherally

D- It reduced levodopa side effects such as hypotension

C- It inhibits the conversion of levodopa to dopamine peripherally- This action allows more levodopa to cross the BBB. Without carbidopa, most of the administered levodopa would be converted into dopamine which is not able to cross the BBB so, only a small amount of levodopa would reach the brain.



Q- Which one of the following anti-hypertensive medications is contraindicated in pregnancy?

A- Labetalol

B- Methyldopa

C- Nifedipine

D- Ramipril

D- Ramipril- ACE inhibitors are teratogenic and they can damage the fetus. Other listed drugs are safe to use during pregnancy.



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