USMLE Pharmacology MCQS

01. Sodium Bicarbonate and Phenytoin are used to reduce the toxicity of one of the following drugs?
A. Physostigmine
B. Atropine
C. Warfarin
D. Desipramine

Answer: D. Desipramine


02. Which one of the following drugs is used to treat the toxicity of Amitriptyline?
A. Warfarin
B. Sodium Bicarbonate
C. Phenytoin
D. Flumazenil 
E. B & C 


Answer:  E. B & C 
Sodium Bicarbonate is used to maintain the alkalinization of arterial PH.
While Phenytoin is used to control seizures. We can replace Phenytoin with Fosphenytoin to reduce the risk of hypotension caused by Phenytoin.


03. Which one of the following drugs is an ultra Short-acting barbiturate?
A. Phenobarbital
B. Amobarbital
C. Thiopental
D. A & B 

Answer: C. Thiopental

04. A barbiturate drug that has a duration of action of 1-2 days is one of the following?
A. Pentobarbital
B. Thiopental
C. Secobarbital
D. Phenobarbital


Answer: D. Phenobarbital


05. Which one of the following barbiturate drugs has a duration of action of 20 minutes?
A. Pentobarbital
B. Secobarbital
C. Thiopental
D. Phenobarbital


Answer: C. Thiopental


06. Which one of the following barbiturate drugs has a duration of action of 3-8 hours?
A. Pentobarbital
B. Secobarbital
C. Amobarbital
D. A & B 
E. All of the above


Answer: E. All of the above
Thiopental is a barbiturate that enhances GABAergic transmission thus increasing the duration of chloride channel opening. 


07. 20 minutes is the duration of action of one of the following barbiturate drugs?
A. Phenobarbital
B. Pentobarbital
C. Thiopental
D. Amobarbital


Answer: C. Thiopental


08. 1-2 days is the duration of action of one of the following barbiturate drugs?
A. Thiopental
B. Amobarbital
C. Pentobarbital
D. Phenobarbital


Answer: D. Phenobarbital


09. Which one of the following drugs has a narrow therapeutic index?
A. Amitriptyline
B. Desipramine
C. Citalopram
D. A & B
E. All of the above


Answer: A. Amitriptyline

10. Which one of the following antidepressant drugs has a narrow therapeutic index?
A. Sertraline
B. Fluvoxamine
C. Paroxetine
D. Nortriptyline


Answer: D. Nortriptyline

11. Antidepressant drug with a wide therapeutic index is one of the following?
A. Amitriptyline
B. Trimipramine
C. Doxepin
D. Fluoxetine


Answer: D. Fluoxetine

Selegiline
it's an MAO type B inhibiting agent which metabolizes dopamine thus decreasing the metabolism of dopamine leading to an increased level of dopamine in the CNS. When selegiline is given at higher doses it loses its selectivity and causes severe hypertension.

12. Entacapone and Tolcapone are used in Parkinson's disease. Which one of the following statements about the functions of Tolcapone is wrong?
A. Reversible inhibitors of COMT
B. Tolcapone does not penetrate the blood-brain barrier 
C. Tolcapone has a long duration of action
D. Tolcapone causes fulminating hepatic necrosis
E. Both B & C

Answer: Tolcapone does not penetrate the blood-brain barrier 


13. Wearing-off phenomena are linked with which of the following drugs?
A. Entacapone
B. Tolcapone
C. Levodopa
D. Amantadine

Answer: C. Levodopa


14. Which of the following statements is false about Levodopa?
A. Long-term use causes Dyskinesia
B. On an empty stomach, rapidly absorbed
C. Cause an increase in Blood pressure
D. Large doses are required when given alone
E. Vitamin B6 (pyridoxine) decreases its effects

Answer: C. Causes an increase in Blood pressure

15. Which of the following statements about the use of selegiline is wrong?
A. Metabolized to amphetamine
B. Low doses inhibit MAO type A selectively
C. Reduce the required dose of Levodopa
D. Decrease the metabolism of dopamine
E. Both C & D

Answer: B. Low doses inhibit MAO type A selectively (They inhibit MAO type B at low doses)

16. Which one of the following statements about the use of Rasagiline is wrong?
A. Irreversible inhibitor of MAO type B
B. Low doses have selectivity for MAO type B
C. Low potency than selegiline
D. Not metabolized to amphetamine
E. Both B & D

Answer: C. Low potency than selegiline

17. If a person is taking MAO inhibitors, which one of the following drug's concentrations is increased and becomes a strong vasopressor?
A. Tyramine
B. Amphetamine
C. Metaproterenol
D. Methoxamine

Answer: A. Tyramine

18. Which one of the following drugs is used for narcolepsy and to control appetite?
A. Tyramine
B. Amphetamine
C. Metaproterenol
D. Methoxamine

Answer: B. Amphetamine

19. Which one of the following drugs is a 5 times more potent irreversible and selective inhibitor of brain MAO type B drug than selegiline?
A. Amantadine
B. Carbidopa
C. Rasagiline
D. Ropinirole
E. Entacapone

Answer: C. Rasagiline

20. ________ is an effective drug against partial & generalized tonic-clonic seizures?
A. gabapentin
B. pregabalin
C. felbamate
D. lacosamide 

Answer A. Gabapentin

21. Fulminating hepatic necrosis is associated with?
A. Tolcapone
B. Entacapone
C. Aspirin
D. Metformin
E. Both A & B

Answer: A. Tolcapone

22. Which of the following drugs potentiate the effect of the antihypertensive drug propranolol?
A. Phenytoin
B. Rifampicin
C. Paroxetine
D. Ritonavir
E. Both C & D

Answer: E. Both C & D

23. Which one of the following drugs stimulates the metabolism of propranolol adrenergic antagonists leading to a decrease in its effect?
A. Cimetidine
B. Paroxetine
C. Ritonavir
D. Fluoxetine
E. Phenytoin

Answer: E. Phenytoin

24. Peripheral vasospasm is caused by one of the following drugs?
A. Carbidopa 
B. Entacapone
C. Ropinirole 
D. Bromocriptine
E. Amantadine

Answer: D. Bromocriptine 
Because Bromocriptine is a dopamine receptor agonist that causes vasospasm and it's contraindicated in patients suffering from peripheral vascular disease. 
Ropinirole
 it is also a directly stimulating dopamine receptor agonist but doesn't cause vasospasm. if we talk about other drugs, Amantadine is an antiviral drug used for the treatment of influenza as well as for antiparkinsonian action. Because it increases the release of dopamine and inhibits NMDA type of glutamate receptors.
Carbidopa 
it does not cross the BBB, it inhibits the decarboxylase enzyme thus increasing the effect of Levodopa on the CNS. Carbidopa decreases the metabolism of Levodopa in the Peripheral tissues and in the GIT.

Entacapone
Entacapone inhibits the COMT, increasing the uptake of Levodopa in the CNS.

25. Which one of the following drugs is contraindicated in patients suffering from peripheral vascular disease?
A. Carbidopa 
B. Entacapone
C. Ropinirole 
D. Bromocriptine
E. Amantadine 

Answer: D. Bromocriptine

26. Which one of the following drugs has gastrointestinal discomfort except?
A. Zanamivir 
B. Oseltamivir
C. Amantadine
D. Rimantadine 
E. None of these 

Answer: A. Zanamivir 
Because this drug is not active orally and is either inhaled or administered intranasally.

27. Which one of the following statements about Parkinson's disease is wrong?
A. Characterized by bradycardia
B. Acetylcholine overactive by stimulatory neurons
C. Phenothiazine and haloperidol is contraindicated
D. Fluorodopa used in  positron emission tomography (PET) for visualized
E. GABA is secreted by cells of substantia nigra back to the neostriatum

Answer: E. GABA is secreted by cells of substantia nigra back to the neostriatum

28. Which one of the following drugs is the oldest currently available antiseizure drug?
A. oxcarbazepine
B. carbamazepine
C. phenobarbital
D. primidone 

Answer: C. Phenobarbital

(High dose of Beta lactams especially imipenem causes seizures)

29. Which one of the following triptan drugs is the longest-acting drug with a half-life of more than 24 hours?
A. Almotriptan
B. Sumatriptan
C. Frovatriptan
D. Rizatriptan 


Answer: Frovatriptan 

30. Which one of the following drugs has an action on Dihydroorotate dehydrogenase ( DHODH)?
A. Frovatriptan
B. Methotrexate
C. Auranofin
D. Leflunomide


Answer: D. Leflunomide