Which of the following medications is used to treat allergic rhinitis by blocking histamine receptors?

Correct Answer: D

Rationale: The correct answer is D because all three medications (Diphenhydramine, Cetirizine, and Loratadine) are antihistamines that work by blocking histamine receptors to relieve symptoms of allergic rhinitis. Diphenhydramine is a first-generation antihistamine, while Cetirizine and Loratadine are second-generation antihistamines with longer durations of action and less sedation. Therefore, choosing all of the above encompasses the various antihistamines commonly used to treat allergic rhinitis effectively.

Correct Answer: A

Rationale: The correct answer is A: Efavirenz. Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) used in HIV/AIDS management by inhibiting the reverse transcriptase enzyme. It works by binding to the enzyme, preventing the conversion of RNA to DNA in the virus. Amoxicillin (B) is an antibiotic used for bacterial infections, Clarithromycin (C) is also an antibiotic for bacterial infections, and Fluconazole (D) is an antifungal medication. These choices do not target the reverse transcriptase enzyme involved in HIV replication, making them incorrect for managing HIV/AIDS.

Correct Answer: B

Rationale: The correct answer is B because tramadol primarily works by inhibiting the reuptake of serotonin and norepinephrine in the brain. This mechanism of action helps to modulate pain signals and increase pain tolerance. Choice A is incorrect because tramadol has weak affinity for opioid receptors. Choice C is incorrect as tramadol does not inhibit prostaglandin synthesis like NSAIDs. Choice D is incorrect as blocking sodium channels is the mechanism of action for local anesthetics, not tramadol.

Correct Answer: A

Rationale: The correct answer is A: Olanzapine. Olanzapine is an atypical antipsychotic that works by blocking dopamine receptors in the brain, reducing dopamine activity and alleviating symptoms of schizophrenia. Citalopram and Fluoxetine are both selective serotonin reuptake inhibitors used to treat depression and anxiety, not schizophrenia. Lorazepam is a benzodiazepine used for anxiety disorders, not schizophrenia. Blocking dopamine receptors is key in managing schizophrenia symptoms, making olanzapine the appropriate choice.

Correct Answer: D

Rationale: The correct answer is D: Venlafaxine. Venlafaxine is a serotonin-norepinephrine reuptake inhibitor (SNRI), which works by blocking the reuptake of serotonin and norepinephrine in the brain, thereby increasing the levels of these neurotransmitters. This helps alleviate symptoms of depression. Rationale: 1. Sertraline (A) is a selective serotonin reuptake inhibitor (SSRI), primarily targeting serotonin. 2. Amitriptyline (B) is a tricyclic antidepressant that primarily acts on norepinephrine and serotonin reuptake, but it is not as selective as Venlafaxine. 3. Citalopram (C) is an SSRI that primarily targets serotonin reuptake, not norepinephrine. In summary, Venlafaxine is the correct choice as it specifically inhibits both serotonin and norepinephrine reuptake