Trimethoprim:

Correct Answer: B

Rationale: Trimethoprim inhibits dihydrofolate reductase, not activates it, blocking folate synthesis in bacteria, so that's false. It's a weak base, a true statement, aiding its concentration in acidic environments like urine. It has good prostate penetration, effective in prostatitis, making that false. It distributes into CSF, useful in meningitis, so that's incorrect. It's teratogenic, not harmless in pregnancy. Its basic nature enhances its antibacterial efficacy, a key pharmacokinetic advantage in urinary tract infections.

Correct Answer: A

Rationale: Chronic high-dose caffeine cessation causes withdrawal. Lethargy -reflects reduced adenosine blockade, leading to fatigue. Migraine , nausea , and vomiting (E) may occur, but lethargy is most common. Tinnitus isn't typical. His 20-year habit predicts this CNS depression.

Correct Answer: C

Rationale: One major side effect to monitor in a patient taking Lithium for bipolar I disorder is the risk of seizures. Lithium is known to lower the seizure threshold, increasing the likelihood of seizures occurring, especially if the patient has any pre-existing risk factors for seizures. Therefore, it is critical to closely monitor patients on Lithium for any signs or symptoms of seizures and promptly address them if they occur to prevent any complications. Monitoring lithium levels and maintaining them within the therapeutic range can also help reduce the risk of seizures.

Correct Answer: A

Rationale: Diazepam undergoes enterohepatic recirculation, contributing to its prolonged duration of action.

Correct Answer: D

Rationale: Before antidepressants, assessing suicidal ideation is vital due to depression's suicide risk and SSRIs' potential to increase it initially. This ensures safety and guides monitoring. Alcohol use , allergies , and duration matter but are secondary to immediate risk. D prioritizes life-saving assessment, making it the most important question.