Correct Answer: D

Rationale: Anti-epileptic drugs (AEDs) are often used in the management of migraine headaches due to their ability to help prevent or reduce the frequency and intensity of migraines. They work by stabilizing electrical activity in the brain, which can help in controlling migraine symptoms. While beta-blockers are also sometimes used in migraine prevention, anti-epileptic drugs are more commonly associated with migraine treatment.

Correct Answer: A

Rationale: The therapeutic effect of lithium is that it prevents or decreases the incidence of acute manic episodes in patients with bipolar disorder. Lithium is commonly used as a mood stabilizer in the treatment of bipolar disorder due to its ability to reduce the frequency and severity of manic episodes.

Correct Answer: C

Rationale: Lithium is typically administered orally to ensure proper absorption and distribution in the body. It is important to follow the prescribed route of administration to achieve the desired therapeutic effect and avoid potential adverse effects.

Correct Answer: D

Rationale: A therapeutic response to levothyroxine is indicated by a decrease in the level of TSH. This decrease signifies that the body requires less stimulation to produce thyroid hormone, reflecting a normalization of thyroid function due to the medication's effectiveness.

Correct Answer: C

Rationale: In the case of a UTI, a sensitivity test is crucial as it identifies the most effective antibiotic to target the specific microorganism causing the infection. This test helps in prescribing the appropriate antibiotic for successful treatment and preventing antibiotic resistance.