Which of the following drugs is an antithyroid medication?

Choice A rationale

Selective serotonin reuptake inhibitors (SSRIs) inhibit the reuptake of serotonin, leading to increased serotonin concentrations in the synaptic cleft. However, this process and the subsequent downregulation of presynaptic receptors require time. Tricyclic antidepressants also have a delayed onset of action, and SSRIs do not work faster; they are generally preferred due to a more favorable side effect profile.

Choice B rationale

The therapeutic effects of SSRIs are not immediate. It takes time for the central nervous system to adapt to the increased serotonin levels. This process involves changes in receptor sensitivity and gene expression. Patients must be taught that it can take several weeks for the full antidepressant effects to become apparent, and they should not be discouraged if they don't feel better right away.

Choice C rationale

SSRIs are a first-line treatment for a variety of depressive disorders, including severe depression. Their efficacy is well-established in clinical practice and they are often used in conjunction with psychotherapy. The notion that they are not effective for severe cases is inaccurate; they have demonstrated efficacy across a spectrum of depression severity.

Choice D rationale

The therapeutic effect of SSRIs is not immediate because it takes time for the brain to adapt to the increased serotonin levels in the synapse. This process involves neuroplastic changes, including the downregulation of presynaptic autoreceptors, which can take several weeks to occur. Therefore, it is crucial to inform patients that it may take 4 to 6 weeks to experience the full beneficial effect.

Choice A rationale

Increasing the dose of losartan would exacerbate the patient's dizziness and hypotension. Losartan, an angiotensin II receptor blocker (ARB), works by blocking the vasoconstrictive effects of angiotensin II, leading to vasodilation and a decrease in blood pressure. An increased dose would lead to more profound vasodilation, resulting in an even greater drop in blood pressure and worsening orthostatic hypotension. This could increase the risk of falls and injury.

Choice B rationale

Losartan is a vasodilator, and its action can lead to a drop in blood pressure, especially when a person moves from a sitting or lying position to a standing position, a condition known as orthostatic hypotension. The dizziness is a symptom of this sudden drop in blood pressure. Changing positions slowly allows the body's baroreceptor reflex to compensate and regulate blood pressure, thus mitigating the orthostatic effect and preventing falls.

Choice C rationale

Taking losartan with food does not significantly alter its absorption or a patient's risk of orthostatic hypotension. Losartan can be taken with or without food. However, this action does not address the underlying physiological mechanism of orthostatic hypotension, which is a common side effect of this class of antihypertensive medications. The dizziness is directly related to the vasodilation effect, not food intake.

Choice D rationale

Discontinuing losartan abruptly without consulting a healthcare provider can be dangerous. It could lead to a rebound increase in blood pressure, or a hypertensive crisis, which can increase the risk of stroke or myocardial infarction. The patient should be advised to manage the side effect by changing position slowly, and if symptoms persist, they should consult their healthcare provider to discuss alternative medication options or dose adjustments.