A nurse is preparing to administer topotecan IV for a client who has metastatic ovarian cancer.
Which of the following medications should the nurse expect to administer to control the adverse effects of topotecan?

Choice A rationale

Bronchospasm is a constriction of the airways, commonly seen in respiratory conditions like asthma. It is mediated by inflammatory responses and smooth muscle contraction in the bronchi. Acetazolamide, a carbonic anhydrase inhibitor, does not typically cause bronchospasm; its primary effects are on fluid and electrolyte balance and intraocular pressure.

Choice B rationale

Constipation is a common gastrointestinal symptom characterized by infrequent or difficult bowel movements. It can be caused by various factors, including dietary habits, medications, and underlying medical conditions. Acetazolamide's mechanism of action, involving inhibition of carbonic anhydrase, does not directly lead to constipation as a significant adverse effect.

Choice C rationale

Diplopia, or double vision, is a visual disturbance where a single object appears as two. It can result from ocular muscle weakness, nerve damage, or other neurological conditions. Acetazolamide's therapeutic effects are on aqueous humor production in the eye to reduce intraocular pressure, but diplopia is not a recognized adverse effect of this medication.

Choice D rationale

Acetazolamide is a carbonic anhydrase inhibitor that promotes the excretion of bicarbonate, sodium, potassium, and water. This diuretic action can lead to metabolic acidosis, hypokalemia (normal range: 3.5-5.0 mEq/L), and hyponatremia (normal range: 135-145 mEq/L) due to increased renal excretion, hence requiring close monitoring of electrolyte balance.

Choice A rationale

Pseudoephedrine is a sympathomimetic agent that primarily acts as a vasoconstrictor and bronchodilator. It does not directly affect kidney function to cause polyuria. In fact, due to its vasoconstrictive properties, it could theoretically decrease renal blood flow, although this is not a common or expected adverse effect leading to increased urine output.

Choice B rationale

Pseudoephedrine's primary mechanism of action involves stimulating alpha- and beta-adrenergic receptors. It does not have a known effect on appetite regulation; it is not typically associated with either increased or decreased appetite. Therefore, an increased appetite is not an expected adverse effect of this medication.

Choice C rationale

Pseudoephedrine is a sympathomimetic drug that stimulates adrenergic receptors, leading to effects similar to sympathetic nervous system activation. This stimulation typically results in tachycardia, not bradycardia. It increases heart rate and contractility, which can be problematic for individuals with pre-existing cardiovascular conditions.

Choice D rationale

As a sympathomimetic, pseudoephedrine causes vasoconstriction by stimulating alpha-1 adrenergic receptors in the arterioles. This widespread vasoconstriction leads to an increase in peripheral vascular resistance, which in turn can elevate blood pressure. Therefore, hypertension is a common and important adverse effect to monitor for, especially in individuals with pre-existing hypertension.