A patient begins taking the calcium channel blocker, nifedipine [Procardia], along with metoprolol, to treat hypertension. The nurse understands that metoprolol is used to:

Choice A reason: Red-orange colored bodily secretions are a well-known side effect of the medication rifampin, not isoniazid. Rifampin, often used in combination therapy for tuberculosis, can cause bodily fluids such as urine, sweat, and tears to turn a red or orange color. However, isoniazid does not cause this specific discoloration and is more commonly associated with different side effects.

Choice B reason: Tingling sensation in fingers and toes, also known as peripheral neuropathy, is a recognized side effect of isoniazid. This medication can interfere with the metabolism of vitamin B6 (pyridoxine), leading to a deficiency that causes neuropathy. Patients taking isoniazid are often prescribed vitamin B6 supplements to prevent or mitigate this side effect. Peripheral neuropathy presents as tingling, numbness, or burning sensations, especially in the extremities, and taking vitamin B6 helps to alleviate these symptoms.

Choice C reason: Difficulty distinguishing the color red from green, or color blindness, is not a known side effect of isoniazid. Color vision deficiency is not typically associated with the use of isoniazid. Other medications, such as ethambutol, used in tuberculosis treatment can affect color vision, but isoniazid primarily causes peripheral neuropathy and liver toxicity rather than visual disturbances.

Choice D reason: Light sensitivity, or photophobia, is not commonly associated with isoniazid use. This symptom is more likely linked to conditions or medications affecting the eyes or central nervous system. Isoniazid's side effects are mainly related to liver toxicity and peripheral neuropathy, not to light sensitivity.

Choice A reason: Amphotericin B is typically administered intravenously because it is poorly absorbed from the gastrointestinal tract and thus not suitable for oral administration. It is used to treat severe systemic fungal infections and is known for its potential nephrotoxicity and other adverse effects.

Choice B reason: Azoles, such as fluconazole and itraconazole, generally have lower toxicity compared to amphotericin B. They are often used as first-line treatments for many fungal infections due to their safer side effect profile. Azoles work by inhibiting the synthesis of ergosterol, an essential component of fungal cell membranes, and are available in both oral and intravenous formulations, making them more versatile in their use.

Choice C reason: While amphotericin B does have some drug interactions, it is not typically known for significantly increasing the levels of many other drugs. Instead, the primary concern with amphotericin B is its potential for nephrotoxicity and other direct adverse effects on the patient.

Choice D reason: Both amphotericin B and azoles are considered broad-spectrum antifungal agents. Amphotericin B is effective against a wide range of fungi, including many that are resistant to other antifungal agents. Azoles are also broad-spectrum and are used to treat a variety of fungal infections, but they generally have a better safety profile than amphotericin B.