What medication should the nurse anticipate will be prescribed for a client diagnosed with severe acne vulgaris?

Isotretinoin is recognized as a highly effective treatment for severe acne vulgaris, particularly in cases where other therapies have failed or in situations where the acne is particularly aggressive and can lead to scarring. This medication is a retinoid, which works by decreasing the size and activity of sebaceous glands, reducing oil production, and preventing the formation of acne lesions. Its effectiveness and specificity for acne vulgaris make it the go-to choice when treating severe manifestations of the condition.

On the other hand, acyclovir is an antiviral medication primarily used to treat herpes virus infections, ketoconazole is an antifungal that treats fungal infections, and ethambutol is an antibiotic specifically used for tuberculosis. None of these alternatives target the underlying causes of severe acne vulgaris, thereby affirming why isotretinoin is the anticipated medication for such a diagnosis.