A patient will be receiving oral theophylline (Theo-Dur), 600 mg/day, in three divided doses.

Identify how many milligrams the patient will receive per dose.

Choice A rationale

Ethambutol, an antitubercular medication, is known to cause optic neuritis as a significant adverse effect. This condition manifests as inflammation of the optic nerve, leading to decreased visual acuity, red-green color discrimination impairment, and even blindness. Therefore, regular monitoring of visual acuity and color vision is crucial throughout the duration of ethambutol therapy.

Choice B rationale

Skin color changes are not a primary adverse effect of ethambutol. While some antitubercular drugs like rifampin can cause orange-red discoloration of bodily fluids, ethambutol's adverse effect profile primarily targets the ocular system. Monitoring skin color would not be an effective or necessary assessment for ethambutol therapy.

Choice C rationale

While overall renal function is important for drug excretion, ethambutol does not typically cause significant changes in urine output. It is primarily excreted renally, and dose adjustments may be needed in renal impairment, but direct monitoring of urine output as a specific adverse effect of ethambutol is not the primary concern.

Choice D rationale

Cardiac rhythm disturbances are not a commonly associated adverse effect of ethambutol. Antitubercular medications like isoniazid can rarely cause cardiac issues, but ethambutol's predominant and significant toxicity is to the optic nerve. Therefore, monitoring cardiac rhythm is not a routine or primary assessment for ethambutol therapy.

Choice A rationale

Treatment for pulmonary tuberculosis with rifampin is typically prolonged, lasting for several months, often 6 to 9 months, not just 1 month. Shortening the treatment duration significantly increases the risk of drug resistance and recurrence of the infection. Adherence to the full regimen is critical for eradication.

Choice B rationale

Rifampin is not typically associated with causing insomnia. Common side effects include gastrointestinal upset, hepatotoxicity, and discoloration of body fluids. Insomnia is more commonly linked to other medications or underlying conditions, not a characteristic side effect of rifampin directly impacting sleep architecture.

Choice C rationale

Taking rifampin with meals is generally not recommended as food can impair its absorption, reducing its bioavailability and therapeutic effectiveness. It is typically advised to take rifampin on an empty stomach, either 1 hour before or 2 hours after meals, to ensure optimal drug absorption and efficacy.

Choice D rationale

Rifampin causes a harmless but noticeable orange-red discoloration of urine, sweat, tears, and other body secretions. This is due to the drug's inherent color and its excretion pathways. Clients should be informed of this expected side effect to prevent anxiety and ensure adherence to the medication regimen.