A 32-year-old man with opioid addiction presents with cough due to a viral infection. What is the appropriate symptomatic treatment for his cough?

The selection of benzonatate for the symptomatic treatment of cough in this patient is appropriate due to several reasons. Benzonatate is a non-narcotic cough suppressant that works by anesthetizing the stretch receptors in the lungs and pleura, reducing the urge to cough. This is particularly advantageous for a patient with a history of opioid addiction, as avoiding narcotic-based cough treatments helps to minimize the risk of relapse or further substance dependency.

In contrast, the other options include medications that pose risks or may not be suitable. Guaifenesin/dextromethorphan contains dextromethorphan, which is an antitussive but can have potential for misuse, especially in individuals with a background of substance abuse. Although guaifenesin is an expectorant and could help with mucus clearance, the inclusion of dextromethorphan would not be optimal in this context.

Guaifenesin combined with codeine includes an opioid component, which is contraindicated in a patient with opioid addiction due to the high risk of addiction and adverse effects associated with opioid use.

Montelukast is primarily an anti-inflammatory medication used for asthma and allergic rhinitis, and is not indicated for the treatment