Which allergies should alert the nurse to hold montelukast?

Montelukast, a medication commonly used to manage asthma and allergies, is typically well tolerated. However, it is essential to consider the patient's allergy history when prescribing any medication to avoid adverse reactions.

In this instance, allergies to lactose and cellulose, as indicated in the correct choice, would be pertinent since montelukast tablets may contain these substances as excipients. Allergies to these compounds may lead to gastrointestinal symptoms or allergic reactions when the medication is ingested, necessitating caution or alternative therapies for those patients.

The other choices, such as penicillin and sulfa, or shellfish and peanuts, are less relevant in the context of montelukast because they are not typically associated with the ingredients in this medication. While these additional allergies may indicate a broader allergic predisposition, they do not specifically warrant holding montelukast. Thus, being aware of lactose and cellulose allergies is crucial for patient safety and medication compliance.