A client presents to the healthcare setting with a diagnosis of emphysema. Which of the following medications below would be contraindicated with the client's allergy to soybeans?

A) Cetirizine (Zyrtec): This medication is classified as a second-generation antihistamine. Second-generation antihistamines are designed to be less sedating than first-generation agents, as they are less likely to cross the blood-brain barrier. Cetirizine effectively alleviates symptoms of allergic rhinitis by blocking histamine receptors and is commonly used due to its efficacy and reduced sedation compared to older antihistamines.

B) Chlorpheniramine (Aller-Chlor): Chlorpheniramine is a first-generation antihistamine. It tends to cause more sedation and has a higher likelihood of causing side effects such as drowsiness, dry mouth, and dizziness. First-generation antihistamines are typically less selective and can affect the central nervous system more significantly than their second-generation counterparts.

C) Diphenhydramine (Benadryl): This medication is also a first-generation antihistamine. It is well-known for its sedative effects and is often used for allergic reactions, as well as for its sleep-inducing properties. Like other first-generation antihistamines, diphenhydramine can cause significant drowsiness and other anticholinergic effects.

D) Montelukast (Singulair): Montelukast is not an antihistamine but rather a leukotriene receptor antagonist. It is used for the management of allergic rhinitis and asthma but works through a different mechanism by blocking leukotriene receptors, thereby reducing inflammation and mucus production. It is not classified as an antihistamine, either first or second generation.

A) Liver injury: Zafirlukast (Accolate) has been associated with the risk of liver injury. It is important for clients to be informed about this potential adverse effect, as it may require monitoring of liver function tests during treatment. Symptoms of liver injury, such as jaundice, dark urine, or severe fatigue, should prompt clients to seek medical attention.

B) Bradycardia: Bradycardia is not a commonly associated adverse effect of zafirlukast. This medication primarily works as a leukotriene receptor antagonist and does not typically affect heart rate significantly. Clients should be aware of other more relevant side effects rather than bradycardia.

C) Renal failure: Renal failure is not a known adverse effect of zafirlukast. While kidney function should always be monitored in patients taking various medications, zafirlukast specifically does not have a direct association with renal failure.

D) Bronchoconstriction: While bronchoconstriction is a concern in asthma management, zafirlukast is designed to prevent bronchoconstriction by blocking leukotriene receptors. Therefore, it is not an adverse effect of the medication. In fact, its purpose is to help reduce the incidence of bronchoconstriction and improve asthma control.