A client is teaching a client who has a new prescription for hydrochlorothiazide for management of hypertension. Which of the following Instructions should the nurse include?

A) By blocking the effects of histamine in the body:
Antihistamines are pharmacological agents that work by antagonizing the effects of histamine, a chemical mediator released by mast cells and basophils in response to allergens or other triggers. Histamine contributes to various allergic symptoms such as itching, sneezing, nasal congestion, and watery eyes. Antihistamines exert their effects by competitively binding to histamine receptors (specifically H1 receptors) on target cells, thereby preventing histamine from binding and exerting its physiological effects. By blocking histamine receptors, antihistamines inhibit the action of histamine, leading to the alleviation of allergy symptoms.

B) By reducing inflammation in the body:
While some medications, such as corticosteroids, exert anti-inflammatory effects by suppressing the immune response and inhibiting the production of inflammatory mediators, antihistamines primarily target histamine receptors and do not directly reduce inflammation. Although histamine release can contribute to inflammation, antihistamines mitigate allergic symptoms primarily by blocking the action of histamine rather than by directly reducing inflammation.

C) By increasing the production of histamine in the body:
This statement is inaccurate. Antihistamines do not increase the production of histamine; instead, they counteract the effects of histamine by blocking its activity at receptor sites. The primary mechanism of action of antihistamines involves blocking histamine receptors to prevent histamine from exerting its physiological effects.

D) By stimulating the immune system:
Antihistamines do not stimulate the immune system. Instead, they act as antagonists to histamine receptors, thereby inhibiting histamine-induced responses. While histamine is involved in immune responses and allergic reactions, antihistamines do not directly modulate immune function or stimulate immune activity. Their primary role is to alleviate allergy symptoms by blocking the effects of histamine."

A) Temperature and respiratory rate:
While monitoring temperature and respiratory rate are important aspects of a comprehensive assessment, they are not the priority assessments before administering metoprolol. Metoprolol is a beta-blocker primarily used to lower heart rate and blood pressure, so assessing the client's heart rate and blood pressure is more relevant.

B) Heart rate and blood pressure:
This is the correct answer. Before administering metoprolol, it is essential to assess the client's heart rate and blood pressure. Metoprolol is a beta-blocker medication that primarily affects heart rate and blood pressure. Monitoring these vital signs helps ensure that the medication is administered safely and effectively.

C) Level of consciousness and pain level:
Assessing the client's level of consciousness and pain level are important aspects of nursing care, but they are not the priority assessments before administering metoprolol. These assessments may be relevant depending on the client's overall condition and specific care needs, but they are not directly related to the action or side effects of metoprolol.

D) Oxygen saturation and respiratory rate:
Monitoring oxygen saturation and respiratory rate are important aspects of respiratory assessment, but they are not the priority assessments before administering metoprolol. While metoprolol can affect respiratory function as a potential side effect, its primary action is on heart rate and blood pressure. Therefore, assessing heart rate and blood pressure are more pertinent before administering this medication.