A 22-year-old man with seasonal allergic rhinitis takes an antihistamine for relief of symptoms. It is successful for him over 90% of the time. Histamine is a natural amine formed by the decarboxylation of which of the following amino acids?

Correct Answer: C

Rationale: Histamine, key in allergies, is derived from histidine via decarboxylation. L-arginine , Lysine , and Tyrosine (E) form other amines. Heparin is a glycosaminoglycan. Histidine's conversion drives allergic responses, blocked by antihistamines.

Correct Answer: A

Rationale: Protamine sulfate is the antidote for Heparin. Heparin is an anticoagulant medication that works by inhibiting the clotting factors in the blood. In cases of Heparin overdose or when there is a need to reverse its anticoagulant effects quickly, protamine sulfate can be administered. Protamine sulfate binds to Heparin and neutralizes its anticoagulant effects, making it an effective antidote. It is important to administer the antidote under the guidance of a healthcare professional to prevent any adverse reactions.

Correct Answer: A

Rationale: HRT, often involving estrogen, increases thrombophlebitis risk due to enhanced clotting factors. Calf pain signals possible deep vein thrombosis (DVT), a life-threatening side effect requiring immediate assessment, as it could lead to pulmonary embolism. Decreased libido , low-back pain , and fatigue may occur with HRT but are less urgent and not specific to its most dangerous complications. The nurse prioritizes calf pain due to its association with thromboembolism, a well-documented HRT risk, especially in smokers or those with vascular issues, making choice A the critical focus for safety.

Correct Answer: A

Rationale: Allopurinol reduces uric acid production, treating gout by inhibiting xanthine oxidase. Monitoring serum uric acid tracks efficacy, ensuring levels drop (normal: 3.5-7.2 mg/dL) to prevent flares. BUN reflects kidney function, relevant but secondary unless damage exists. White blood cells and platelets aren't directly affected unless hypersensitivity occurs (rare). Uric acid is the therapeutic target, aligning with allopurinol's mechanism, critical in gout where hyperuricemia drives symptoms. Regular checks confirm treatment success, guiding dose adjustments, making A the key value to monitor.

Correct Answer: D

Rationale: Calcium absorption in the small intestine relies heavily on vitamin D, which enhances the process by increasing the expression of calcium-binding proteins and improving gut uptake efficiency. Without adequate vitamin D, calcium absorption drops significantly, leading to potential bone health issues like osteoporosis or osteomalacia. Intrinsic factor, produced in the stomach, is critical for vitamin B12 absorption, not calcium, as it binds B12 for uptake in the ileum. Coenzymes, while involved in metabolic reactions, don't directly facilitate calcium absorption; their role is broader and unrelated to this specific process. Phosphorus, an abundant mineral, works with calcium in bone formation but doesn't enhance its absorption-in fact, excessive phosphorus can compete with calcium. Vitamin D's active form, calcitriol, regulates calcium levels by promoting its transport across intestinal cells, making it indispensable for maintaining skeletal integrity. This mechanism underscores why vitamin D deficiency impairs calcium utilization, distinguishing it from the other options, which lack a direct link to absorption efficiency.

Correct Answer: C

Rationale: Histamine, key in allergies, is derived from histidine via decarboxylation. L-arginine , Lysine , and Tyrosine (E) form other amines. Heparin is a glycosaminoglycan. Histidine's conversion drives allergic responses, blocked by antihistamines.

Correct Answer: C

Rationale: Protamine sulfate is a medication that can antagonize the anticoagulant effects of heparin. Heparin works by binding to antithrombin III to enhance its activity, which leads to the inhibition of factor Xa and thrombin. Protamine sulfate, a positively charged molecule, binds to heparin to form a stable complex, neutralizing the anticoagulant effects of heparin. This makes protamine sulfate a useful antidote for heparin overdose or in situations where rapid reversal of heparin is necessary to reduce the risk of bleeding complications. The other options listed - acetylcysteine, naloxone, warfarin sodium, and phenindione - do not have a direct antagonistic effect on the anticoagulant effects of heparin.

Correct Answer: A

Rationale: Etanercept is administered via injection, and some formulations may contain latex in the packaging or delivery system. Assessing for a latex allergy is crucial to prevent allergic reactions. While vaccinations and travel plans are important considerations, they are not as critical as ensuring the client's safety regarding potential allergens. Avoiding people who recently received etanercept is not a standard precaution.

Correct Answer: B

Rationale: Protamine sulfate is commonly used as an antidote for heparin overdose. Heparin is an anticoagulant medication given to prevent blood clots, but in cases of excessive bleeding or overdose, protamine sulfate can be administered to counteract its effects. Therefore, it is important to be aware that protamine sulfate can negate the therapeutic effect of heparin.