Deficiencies in cyanocobalamin (B12) can result in

Correct Answer: B

Rationale: Cyanocobalamin, or vitamin B12, is essential for red blood cell production and neurological function, and its deficiency directly leads to pernicious anemia, a condition characterized by large, immature red blood cells due to impaired DNA synthesis. This occurs because B12 is crucial for folate metabolism and erythropoiesis, and without it, anemia develops, often accompanied by neurological symptoms like numbness or tingling. Pellagra, however, results from niacin (vitamin B3) deficiency, manifesting as dermatitis, diarrhea, and dementia-unrelated to B12's role. Rickets stems from vitamin D deficiency, causing bone deformities due to poor calcium absorption, not a B12 issue. Scurvy arises from vitamin C deficiency, leading to collagen breakdown and symptoms like bleeding gums, distinct from B12's hematological effects. Pernicious anemia stands out as the correct outcome because B12 deficiency disrupts bone marrow function, and it often requires pharmacotherapy, such as B12 injections, especially if absorption is impaired (e.g., due to lack of intrinsic factor). This specificity eliminates other conditions, highlighting B12's unique role in blood and nerve health.

Correct Answer: D

Rationale: Intranasal corticosteroids (e.g., fluticasone) can cause burning and nosebleeds due to mucosal drying . They're preventive, not symptom-driven (choice B is wrong), and dosing is fixed, not squeeze-dependent . Choice D educates on a common, manageable side effect, ensuring client awareness and compliance.

Correct Answer: B

Rationale: Heparin is an anticoagulant medication used to prevent blood clots. If a patient on heparin therapy experiences excessive bleeding or needs to quickly reverse the anticoagulant effects of heparin, the antidote is protamine sulfate. Protamine sulfate works by neutralizing the effects of heparin by forming a complex with it. It is important for healthcare providers to have protamine sulfate readily available when managing patients on heparin therapy to effectively reverse its anticoagulant effects in emergency situations.

Correct Answer: D

Rationale: Histamine is a biogenic amine that acts as a neurotransmitter in the body. It is known to have several pharmacologic properties, such as the ability to reduce gastric secretion (Choice A), relaxation of vascular smooth muscle (Choice B), contraction of bronchi (Choice C), and production of pain and itch (Choice E). However, histamine does not have a direct effect on free nerve endings. Its effects on pain and itch are mediated through activation of specific histamine receptors on nerve cells and not through direct action on free nerve endings.

Correct Answer: C

Rationale: Ionized drugs cross renal tubular membranes poorly, staying in urine for excretion, unlike non-ionized or lipid-soluble drugs reabsorbed easily. Volatile drugs (e.g., anesthetics) excrete via lungs, not kidneys. Ionization traps drugs, a pharmacokinetic excretion key.