A nurse is reviewing pharmacokinetic principles. Which of the following factors most significantly affects the distribution of drugs in the body?

A. Beta-blockers like metoprolol can mask the signs of hypoglycemia: Metoprolol can blunt adrenergic symptoms such as tachycardia and tremors, which are key warning signs of hypoglycemia. This is especially concerning in diabetic patients who rely on these symptoms for early detection of low blood glucose.
B. It is safe to take additional doses of Sertraline if the patient feels like their symptoms are worsening: Sertraline, a selective serotonin reuptake inhibitor (SSRI), must be taken exactly as prescribed. Taking extra doses increases the risk of serotonin syndrome, which can be life-threatening and requires medical supervision for dosage adjustments.
C. The patient should be monitored for orthostatic hypotension: Older adults taking medications like metoprolol and triazolam are at increased risk for orthostatic hypotension due to vasodilation and CNS depression. Monitoring helps prevent falls and syncope, especially when changing positions.
D. Oxycodone can be used long-term without risk of physical dependence: Oxycodone is an opioid analgesic and carries a high risk of tolerance, physical dependence, and addiction when used long-term. Even when used appropriately, patients can develop dependence, necessitating careful monitoring.
E. The combination of triazolam and oxycodone increases the risk of respiratory depression: Both drugs are CNS depressants, and their combination can have a synergistic effect on respiratory centers in the brain. This raises the risk of severe respiratory depression, particularly in older adults or those with underlying respiratory conditions.

A. "The oral medication you will take after this IV will dissolve the clot.": Oral anticoagulants like warfarin also do not dissolve existing clots. They work similarly to heparin by preventing the formation of new clots and allowing the body’s natural fibrinolytic mechanisms to break down existing ones over time.
B. "Heparin does not dissolve clots. It stops new clots from forming.": This is the most accurate explanation. Heparin is an anticoagulant that enhances antithrombin activity, inhibiting clotting factors and preventing clot propagation, but it does not actively lyse or dissolve clots.
C. "It usually takes heparin at least 2 to 3 days to reach a therapeutic blood level.": Heparin given intravenously has a rapid onset of action, often within minutes. Therapeutic levels are typically reached quickly with continuous infusion, so this statement is inaccurate.
D. "A pharmacist is the person to answer that question.": While pharmacists are valuable for drug-related questions, nurses are expected to provide basic patient education regarding medications, including mechanism of action, especially during bedside care.