The healthcare provider orders Lasix 40 mg IV now. The concentration available is Lasix 20 mg/mL. How many mL will the patient receive?

Choice A reason: Beta 1-adrenergic drugs, like dobutamine, stimulate beta-1 receptors in the heart, increasing cyclic AMP and calcium influx, enhancing myocardial contractility. This increases stroke volume by strengthening heart contractions, directly improving cardiac output, making this the correct choice for the drug’s mechanism of action.

Choice B reason: Cardiac afterload is the resistance the heart pumps against. Beta 1-adrenergic drugs don’t directly reduce afterload; they increase contractility. Increasing afterload would decrease stroke volume, opposing the drug’s purpose, making this choice incorrect for the drug’s effect on stroke volume.

Choice C reason: Venous return affects preload, not directly influenced by beta 1-adrenergic drugs. These drugs enhance contractility, increasing stroke volume independently of venous return. While preload impacts output, it’s not the primary mechanism of beta-1 stimulation, making this choice incorrect.

Choice D reason: Cardiac preload is the initial stretch of the heart, influenced by venous return. Beta 1-adrenergic drugs increase contractility, not preload, to boost stroke volume. Preload changes are secondary and not the primary action of these drugs, making this choice incorrect.

Choice A reason: Long-term proton pump inhibitor (PPI) use has a weak, controversial association with gastric cancer due to hypergastrinemia, but evidence is inconclusive. In older patients, risks like osteoporosis and nutrient deficiencies are more established and immediate concerns, making this choice less consistently worrisome compared to others.

Choice B reason: PPIs reduce gastric acid, impairing calcium absorption, which increases osteoporosis risk in older patients. Chronic use is linked to decreased bone density and higher fracture risk, particularly in the elderly, due to disrupted mineral homeostasis, making this a significant and correct adverse effect to monitor.

Choice C reason: PPIs inhibit acid production, reducing absorption of vitamin B12, magnesium, and iron, leading to deficiencies in older patients. These can cause anemia, neurological issues, or hypomagnesemia, which are particularly concerning in the elderly due to comorbidities, making this a correct and critical adverse effect.

Choice D reason: Headaches are a possible PPI side effect but are less common and less severe in older patients compared to osteoporosis, nutrient deficiencies, or drug interactions. They don’t pose a significant long-term risk or require specific monitoring, making this choice incorrect for major concerns.

Choice E reason: PPIs interact with drugs like clopidogrel, reducing its efficacy by inhibiting CYP2C19, and affect absorption of drugs requiring acidic environments. In older patients with polypharmacy, these interactions increase risks of adverse outcomes, making this a significant and correct concern for PPI use.