A nurse is reviewing the concept of therapeutic index for medications. Which of the following statements best describes a drug with a narrow therapeutic index?

A. "The IV heparin increases the effects of the warfarin and decreases the length of your hospital stay.": Heparin does not enhance the effect of warfarin directly. Their mechanisms of action are different, and warfarin’s effect is delayed. Heparin is used to maintain anticoagulation until warfarin becomes effective.
B. "Both heparin and warfarin work together to dissolve the clots.": Neither heparin nor warfarin dissolves existing clots; they prevent further clot formation and allow the body’s natural fibrinolytic system to break down clots. This statement misrepresents their action.
C. "Warfarin takes several days to work, so the IV heparin will be used until the warfarin reaches a therapeutic level.": Warfarin requires 3–5 days to reach therapeutic INR levels due to its action on vitamin K-dependent clotting factors. Heparin provides immediate anticoagulation, which is why it is continued until warfarin is therapeutic.
D. "I will call the provider to get a prescription for discontinuing the IV heparin today.": Discontinuing heparin too soon places the patient at risk for clot progression or embolization, as warfarin will not yet be therapeutic. The nurse should understand and educate the patient about the rationale for overlap.

A. Intramuscular Phenobarbital: While effective as an anticonvulsant, phenobarbital has a slower onset of action and is not the preferred first-line treatment for acute seizures. It is more commonly used in refractory cases or for long-term seizure control.
B. Intravenous Lorazepam: Lorazepam is a benzodiazepine and the first-line treatment for active seizures, especially status epilepticus. Given IV, it acts quickly by enhancing GABA activity, which calms neuronal excitability and stops seizure activity efficiently.
C. Oral Phenytoin: Phenytoin is used for long-term seizure prevention but is not effective for terminating ongoing seizures due to its slow onset when taken orally. It may be used after benzodiazepines to prevent seizure recurrence but not as the initial agent.
D. Subcutaneous Sumatriptan: Sumatriptan is used for treating acute migraines and has no role in managing seizures. It acts on serotonin receptors to relieve migraine symptoms, not to control abnormal neuronal discharges.