Linezolid 600 mg IV once a day is ordered for a patient.

The linezolid is dissolved in 300 mL of NS and should infuse over 60 minutes.

Using an IV controller, how many milliliters per hour should the linezolid be infused?

St. John's wort (Hypericum perforatum) is a potent inducer of the cytochrome P450 enzyme system, specifically CYP3A4, in the liver. Warfarin is metabolized by the same enzyme system, primarily by CYP2C9. However, St. John's wort also induces other CYP enzymes that may indirectly affect warfarin metabolism. This enzyme induction accelerates the metabolism of warfarin, leading to subtherapeutic plasma concentrations. This reduces the anticoagulant effect of warfarin, increasing the risk of thrombus formation and thromboembolic events in the client.

Choice B rationale

This statement is factually incorrect. There is extensive scientific literature and numerous studies documenting the significant and clinically relevant drug interaction between St. John's wort and warfarin. The interaction is well-established, with multiple case reports and randomized controlled trials demonstrating that St. John's wort reduces the international normalized ratio (INR) in clients on warfarin therapy.

Choice C rationale

This response is non-therapeutic and dismissive of the client's question. It fails to provide the necessary health and safety information regarding a potentially dangerous drug interaction. A therapeutic communication approach requires the nurse to provide accurate, evidence-based information to empower the client to make informed health decisions.

Choice D rationale

This statement is factually incorrect and potentially life-threatening. St. John's wort can cause a dangerous drug-drug interaction with warfarin by reducing its therapeutic effect. Recommending this supplement to a client on warfarin could lead to a stroke, pulmonary embolism, or other life-threatening thromboembolic events due to the loss of adequate anticoagulation.

Choice A rationale

Scabies is caused by the mite Sarcoptes scabiei, which burrows into the stratum corneum of the epidermis to lay eggs. This infestation triggers a hypersensitivity reaction (type IV) in the host, resulting in intense pruritus (itching) due to inflammatory mediators. The itching is often worse at night because mite activity increases with warmth, and the host's body temperature rises under bed covers. The characteristic burrows and vesicles are commonly found in interdigital spaces and the axilla.

Choice B rationale

Pediculosis capitis, or head lice, is an infestation caused by the head louse, Pediculus humanus capitis. This parasite feeds on human blood from the scalp, leading to intense itching (pruritus) primarily on the head. Itching is a result of an allergic reaction to the louse saliva. Unlike scabies, pediculosis does not typically present with a rash in the interdigital spaces or axilla, but rather nits (eggs) and lice on the hair shaft and scalp.

Choice C rationale

Tinea corporis, commonly known as ringworm, is a superficial fungal infection of the skin caused by dermatophytes. It presents as an erythematous, circular, scaling patch with a raised border and central clearing, giving it the characteristic ring-like appearance. While it can cause itching (pruritus), it is a localized infection and does not typically manifest with generalized, nocturnal pruritus in the axilla and between the fingers like scabies.

Choice D rationale

Eczema, or atopic dermatitis, is a chronic inflammatory skin condition characterized by dry, erythematous, pruritic patches. While it causes intense itching, which can be worse at night, the distribution and presentation are different from scabies. Eczema typically affects the flexural areas (e.g., antecubital and popliteal fossae) in adolescents, and does not involve the characteristic burrows or interdigital rash associated with a mite infestation.