The healthcare provider orders Benadryl 40 mg IM now. The available concentration is 25 mg/mL. How many mL will the patient receive?

Choice A reason: Taking antihistamines only with symptoms may reduce side effects but provides inconsistent relief, as histamine levels fluctuate. Daily use during allergy seasons prevents symptom onset, offering better control, especially for second-generation antihistamines with longer action, making this choice less effective.

Choice B reason: First-generation antihistamines (e.g., diphenhydramine) are sedating and have more side effects than second-generation (e.g., loratadine), which are equally effective for allergies but less sedating. Claiming first-generation are more effective is incorrect, as second-generation are preferred, making this choice inaccurate.

Choice C reason: Anticholinergic effects (e.g., dry mouth) are more common with first-generation antihistamines (e.g., diphenhydramine) due to non-selective receptor binding. Second-generation antihistamines (e.g., cetirizine) are more selective for H1 receptors, reducing these effects, making this choice incorrect and opposite to pharmacological profiles.

Choice D reason: Daily oral antihistamines, especially second-generation (e.g., loratadine), during allergy seasons maintain steady histamine receptor blockade, preventing symptoms like sneezing and itching. This maximizes efficacy and improves quality of life, aligning with guidelines for seasonal allergies, making this the correct nurse response.

Choice A reason: Patient weight: 198 lbs ÷ 2.2 = 90 kg. Dose: 1 mg/kg × 90 kg = 90 mg. Volume: 90 mg ÷ (30 mg/0.3 mL) = 90 × 0.3/30 = 0.9 mL. This delivers the correct anticoagulant dose for conditions like DVT, making it the accurate choice.

Choice B reason: For 90 kg (198 lbs ÷ 2.2), the dose is 90 mg. Volume: 90 mg ÷ (30 mg/0.3 mL) = 0.9 mL. Choice B (1.2 mL) delivers 120 mg (1.2 × 30/0.3), overdosing Lovenox, increasing bleeding risk, making it incorrect.

Choice C reason: The correct volume for 90 mg is 0.9 mL (90 ÷ 30 mg/0.3 mL). Choice C (0.6 mL) delivers 60 mg (0.6 × 30/0.3), underdosing Lovenox, reducing anticoagulant efficacy, which could fail to prevent thrombosis, making this choice incorrect.

Choice D reason: For 90 mg, the volume is 0.9 mL. Choice D (0.3 mL) delivers 30 mg (0.3 × 30/0.3), significantly underdosing Lovenox for a 90 kg patient, risking inadequate anticoagulation and thrombotic events, making this choice incorrect.