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: For 40 mg at 25 mg/mL: 40 ÷ 25 = 1.6 mL. Choice A (0.6 mL) delivers 15 mg (0.6 × 25), underdosing Benadryl, which could fail to relieve allergic symptoms or sedation needs, making this choice incorrect for the prescribed dose. Choice B reason: Calculating 40 mg ÷ 25 mg/mL = 1.6 mL accurately delivers the ordered 40 mg of Benadryl (diphenhydramine) for allergy or sedation. This ensures therapeutic efficacy without overdose, aligning with safe administration for intramuscular delivery, making this the correct choice. Choice C reason: For 40 mg, the volume is 40 ÷ 25 = 1.6 mL. Choice C (2 mL) delivers 50 mg (2 × 25), overdosing Benadryl, risking excessive sedation or anticholinergic effects like dry mouth or confusion, making this choice incorrect and potentially unsafe. Choice D reason: The correct volume is 1.6 mL (40 ÷ 25). Choice D (1 mL) delivers 25 mg (1 × 25), underdosing Benadryl, which may not achieve therapeutic effects for allergies or sedation, making this choice inadequate for the prescribed dose.