A patient with a history of anxiety disorder is prescribed lorazepam at a dosage of 1 mg to be administered every 8 hours as needed. If the patient has already received 2 doses today, what is the maximum additional dosage they can safely receive within the same day?

Choice A reason: A 3 mg additional dose would exceed the prescribed limit. The prescription allows for 1 mg every 8 hours as needed, up to a maximum of 3 mg in a 24-hour period (one dose every 8 hours). Since the patient has already received 2 mg (two 1 mg doses), an additional 3 mg would result in a total of 5 mg, which is unsafe and exceeds the prescribed daily limit. Choice B reason: A 2 mg additional dose would also exceed the prescribed limit. With 2 mg already taken, an additional 2 mg would total 4 mg in a day, surpassing the maximum of 3 mg allowed by the prescription (1 mg every 8 hours, up to three doses). Choice C reason: The patient has already received 2 mg (two 1 mg doses) today. The prescription allows for 1 mg every 8 hours as needed, which permits a maximum of 3 mg in 24 hours. With two doses already administered, only one additional 1 mg dose is safe, but none of the options list 1 mg. Therefore, 0 mg is the correct answer, as no additional dose beyond the remaining 1 mg is permissible among the given choices.