Final answer:
4)Xalatan is the medication among the listed options that requires refrigeration prior to its first use. It is important to follow the specific storage instructions provided with each medication.
Step-by-step explanation:
The medication among the options provided that requires refrigeration is Xalatan. Xalatan (latanoprost) is a prostaglandin eye drop used to treat glaucoma which must be stored in a refrigerator before opening and can be stored at room temperature thereafter for up to 6 weeks. The other medications listed, such as Ibuprofen liquid, Accutane, and Tretinoin Cream usually do not require refrigeration but should be kept at room temperature away from direct light and moisture. Always refer to the specific storage instructions on the medication's label or packaging for the most accurate information.