Continuous infusion, as one of the most effective methods of delivering pharmaceuticals to patients, uses infusion pumps to which a syringe and infusion drains are connected. Photosensitive drugs that require UV-VIS protection are delivered to patients with special infusion sets that reduce harmful radiation. However, these drains have different transparencies, which can affect the success of therapy. This study investigated the optical properties of two types of drains used for infusion therapy of photosensitive drugs. UV-VIS spectroscopy studies were carried out, allowing determination of the absorbance values and absorption coefficient of the two types of drains based on the results obtained. The spectrum of their transmittance was also analyzed. The chemical composition of the samples was analyzed using FTIR-ATR spectroscopy. Furthermore, the roughness and wettability parameters of the drains were determined, which affect not only the kinematics of drug flow in the drains but also the way in which light is transmitted. The results of the study can be used to propose a solution to eliminate the problem of loss of properties of the photosensitive drug in drains, in contact with light. By selecting the appropriate drain thickness, it is possible to reduce the transmission of radiation in the UV-VIS range through the drain.