Adsorption and interaction mechanisms of fullerene-based complex systems for possible drug delivery vehicles have been at the center of increasing attention. In the scope of this work, the interaction mechanism between an important antiviral drug favipiravir and silicon-doped/undoped C60 fullerenes have been investigated using density functional theory (DFT). Calculations were carried out in both gas phase and water media to see the possible solvent effects. The effect of adsorption of the favipiravir on the SiC59 fullerene system and the nature of interaction were examined by analyzing the band shifts in the carbonyl stretching vibrations and natural bond orbital (NBO) properties of the examined complexes. Some important structural and electronic properties were reported and discussed as well. It was observed that doping the C60 fullerene nanocages with silicon atom enhanced the adsorption mechanism and calculations performed in water media gave rise to more stable complexes for silicon-doped systems compared to the results obtained for the gas phase. Results and parameters found in the present search reveal further insights into the drug delivery systems.