The population growth and global development are resulting in an increase in pollution of the water environment. Pharmaceutical micropollutants which are detected in waste water and drinking water present a great jeopardy. Among them is memantine, a medicine used for easing the symptoms of Alzheimer's disease. Memantine is virtually unmodified in the human organism thereby being released unchanged into the environment. It is very environmentally stable and resistant to photolysis caused by direct solar irradiation. Memantine is difficult to detect and remove from the water so it is necessary to develop new methods. This study questions the efficiency of advanced oxidation processes, specifically photocatalytical processes in memantine removal with simulated Sun irradiation using a TiO2-SnS2 photocatalyst and H2O2 as oxidant. With the help of statistical experimental planning the response surface methodology, the influences of pH and H2O2 were investigated. The value of pH is not a significant parameter in the process and does not have a significant influence on the action of H2O2 in the photocatalytic degradation of memantine by TiO2-SnS2 photocatalyst, while the interaction parameter for pH and H2O2 has a significant influence on the action of SnS2 in the process. The adsorption of memantine on the surface of photocatalyst has not been observed. The largest photocatalytic activity has been achieved with the smallest percentage of SnS2 in the composite. The optimal process conditions are pH = 6.74, [H2O2] = 4.33 mM and w(SnS2) = 5%, achieving 37% of memantine degradation after 60 minutes of solar photocatalytic treatment.