This work aimed to analyze the presence of four common molecules (diclofenac, dipyrone, ibuprofen, and paracetamol) in the Ipojuca River, in the stretch of Caruaru municipality (Brazil), and in a wastewater treatment plant that discharges treated water to the river. Collections were conducted for three months at each point during April, May, and June. The samples were collected in three repetitions (sample, replica, and triplicate). Through Pearson’s correlation, the correlation between ibuprofen and diclofenac concentration and rainfall in the region was also verified. These drugs were detected in 100% of the samples, with concentrations between 7.4–548.2 and 81.8–231.8 μg.L-1, respectively. Paracetamol and dipyrone were not detected. The observed high concentrations are due to the high consumption of drugs and the low rate of sewage collection in the municipality. Both analyzed drugs — ibuprofen and diclofenac — had insignificant correlation results with rainfall (-0.022 and -0.071, respectively). Regarding the drugs in the WWTP, the treatment consisting of anaerobic followed by aerated lagoons showed efficiency ranging from 35.9 to 93.6% in the removal of diclofenac. The removal of ibuprofen was higher in April (86.6%), but in the other two months, it did not prove to be efficient, evidencing the need to implement more adapted technologies in the removal of drugs combined with the network expansion for sewage collection in the region. A study with longer time monitoring is needed to understand the rainfall effect on drug concentration in the river.