This thesis presents the case of a patient with castration-resistant non-metastatic prostate cancer. The patient approached the Pharmacotherapy Consultation (Farmakoterapijsko savjetovalište) with a primary therapeutic problem of joint pain, which he suspected was a side effect of estramustine, a drug prescribed for cancer therapy. During consultations carried out in the center, in agreement with a family medicine doctor and an oncology specialist, the drug was replaced with apalutamide, a drug indicated for castration-resistant non-metastatic prostate cancer. Apalutamide belongs to the group of antiandrogens (hormonal therapy) and was put on the Croatian market in 2020. During apalutamide therapy, his PSA and testosterone values were well regulated, but he developed a side effect of hypertension refractory to all therapeutic combinations of antihypertensive drugs. After different combinations of drugs for the treatment of hypertension were tried through nine consultations over a period of two years, and his blood pressure was not successfully regulated despite all the combinations, it was concluded that it was resistant hypertension. Therefore, when darolutamide, also a drug with an antiandrogenic effect, appeared on the market, apalutamide was replaced by darolutamide in the patient due to the lower likelihood of developing hypertension as a side effect. The aim of this thesis was to present in detail the case of one patient with non-metastatic prostate cancer in whom the side effect of resistant hypertension developed after the use of a new drug for the treatment of prostate cancer - apalutamide. Given that the goal was a detailed presentation of the consultations that led to the regulation of blood pressure, the research was conducted using the case study method.