Is it obligatory to stop fasting and praying upon seeing a brownish fluid accompanied by menstrual pains, before seeing clear menstrual blood, given that medication causes a delay in menstruation?

In summary, yellowness (ṣufrah) and brownish discharge (kudrah) are not considered menstruation unless they occur during the habitual period or are connected to blood. This is the view of the Hanbalis. If a woman sees them during her habitual period, they are considered menstruation, and she should refrain from fasting and prayer, make up any obligatory fasts, and perform ghusl (ritual bath) after their cessation. However, outside of the habitual period, she is only required to perform wudu' (ablution) due to the emission of these discharges. If their emission is continuous, she should perform wudu' for each prayer after its time has entered, take precautions, and pray like a woman experiencing istihada (non-menstrual bleeding).