Is it obligatory to repeat the prayer after waking up from a wet dream, with the presence of secretions resulting from the dissolution of a vaginal medication, along with doubt about their mixing with semen?

Ghusl is only obligatory when one is certain of seminal emission. Doubt about it does not necessitate Ghusl. What is certain is the discharge of the medication, and anything beyond that is doubtful. The default is that no additional substance mixed with this medication has been discharged. Doubt concerning ritual impurity after being certain of ritual purity does not invalidate it. Therefore, performing Wudu is sufficient as long as you are not certain of seminal emission.