This is the 13406th most frequent Polish word.
pacjentowi
"Pacjentowi" means "to the patient" in English.
In this sentence, "pacjentowi" is the dative form of "pacjent" used as the indirect object receiving the medicine.
Lekarz podał lek pacjentowi.
The doctor administered medicine to the patient.
Here, "pacjentowi" again serves as the indirect object indicating the beneficiary of the action.
Drzwi otworzono pacjentowi.
The door was opened for the patient.
"Pacjentowi" in this case is the indirect object who is receiving the new recommendations.