Is the profession of a medical sales representative permissible (halal) or forbidden (haram), taking into account the prevailing practices that include offering free samples, gifts, and financial compensation to doctors, in addition to the representative paying from their own money to sell the targeted quantity of medicines?

It is not permissible to offer gifts to doctors for the purpose of marketing medical products, as this may lead to Shari (Islamic legal) prohibitions, such as prescribing medication to someone who does not need it, or describing it with characteristics it does not possess, or opting not to prescribe a more beneficial medication to the patient because of a bribe. There is no objection to spending on drug promotion from your own money or the company's money, provided the person in charge is aware if it is from the company's funds.