At best the drug marketing departments take them out to a meal/lunch/dinner, but even that is rare.
Any transaction over $10 is also tracked in a database (for instance if they do take a doctor out to dinner to spend time educating the doctor on the drug, of which the doctor is under no obligation)
D.A.B. V Brown and US vs Brown are perfect examples of doctors being sued when they do this illegal activity.
Also every state has laws against pharmaceutical kickbacks.
Doctors can be paid to do speaking/educational events and for travel for these events, but they are not allowed to take actual kickbacks for prescribing drugs.
Doctors can lose their medical license if proven that they received a kickback and also thrown in jail.
Kickbacks fall under malpractice and negligence.
Those who spout the fake news that doctors receive kickbacks clearly haven’t done even the most basic of research on the topic.