Mainlining is seen in which of the following drug abuse in which the patient will inject drug into main veins

Mainlining(SHIFT from peripheral to central vein injections) and skin popping(injecting SC) are seen in abuse of opioids opiod use is not a medical emergency like alcohol but opiod withdrawl is one of the ourite questions for examiners the famous quote that is used for describing opiod withdrawl is ALL ORIFICES BLEED WITH PUPILLARY DIALATION you need to inculcate the image of opiod withdrawl that is given in your mind to answer case scenario related questions. Ref: Essentials of postgraduate psychiatry By JN Vyas 1st ed Pg 338