[Buckeye McFrog]

Sounds like a lifelong junkie who probably does not have a usable vein left in his body.

[Boogieman]

Well, they can always inject straight into the heart. That’ll get it where it needs to go.

[nomad]

As a Freeper just suggested, subcutaneous injection. I`d do an intramuscular first with a high sedative dosage, then once asleep, simply use a large syringe with one concentrated, 10 times normal lethal cocktail of opiates and barbiturates, or two 5 times lethal, and do another intramuscular administration in the gluteal or thigh regions.