It would be incredibly easy to beat the cartels. Instead of fucking with the supply fuck with the demand. Seize a bunch of drugs then publically announce all drugs seized will be re-introduced into the drug supply via moles in the cartels. All drugs re-introduced will have horrific drugs added to them. List out the drugs and make it VERY CLEAR why you should not even think of risking it to get your fix.
1: EA-3167: Sends you to hell for about 2 weeks. Symptoms include panic attacks, complete paralysis, horrifying hallucinations, time perception changes. Everyone who has been exposed to it has become either a schizophrenic, killed themselves, or turned into a completely soulless Husk
2: Bromo Dragonfly: It makes all your limbs fall off
3: MPTP: It gives you Parkinsons, forever.
4: Phenazepam: Turns you into Ethan Ralph during a pillstream with the possibility of it looping forever.