There are accidents that may involve dogs eating or taking in illegal substances like heroin or cocaine. The first one is capable of killing a dog with just a small amount, the second can keep it high for a long time and permanently damage its brain. These accidents do not usually happen to dogs without their being involved in work with drugs.
The K9 units of this country are considered the best trained and prepared for any contingencies in police work. Many canines are in the service for police departments, the FBI and related agencies and their handlers are often trained for canine opioid overdose. This is an emergency response process which requires almost instant use of an antidote.
The most commonly effective is Naloxone, which might be taken along with a dose of mild sedatives. The dogs are not equipped to fight a high, much less an overdose, and there is no given amount level that does not affect them adversely. In cases involving OD of, say, heroin, the canines ingest the stuff accidentally.
There were earlier times in K9 processes when the handlers had no safety measures when it comes to accidental opioid ingestion. The dogs sniff out contraband and these might not be well hidden. The packets are simply plastics and the animals bite and then lick what they have sniffed, which is natural for them.
Their training does not include response or tolerance to drugs, and canine systems are more sensitive and weaker compared to humans on this level. Some animals were killed outright, valuable and highly trained though they were, there was no response procedure that might have helped. Today, there are procedures in place and canines will not usually come in contact with contraband.
All they are trained to do is sniff the stuff out, then human personnel can then work to get at it. The training now makes them stop at smelling but they are required to sit and stand down when the contraband is being handled. These are dedicated workers who require less of what human experts can have here.
So they are given whatever protection is possible for them in the line of duty. The response times today are a matter of seconds for such emergencies. In other kinds of accidents, usually those who are use these drugs themselves and keep pets may cause such accidental ingestion and will likely kill their pets.
The overdose is lethal, and again there is no minimum dosage level in which the dogs are considered safe. Some can survive but will have permanent damage to their systems. Also, a sedative shot is needed because the trained canines are not really able to handle adverse drug effects. They are sensitive this way, and need to be calm to take the antidote.
Handlers are also trained to respond immediately. The process is now part of the manual of instruction for police training academies and other establishments using the services of another specie. The dogs remain the best workers in this business and are appreciated as such.