Daily Archives: November 25, 2009

Cocaine and Pepper Spray: A Lethal Combination?

So you’re out for an evening of doing fuzzy rails with your buddies and on the way home you’re pulled over by the police because you’re having a little problem staying between the lines — pun intended. Of course the officer will ask for identification but your coked-up brain will misread this as a threat so you go off on the officer. A word of warning — this is never a good thing to do to someone who carries a gun, or in this case, pepper spray. So the cop, rather than shooting you, sprays you with pepper spray and you go down never to rise again. Then people stand around a hole in the ground and talk about what a good guy you were and what a jerk the cop was for killing you with pepper spray. Could happen.

Was it the combination of cocaine and pepper spray that did you in? Maybe, maybe not. Some new research suggests the answer is yes but, as usual, the devil is in the details.

In a recent issue of Forensic Toxicology, there is a report that suggests the mixture of cocaine and pepper spray could indeed be deadly. The study seems to revolve around two sets of data.

Mice were injected with cocaine and capsaicin, the chemical that gives peppers their kick. It’s also what makes pepper spray such an unpleasant chemical. They initially used a dose of cocaine that killed only a few of the mice and then found that when the same amount was injected along with capsaicin approximately 50% of the mice died. Then they injected the mice with an amount of cocaine that would kill approximately 50% of them. In medicine this dose is called the LD50 (Lethal Dose 50%) or the dose of any drug that would be expected to kill 50% of those who received it. When capsaicin was added to this amount the mortality rate approached 90%. From this one could construe that the combination of cocaine and pepper spray interact in some way and become a lethal combination and this could explain pepper spray deaths in humans.

Not so fast. The problem here is that these are mice and not humans. Though a great deal of medical research begins with mice it must eventually evolve into human trials before any real conclusions can be drawn. Studies done on mice are merely suggestions. Also these drugs were injected, which changes everything. Snorting cocaine is not the same as injecting it. Close but not quite. Pepper spray to the face may be a more local reaction and it may not be absorbed into the bloodstream at all. Injected capsaicin would indeed reach the bloodstream and just might be more toxic or might undergo some chemical alteration that is not present when it merely contacts the face and eyes. So this is the classic apples and oranges and little can be gleaned from this study that would help us determine if this combination is lethal to humans or not.

The investigators then looked at 26 autopsy reports between 1993 and 1995 on people who died shortly after receiving a spray of pepper. They found that 19 of them had evidence of some form of “psychostimulant,” and nine of these indeed did have cocaine in their system. This again would make someone consider that cocaine, or a similar chemical, within the victim interacted in some way with the capsaicin and this combination caused the deaths.

Again, not so fast. First of all, this is a very small study, involving only 26 people, and therefore any statistical analysis is fraught with inaccuracies. Sort of like winning 19 of your first 26 blackjack hands in Vegas and thinking this means you’ll win all night long. Never happens. Had this been a study of several hundred, or better several thousand, people then we might be able to draw some statistical conclusions.

The other part of the equation is why such a combination would prove lethal. What about cocaine and capsaicin make them a dangerous combo?

I doubt seriously that there is an actual chemical reaction between the two though this is possible. More likely, if there is an increased incidence of death with this combination, it is due to how each of these chemicals work independently. Cocaine is a stimulant. It stimulates the brain and the cardiovascular system. It causes euphoria, which is the desired effect, but can also cause confusion, disorientation, seizures, massive elevation of the blood pressure with a resulting stroke, and spasm of the coronary arteries which can lead to a heart attack (myocardial infarction) or a cardiac arrhythmia — a change in the cardiac rhythm which is potentially lethal.

There’s another drug that lives in our body that will also do most of the same things. This chemical is epinephrine or adrenaline. It resides in our adrenal glands, which sit just on top of the kidneys on either side. This is the fight or flight chemical. When someone says boo or the bad guys are chasing you down a dark alley or a bear crashes into your living room, this is the drug that will save your life. It revs up the heart rate and blood pressure and the reflexes and the muscular strength and the speed of muscular contraction and allows you to fight or run more effectively. But when present in excess, epinephrine can also cause coronary spasm with a heart attack, elevated blood pressure with a stroke, and dangerous cardiac arrhythmias.

Pepper spray is a very painful product to have sprayed in your face. The reaction to this sudden pain and burning of the eyes and throat is a fight or flight response. Epinephrine is released by the adrenal glands in massive quantities and, in a situation where there is already cocaine in the system, it could easily cause dangerous arrhythmias, heart attacks, or strokes. The combination of cocaine and epinephrine is known to be potentially deadly.

I would suspect that if this combination does indeed prove to be lethal that this is the mechanism by which it occurs. The danger is not from the cocaine and the pepper spray, at least not directly, but rather from the combination of cocaine and the epinephrine that is released due to the pain of the capsaicin. The devil is in the details.

But from a practical point of view, dead is dead and the mechanism is more or less irrelevant. Very interesting and I hope there is further research in this arena.

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