As I write about murder, I often have to ask myself this question: What is the perfect drug to use as a murder weapon?
There are a number of possibilities, but most have flaws that make them less 
than perfect. So let me narrow down the field. Anything that would leave behind telltale trace should be eliminated right away. Agreed?
For instance, a strong tranquilizer like Valium would leave lots of evidence in the blood. We need to find a drug that either leaves no metabolite trace or one that is indigenous to the body.
Let’s discuss that first requirement: leaving no metabolite trace. What is a metabolite, anyway? By definition, it’s a byproduct of the body’s metabolism. It’s 
what’s left after the body breaks down a substance into either small parts or changes the substance (drug) into other chemicals. For example, when we eat an egg (made up of protein, carbs and fat), our bodies break it down into its components that can then be used for fuel and the rest is eliminated.
The same thing happens with drugs. They’re broken down into metabolites (the byproducts) and they circulate in the bloodstream until we eliminate them (usually through the kidneys). So, what drug leaves no metabolite trace? The simple answer is NONE.
That leaves us with a second requirement: a drug that may leave behind metabolites, but only ones that are normal to the body. There are several possibilities, but two come to mind that are excellent.
The first is succinylcholine (SUX for short). It’s a neuromuscular paralytic drug. In short, it causes ALL the muscles of the body to be paralyzed. They simply stop
functioning, including those used for breathing. So without medical help, a person given a dose of SUX will stop breathing and asphyxiate. That happens in a matter of seconds and certainly less than a minute after a person is injected with the drug.
That’s why it’s used in anesthesia. It helps doctors get those breathing tubes down the throat easier during surgeries. It’s an effective drug and fast acting, but it’s an agonizing death since the person remains wide awake while the drug is doing its job paralyzing all the muscles of the body.
It’s a perfect murder weapon because it metabolizes (gets broken down by the body) almost immediately into the byproducts succinic acid and choline, both of which are normal to the body.
And at autopsy, minutely elevated levels of these chemicals are the only evidence of the crime, and toxicologists and medical examiners would easily overlook the slightly abnormal blood chemistry. It would be a difficult to prove murder without corroborating evidence linking the actual injection to the perpetrator.
The second drug that could make the perfect murder weapon is potassium chloride. This drug specifically is used to treat patients with extremely low levels 
of potassium. And, when given, the drug simply is metabolized into the components potassium and chloride, both of which are normally in the body.
An overdose of injected potassium causes severe heart arrhythmias and mimics a heart attack. In a matter of minutes, the heart spasms and then simply stops functioning in what’s called SCD (sudden cardiac death).
But what about those pesky elevated blood levels of potassium? Not a problem! Whenever any muscle tissue is damaged (and the heart is muscle tissue), unusually large amounts of potassium are released into our blood. So a medical examiner would likely list the cause of death as a fatal heart attack.
So today you have a BONUS. Not one but two great drug choices to write about the perfect murder. Is it any wonder that the prison system uses both of these drugs in the trio cocktail mix used in lethal injections? Happy writing as you plot the next perfect crime.
Thoughts? Comments? I’d love to hear them.
Prescription For Murder 
Jim,
I think that anybody who follows your blog and finds themselves even on the periphery of a suspicious death is in for an interesting time.
Keep up the good writing.
Walt.
Pingback: My brother Jim Murray with – well, maybe an idea for a great book – the drug to use to commit murder! « Thomas Rydder
Thanks, Thomas, for the repost!! Always appreciated!
I know the perfect potion that kills in a few days leaving no trace behind – but a) it’s not a drug, b) is available for a few dollars in lots of outlets and c) it would be irresponsible of me to say what it is in an open forum.
Hmmm!??? Now I’m curious! Send me an e-mail, jumeirajames, with what you’re thinking? james@jamesjmurray.com – thanks!
Okay, you’ve got me interested. If you don’t mind, email me. jim@giacomogiammatteo.com
Hi jumeirajames,
I just came across your comment regarding the perfect potion. We are working on a movie script for a murder mystery and would be very interested to hear your thoughts. Please write me at: rosenberg.jeanee@gmail.com
best regards,
Jeanee
what is it
You’ve piqued my curiosity too. Please write back directly with details. Thanks.
Better yet, I’ll start posting in my next few blogs links to my books (one in particular is being re-published and it’s sequel will come out in the Fall). Both deal with “the perfect murder weapon” scenarios. Stay tuned and thanks for your interest in my blogs. All the best!
We are having an Ultimate murder mystery weekend for groups of detectives, be interested to hear what this is to see how good they are 🙂
We are having the Ultimate Murder Mystery weekend for groups of detectives, be interesting to see what this is to see how good they are 🙂
Sounds interesting!
I promise, Walt: I only murder on paper!
Jim, great article. And one I’m interested in, as I’ve been researching what to use for a new novel I’m doing. Wouldn’t the PC leave a suspiciously high level in the blood? And wouldn’t the M.E. find the injection spot?
Hi, ggiammatteo. Regarding your questions: PC is released with any muscle trauma & high levels result from a heart attach, so the ME would perceive that as normal. A perceptive ME would find an odd injection spot, but maybe not in an odd location & an ME might not even check if a cardiac event was the suspected COD. Happy writing!
I’ve seen on TV shows (Medium being one I remember now) people being poisined with potassium, but taking it orally, like mixed in a bottle of water. This would be a myth, right? To be fatal, potassium would have to be injected, or am I wrong?
You are correct, Carol. Our GI tracts are designed to absorb only so much potassium, not enough to be fatal – so an oral overdose is not feasible. To be fatal, potassium has to be injected.
Well, that was freaking me out as I was reading it. Oh the devious things that can be done.
Sir, if the victim is doctor himself and if he is on some injectable medicine for cardiac disease, can he visually differentiate between the regular drug he is taking and the potassium chloride which can induce cardiac arrest?
Please respond as it is required for my new novel plot.
The answer is “possibly” that this doctor would know the difference. Certainly, most injectable medications are clear and colorless, but different medications require different dilution volumes before infusion to protect from “burning” the veins. That is, some medications can be directly administered from a push of the syringe; whereas, other medication first need to be diluted by adding to a bag of saline solution (the amount will vary with the drug). So some research on your part will be necessary to get the details right.
Thanks for your interest and all the best on your new novel plot.
This was just the information I needed for my novel. So glad I found your blog. I can’t wait to investigate it further.
Thanks and great to have you as a regular reader on my blog
All the BEST in your writing!
Your website is amazing! I’m so glad I found it.
Question for you…
Do livestock veterinarians have access to SUX?
I was thinking of using either SUX or Ketamine in my novel 🤔
Thanks for following my website and for reading some of my blogs. The answer to your question is yes, vets do use succinylcholine in their practice, mostly in euthanasia instances. And, of course, ketamine is primarily used in veterinary medicine in addition to now being a popular street drug.
Thank you for the response 😀