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Drug/dosage to give someone to render them easier to drown (present day)
silentg_canada wrote in little_details

  • I've googled [best drugs to give prior to drowning], [best drugs to induce unconsciousness] but it wasn't super-helpful.

  • I've also researched Ketamine, GHB and Diazepam, and that's been more helpful.

  • I also looked through all the ~medicine:drugs posts here.

I have learned that Ketamine & GHB are both odorless & colourless, but I don't know if that's true of Diazepam. I've learnt that all three induce extreme relaxation, but I don't know if that is sufficient. I know that Ketamine is used in veterinary applications, but I don't know how easy it would be for an older (65-70) year old professional to acquire GHB.

Present-day murder mystery. A neighbour of the victim lures her to her death by dosing her with a drug in a drink he gives her, then drowning her.


  • The drug must be comparatively easy to acquire by an older gentleman who has no knowledge of the illicit drug world.

  • The drug must be tasteless enough to be administered in a regular (non-alcoholic) drink without being noticed.

  • The drug must make the victim much more susceptible to drowning (ideally, after the drug has taken effect, the murderer should be able to just push her into the water and she'd be too far gone to save herself).

  • I would love to know an approximate dosage.

  • Does not have to be any of the three drugs I've already looked into... any easy-to-acquire drug that fits the scenario would be great. I guess a muscle relaxant or sleeping drug would be fine too, but I'm finding it really difficult to figure out which ones could be administered without the recipient's knowledge.

Thank you!

I suppose it depends on how insensible you want your victim, but have you considered rohypnol (the date rape drug)?

They're not likely to be unconscious, though, just very very pliable and willing to follow orders. My partner got dosed with rohypnol at a club and it was awful. Unless I told him to do something he would just stand there, quietly weeping. This in itself was alarming because there was nothing normally quiet about the man - he was 6 feet of loud brash Brooklyn Italian. He was also not the obedient sort, so the fact that when I would say, "OK, change into your pajamas" he would do it - all while quietly weeping - was even more alarming. (So, OP, at least you have a description of what might happen if your character used this drug.)

The next morning, the last memory he had was of getting into the car after leaving the club.

Oh thanks, I forgot about rohypnol! That's a possibility, although I wonder if it would physically incapacitate someone enough for my needs.

Does your character have access to a veterinary surgery? That's the most likely place to get actual ketamine. It's an anaesthetic, so he's not going to get to take some home for a sick pet or anything, though.

Valium he can probably get from a doctor on prescription for anxiety and/or insomnia, or for a muscle spasm. Temazepam (for insomnia) might be another possibility that he could get on prescription. Both Valium and Temazepam are in fairly small tablets which can be easily crumbled and have a bitter but not strong taste, but it's difficult to completely dissolve them. They might be better in, say, cocoa or hot chocolate where a little bit of grittiness could go unnoticed. Rohypnol is the classic, but it's now coloured blue and much, much harder to get.

The issue with any drug like this is that it's very hard to determine a dose. For example, I took a quarter of a 5mg Valium for a neck spasm and was knocked out for 14 hours. Other people are barely affected by 10mg several times a day. An average person who doesn't frequently take the medication should be greatly affected by 10-15mg of Valium (2-3 tablets) or 20mg of temazepam (2 tablets), but it's no guarantee!

Seconded on the diazepam/Valium/other benzos being unreliable wrt dosage. I am the opposite of this commenter - I was given 20mg for a procedure to knock me out and it didn't. It SO didn't.

With GHB, the person receiving the drug just might die on their own before being pushed in the lake. The line between the "fun" dose and the "dead" dose is pretty narrow.

Have you considered having your hero just get her very drunk? He could make her fruity mixed drinks and put something like Everclear in it. Almost tasteless and very high alcohol levels.

That's all good info, thanks. I'm leaning towards the dose being in a designer coffee, so maybe a bitter pill won't be tough to swallow. :)

FWIW, diazepam has a pretty nasty aftertaste - it will do what you want it to do but it's going to leave a residue if dissolved (unless your character has access to the IV form, so if they're a doctor, or work at a hospital.) Pharmacies will usually only have the tablet form on the shelf.

Doxylamine is a antihistamine sleep aid. In Australia you can buy it in liquicaps - those gelatin capsules filled with liquid. It has a muscle relaxant effect and it's strongly sedating. It's also available in over the counter, and it's sometimes used to treat allergies, so there's a explainable reason for the person to have it in their system. It might give you another option.

I am actually on a sister drug to doxylamine, called hydroxyzine. In the US, hydroxyzine is often prescribed for chronic skin allergies and also anxiety. I am normally a light sleeper and on this stuff I have slept through a (small) earthquake. However, it is quite bitter. Maybe if it was baked into a brownie or something else?

OP, is it possible for your character to also put alcohol in the person's tea - or alternately to convince the character to have a glass of port or sherry? Alcohol magnifies the effect of any sedating drug.

Thanks for the suggestion, but the drink will have to be non-alcoholic.

That's a really good suggestion. OTC is helpful as well, because my perp is really light on resources.

Clonazepam is almost tasteless, actually it just tastes a little sweet, oddly as compared to other benzodiazepines. It's readily prescribed for generalized anxiety. In a benzo-naive user, 20mg would easily render them unable to swim. One thing to note is it has a long onset time, about 45 minutes to an hour. Also, a probable autopsy would show the drug in the system, making it suspicious.

But - if the murderer could put the story out there that she had been anxious that would be enough to explain the drugs in her system. And also, depending on where it happens, the medical examiner might not even test for it. It's expensive to run a drug test, so sometimes cops will just go with the most obvious mode of death and leave it at that.

Average starting dose would be 0.25 to 0.5 mg, so 20 mg would at least be considered an intentional overdose. Drug tests are not expensive; I believe it would be standard procedure in most places. Leading the authorities in the story to think suicide would be more believable, but it sounds like the kind of thing you see people going to prison for on Discovery ID.

That's good info thanks. Showing in an autopsy is absolutely no problem, but the long onset time is a concern.

Something not-very-reliable but which would be really easy for your murderer to get ahold of is first-generation antihistamines. They're drowsy-making on their own, and can become much more so when in the system at the same time as alcohol (they're depressants on similar parts of the brain, IIRC?). At higher doses, they can mess around with physical coordination all on their own. Or at lower doses, they could simply induce the victim to conk out then interfere with their ability to self-rescue if rolled into the pool.

Diphenhydramine (Benadryl) is particularly known to have sedative effects, and is sold in liquid form (at least for children and dogs; not sure about adults) which could be easily added to a cocktail that's on the fruity/sugary side.

The downside is that everyone reacts a bit differently - both in terms of "how much does a given dose of the drug affect them?" and "what exact symptoms will they display?" - which makes the scheme not very reliable.

Whoops, misread - *non*-alcoholic drink. Sorry!

Diphenhydramine is really bitter. It would be difficult to disguise even in a strong drink, I suspect.

Thanks for the suggestion! I'll look into the effects without alcohol, since no alcohol will be served to the victim.

Hmm... trazodone (which is an antidepressant, but is frequently prescribed off-label for insomnia) has a strong sedating effect. If you gave enough it would probably make it difficult for her to swim, although I don't know if she would be as far gone as you want. It's a little bitter and has an odd numbing effect on the tongue, but might be able to disguise it if the drink was sugary enough.

Thanks everyone! Some info I found.


2014-08-14 03:31 am (UTC)

I did the same search for rohypnol that I'd done for the other drugs I mentioned, and I found an interesting forum post on GBH, rohypnol and other drugs.


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