Irene has obviously used the drug before:
“Don’t worry, I’ve used it on loads of my friends,”
And she also knows what the effects are:
“He’ll sleep for a few hours…make sure he doesn’t choke on his own vomit.”
The drug does not have to be a designer substance made purely for the sexual fantasies of Irene’s clients, nor does it have to be a banned substance. In fact I think it could be a common prescription drug, which would make Irene’s use of it illegal but the drug itself is probably widely used by the medical profession.
It’s effective given via an injection into the muscle rather than the vein and causes confusion and loss of control almost immediately. Irene hints that in the longer term it acts as a heavy sedative – so heavy that even vomiting won’t wake you up.
I personally thought that it would be some form of typical antipsychotic like haloperidol or chlorpromazine (an old class of drugs that were used to treat psychosis). Given in large enough doses these drugs are potent sedatives which will knock people out completely.
However Kate 221B has pointed out the flaw in this theory: injected antipsychotics don’t work that fast. Sherlock was collapsed on the floor and unable to get up in just under two minutes.
A more suitable drug Kate221B suggested is ketamine.
I like this theory for two reasons:
- Ketamine is a common recreational drug in the UK so Irene would have no problems getting hold of it
- Ketamine is also used as emergency anaesthesia in battlefield medicine. Even if John has never personally administered it, he would be familiar with its effects. This could explain why he doesn’t panic in this situation.
Back at 221B Sherlock’s difficulty speaking, wobbly movements and confusion (looking for Irene under the bed) are common symptoms of someone emerging from ketamine induced sedation.
Ketamine causes nausea/vomiting (hence Irene’s warning to John) and interesting it can also cause hallucinations and vivid dreams. I wonder if the whole Sherlock and Irene in the valley scene is an elaborate romantic hallucination on Sherlock’s part.
It is well known in anaesthetics that young men (and women) who are not given enough ketamine won’t become sedated straight away – they become psychotic instead. It’s known as going down the K-hole. Could this be perhaps why Lestrade got involved in the first place? Did John call him for help to restrain Sherlock and get him back to the flat because a psychotic Sherlock hallucinating about Irene would be more than John could handle.
I doubt John phoned Lestrade to report the dead bodies. We can already hear sirens in the background when Irene jumps out of the window - so John knows the police are already coming. These police won't be CID, they would be the nearest beat coppers responding to the 999 call. CID only get involved after it has been confirmed that a definite serious crime has taken place. Also Lestrade is not the only DI in London! The shooting at Belgravia could be assigned to any of the CID teams operating in the metropolitan area. Calling Lestrade to report the crime is fairly superfluous, besides it was supposed to be a semi-covert operation anyway. So I believe the only reason John involved Lestrade was so that they could both drag Sherlock back home.
Given that Lestrade knows about Sherlock's history with drugs, John could probably just pass it off as Sherlock being Sherlock.
The other possibility that Kate221B suggested is GHB the notorious date rape drug. Frankly I wouldn’t put it past Irene to have GHB in her draw and enjoy using it. GHB causes rapid sedation just like ketamine and can also lead to nausea/vomiting. In fact choking on vomit/inhaling vomit is one of the most common causes of death in people who take GHB. However getting the dose wrong for GHB is dangerous because if you overdose someone it will make them stop breathing. Whereas ketamine is relatively safe in comparison.
So I personally think that Irene injected Sherlock with ketamine. Does anyone else have other suggestions? Comments welcome.