Activated charcoal tablets are unlikely to be effective in counteracting date rape drugs; individuals who have been given date rape drugs should seek medical attention

Drug-facilitated sexual assault (DFSA) refers to any sexual assault where alcohol or drugs were used to compromise an individual’s ability to give consent. The Rape, Abuse & Incest National Network (RAINN) defines two ways a DFSA can occur. In the first, the perpetrator takes advantage of someone’s voluntary use of drugs or alcohol. In the second, the perpetrator intentionally forces the victim to consume drugs or alcohol either with or without their knowledge.

In 2008, the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), an agency in the European Union, released a technical data sheet on DFSAs^[1]. According to the EMCDDA, reporting on DFSA’s suggests that over the last 10 years there had been an increase in the use of alcohol and drugs to incapacitate victims of sexual assault. The Crime Survey of England and Wales (CSEW) released in 2018, reported that six percent of assault victims had been drugged by the offender.

A number of drugs, known as date rape drugs, are commonly associated with DFSAs. The most commonly associated substance is alcohol^[1]. According to RAINN, perpetrators may also use “prescription drugs like sleeping aids, anxiety medication, muscle relaxers and tranquilizers.” Two of the most commonly mentioned street or club drugs include the sedative flunitrazepam–also known as Rohypnol or roofies– and the central nervous system depressant Gamma-hydroxybutyrate (GHB).

Much has been written about what precautions individuals can take to avoid DFSAs – for instance, don’t leave your drink unattended. While, advice on what to do if you believe you’ve ingested a date rape drug involves seeking medical care. For this reason, it’s not surprising that a Facebook post from 2019 claiming that charcoal activated tablets can counteract date rape drugs went viral again in June 2021. As of 23 June 2021, the post was shared over 135,000 times.

Although activated charcoal is used in many instances to treat poisonings, individuals who have been given a date rape drug, should seek medical attention rather than rely on an activated charcoal tablet. Toxicologists who reviewed this claim for Health Feedback concurred that activated charcoal tablets would probably not work against date rape drugs for a number of reasons we explain below.

 

What is activated charcoal?

Charcoal, the byproduct of heating wood, is activated by steaming with really hot water or acid. This creates a number of pores on the surface of the charcoal, increasing its surface area to bind to poisons and other substances.

Many substances, including chemical poisons and medical drugs, are adsorbed by activated charcoal^[2]. What this means is that, these substances are attracted to the surface of charcoal and bind to it. It’s for this reason that many water filtration systems use activated charcoal to remove impurities such as chlorine.

Activated charcoal isn’t only used in filtration systems. “Activated charcoal is often given orally in the emergency treatment of poisoning,” explained Kent Olson, a retired clinical professor of medicine and pharmacy at the University of California, San Francisco [read Olson’s comment in full below]. “Charcoal works by binding to ingested drugs and poisons, preventing or reducing absorption of the substance into the bloodstream.” Activated charcoal is the most frequently used method of gastrointestinal decontamination in the developed world^[3].

However, though activated charcoal is sometimes called an “universal antidote,” this characterization is incorrect; many substances are not fully adsorbed or not adsorbed at all by activated charcoal^[2,3]. The effectiveness of activated charcoal, Olson explained, depends on a number of factors: “how readily it binds to the ingested poison; the amount of charcoal given compared to the amount of ingested toxic substance; and the time delay between when the poison was ingested and the administration of charcoal.”

The realization of the limitations of activated charcoal has resulted in a decrease of its use in acute poison patients^[3]. In 1999, poison centers in the U.S. recommended single dose activated charcoal over 136,000 times; by 2013, that number had decreased to around 50,000^[3].

 

Can activated charcoal counteract date rape drugs?

“Charcoal does not counteract or reverse the effects of the drug,” Olson pointed out. “It can only reduce its absorption–so ideally it should be given before the offending drug or very soon after.”

When it comes to date rape drugs, Tobias Zellner, a medical doctor at the Technical University of Munich, believes the benefits of activated charcoal are minimal. “The problem is that most date rape drugs (like GHB) are odorless, tasteless and have a rapid onset. At the point of time when the victim notices the first symptoms, a major part of the drug has already been absorbed, so taking activated charcoal would not have a relevant effect anymore,” he explained [read Zellner’s comment in full below].

Olson also mentioned the importance of timing. “Small volumes of the date rape substance, as a crushed pill or liquid, are usually taken up into the body fairly quickly and are probably completely absorbed within about 20-30 minutes, so if the charcoal is going to have any effect it would need to be given immediately.”

Activated charcoal would also have no impact on alcohol, which is the substance most commonly associated with DFSAs. It “is not effectively adsorbed to charcoal, so if alcohol is the only intoxicant the charcoal is worthless,” said Olson.

Both Olson and Zellner mentioned that the dosing of activated charcoal is another issue, with the amount of activated charcoal in tablets being too low to have an effect. “The amount of charcoal in each activated charcoal tablet is relatively small (150-300 mg per tablet); to take a dose equivalent to what is commonly used in a hospital emergency department would require about 150-200 tablets,” explained Olson.

Another issue is the formulation of activated charcoal. “The preferred formulation is powder in a suspension with water,” explained Zellner. If activated charcoal is taken as a tablet, “it will never reach a proper elimination.”

Lastly, date rape drugs can cause reduced or loss of consciousness and coma. These, Zellner said, “are strict contraindications for taking activated charcoal because of the risk of aspiration.” Accidental aspiration of activated charcoal can cause respiratory distress^[4]. In hospital settings, when activated charcoal is given to a patient who can’t swallow, it’s delivered via a stomach tube ^[2].

 

Conclusion

Though activated charcoal is the most used method of gastrointestinal decontamination in the developed world, an activated charcoal tablet would not be useful to counteract date rape drugs in the manner described in the Facebook post. The dose of activated charcoal in tablets is too low and the formulation is not ideal. The activated charcoal tablets would need to be taken soon after the date rape drug, which can be hard because many of the drugs associated with DFSAs are odorless and tasteless, and are absorbed quickly by the body. Lastly, activated charcoal would have no effect on alcohol, which is the drug most commonly associated with DFSAs and does not adsorb to activated charcoal.

As Zellner said in his review of this claim: “I would strongly advise against taking activated charcoal and feeling falsely reassured, but rather directly go to the next hospital or call an ambulance.”

Activated charcoal is often given orally in the emergency treatment of poisoning. Charcoal works by binding to ingested drugs and poisons, preventing or reducing absorption of the substance into the bloodstream. Its effectiveness depends on several factors: how readily it binds to the ingested poison; the amount of charcoal given compared to the amount of ingested toxic substance; and the time delay between when the poison was ingested and the administration of charcoal. Charcoal does not counteract or reverse the effects of the drug, it can only reduce its absorption — so ideally it should be given before the offending drug or very soon after.

There are a number of so-called “date rape” drugs that can induce drowsiness or coma, making the victim incapacitated to resist or recall a sexual assault. These include gamma hydroxybutyrate (GHB), flunitrazepam (Rohypnol) and other benzodiazepines, diphenhydramine (Benadryl), clonidine, and many others. Perhaps the most common of these substances is alcohol, which can be used alone or in combination with other date rape drugs to cause intoxication. For all of these the effect of the drug is entirely dependent on the dose taken.

If charcoal can reduce the dose of the drug that is absorbed into the body, could taking charcoal tablets after you suspect someone has given you a date rape drug prevent you from becoming intoxicated? Probably not, for the following reasons:

• Alcohol, the most common date-rape drug, is not effectively adsorbed to charcoal, so if alcohol is the only intoxicant the charcoal is worthless.
• The amount of charcoal in each activated charcoal tablet is relatively small (150-300 mg per tablet); to take a dose equivalent to what is commonly used in a hospital emergency department would require about 150-200 tablets.
• Small volumes of the date rape substance, as a crushed pill or liquid, are usually taken up into the body fairly quickly and are probably completely absorbed within about 20-30 minutes, so if the charcoal is going to have any effect it would need to be given immediately.

·  While it is possible that taking several tablets of charcoal before ingesting a suspect date-rape drug might conceivably have some protective value, remember that it would have no effect on any alcohol ingested and would have only limited benefit for other drugs, depending on the specific drug. I am not aware of any well-documented studies showing a benefit of prophylactic charcoal in such a scenario.

The use of activated charcoal to counteract date rape drugs seems to be minimal in my opinion. In theory, activated charcoal would stop some of the absorption of the most common rape drugs (although there are multiple substances) in the stomach. The problem is that most date rape drugs (like GHB) are odorless, tasteless and have a rapid onset. At the point of time, when the victim notices the first symptoms, the major part of the drug has already been absorbed, so taking activated charcoal would not have a relevant effect anymore. Furthermore, one of the symptoms of date rape drugs is reduced consciousness or coma, which are strict contraindications for taking activated charcoal because of the risk of aspiration.

Another problem is the dosing of activated charcoal and the formulation. One tablet –  as claimed in the post – is not nearly enough and in tablet form it will never reach a proper elimination, the preferred formulation is powder in a suspension with water.

Overall I see no practical use for activated charcoal to counteract date rape drugs, certainly not in the way described in the post. So I would strongly advise against taking activated charcoal and feeling falsely reassured but rather directly go to the next hospital or call an ambulance.

 

REFERENCES

• 1 – EMCDDA (2008) Sexual assaults facilitated by drugs and alcohol. Technical Data Sheet.
• 2 – Zellner et al. (2019) The Use of Activated Charcoal to Treat Intoxications. Duetsches Ärzteblatt International.
• 3 – Juurlink (2016) Activated charcoal for acute overdose. British Journal of Clinical Pharmacology.
• 4 – De Weerdt et al. (2015) Rapid-Onset Adult Respiratory Distress Syndrome after Activated Charcoal Aspiration. A Pitch-Black Tale of a Potential to Kill. American Journal of Respiratory and Critical Care Medicine.