10 of the Most Dangerous Drugs

There have been any number of studies on what might be the world’s most dangerous drugs over the years. A problem many of these have is they focus on only one aspect of what makes any particular drug harmful. For example, how much damage to society does it cause, is it dangerous in the long term / short term, or how addictive is it. To really get to grips with this question all these factors need to be taken into account; but also we need to look at the actual statistics – how many people are actually seriously harmed by these drugs.

The first thing to do is forget any government classification of narcotics. These are partly driven by vested interest, partly by politics and often out of date with the reality on the street. It was the chief British drugs advisor, Prof. David Nutt, who pointed out that horse riding was statistically far more dangerous than taking ecstasy. However, one is a highly illegal drug whereas the other is considered a wholesome pursuit. So, this would lead me to think that it isn’t our governments concern for our safety that drives their drug policies.
Perhaps the most glaring inconsistency in almost any government’s ability to rank the danger of drugs is the fact that the only two that kill in their millions are perfectly legal whilst some schedule 1 / class A drugs are not toxic or addictive.

In this list of the 10 most dangerous illicit drugs I am going to focus on the danger the drug presents to the user. So I’m looking at how toxic the drug is, how addictive it is and how quickly you will cease to be a functioning human being once you start using.

10. Ketamine


Ketamine in powder form

AKA: K, Special K, Vitamin K, K2

Price: $$$

Ketamine is perhaps best known as a horse tranquiliser although it was developed for human use. It was intended to replace PCP (Angel dust) as a shorter lasting anaesthetic and it is still used in certain situations. However, there are several side effects that come in to play as the drugs effects wear off, most notably hallucinations. These usually last less than 2 hours along with feelings of detachment, which can be fairly extreme.

Ketamine overdoses are potentially fatal and there is no effective antidote. A patient may need to be put on life support to maintain respiratory function until they can breath on their own. Possibly the greatest risk to users of ketamine though is the direct psychological effects or the “K-hole”. The user may become so detached from reality that they endanger themselves. For example two eminent ketamine experimentors wound up dead, one from hypothermia and the other drowning.

There is plenty of evidence of ketamine being addictive and once this happens tolerance soon builds up. Along with this go several side-effects such as bladder problems, memory loss and various other psychological impairments. Withdrawal may result in minor, but permanent nerve damage.

9. Amphetamines

Snorting amphetamines

Snorting amphetamines

AKA: Speed

Price: $$

It may seem strange but one of the few legitimate medical uses of the stimulant amphetamine is in the treatment of attention deficit hyperactivity disorder (ADHD). For most people though, the effects of taking amphetamines are feeling energised and confident.

There is a risk of addiction, but the evidence is that this is only particularly likely with heavy use. If someone does become addicted then tolerance grows quickly requiring ever increasing doses. Surprisingly amphetamine overdoses rarely prove fatal and there is little evidence to show that it can result in heart attack, strokes or other cardiovascular events.
What excessive doses can do is effectively change the wiring of the brain making addiction stronger or more likely.

Perhaps the best known and most sinister of amphetamines side effects is “speed psychosis”. One study found that nearly 20% of heavy users had clinical levels of psychosis. Of these up to 15% never fully recover. The symptoms of amphetamine psychosis are very similar to schizophrenia with hallucinations, delusions of persecution and extreme agitation being common.
And this is why amphetamines make it onto this list.

8. Benzodiazepines


Temazepam – a benzodiazepine

AKA: Benzos, downers, duck eggs

Price: $

Valium (diazepam) is probably the best known of all prescription sedatives. They were developed partly in an effort to replace barbiturates (see below) as an anti-anxiety/depressant. Whilst they are somewhat less likely to result in fatal overdose they are highly addictive. Benzodiazepines are also widely available, this has made them the most widely abused class of psychoactive drugs in America.

Much of the misuse of benzodiazepines revolve around managing other drug use, e.g. to make heroin or amphetamine come downs more tolerable. Whilst there is evidence of benzodiazepine addiction alone most users seem to have a multi-drug problem.

What is interesting about this class of drug is the problematic behaviours caused are exactly the opposite you would expect from a drug considered a sedative. For example in the 1990s in the UK, at the height of the ecstasy-fuelled rave scene there was more violence surrounding the use and supply of the benzodiazepine tamazepam than all the other party drugs together.
The same appears true for users. In what are termed paradoxical effects people using these drugs may end exhibiting symptoms the very opposite of those the drug is intended to treat. These symptoms often include psychosis and higher levels of psychopathy. Studies have also shown use of benzodiazepines increases risk taking behaviour.

7. Methadone


Methadone – © Fred Shakeshaft


Price: $$

6. Barbiturates


Prescription barbiturates

AKA: Downers, red devils, pink ladies, purple hearts, goofballs

Price: $

Barbiturates have been around for a long time and were once the drug of choice of the American housewife. They are a class of sedatives which were widely prescribed to treat depression, anxiety and even sleeping problems until the potential dangers were realised in the late 1960s. Since 1970 barbiturates have not been freely available, if they were they would appear higher up this list.

The drugs work by depressing the nervous system which in turns gives the user a feeling of relaxed contentment and even euphoria. They also reduce anxiety and inhibition, somewhat similar to the effects of alcohol. There is no lack of evidence to show the addictive powers of barbiturates and this is both physical and psychological. In fact barbiturate withdrawal is one of the most severe and can be fatal.

The true danger of barbiturates though lies in the ease in which users can overdose. There is a much finer line between a normal and a deadly dose than with most other narcotics. Over the years countless deaths have been attributed to accidental barbiturate overdoses including celebrities such as Marilyn Monroe and Jimi Hendrix. However, even in “safe” doses barbiturates can eventually kill you with a range of physical and mental side effects.

  • George

    seriously? i cant believe you have cocain over krokodil. actually, you dont even have krokodil. its obvious you researched this a lot…

    • surfgatinho

      I did think about krokodil, but decided its use (outside Russia) was pretty limited. As the article is taking into account the social damage, as well as bodily damage, I didn’t include it.
      That said, the list ins’t quite finished and I may change it at some point…

      • Andrew

        Heroin is. The most hardest drug to come off I no 30 years on it an am still battling with it

        • Richard

          Alcohol and tobacco are by far heads and heels above all other drugs in use, abuse, deaths, families, lives ruined and health issues. Alone, either one are related to more deaths than your whole list combined. Ridiculous that neither one is listed but then again, they are not considered glamorous and also legal, making them very easy to be overlooked and forgotten which only adds to their danger

          • surfgatinho

            Er, both of them are on the list, and in the top 5…

  • Lowne Wolfe

    Wrong, ketamine is NOT called k2. K2 and Spice were brand names of products which, in earlier formulations, mimicked cannabis as they activated THC receptors. It was intended to be used as a research chemical and never to be ingested by humans. The K2 brand is no longer sold. K2 is now the street name or slang term for similar products. Each year the current formulation was made illegal, jwh-018 and jwh-073 being the earliest. It is made by spraying the chemical on dried herbs which the user then smokes or vapes. It is sold as “incense” and illegal in most states but not all as the packages say “not for human consumption”. Unlike earlier formulations (which are now all illegal and class I drugs) the latest formulation (am-2201) has been causing kidney failure and digestive issues in MANY MANY users, it has killed many people as well. I can personally attest to k2’s affects, lost kidney function for 2 months myself and I got VERY lucky I didn’t die. But again, ketamine is not called k2.

    • surfgatinho

      You’re right. I’ll fix it when I get round to finishing this article off properly.

  • Misanthropia

    This is why women shouldn’t be housewives or they’ll start taking drugs out of boredom LOL

  • Tom

    This list is pretty ridiculous. There are a LOT of errors. I would know, having been addicted at one point or another to a few of these.

    The Cocaine entry at the top of this list is ridiculous!
    Why Barbs are priced at 1dollar, given that it would cost a FORTUNE to get hold of them if you even could.
    Also, “The first thing to do is forget any government classification of narcotics”. Narcotics actually refers to a specific class of drugs, sedative analgesics…opioids/opiates. This belies the fact you aren’t well-researched in this area – rookie error…
    “Ketamine overdoses are potentially fatal and there is no effective antidote” – Ketamine is one of the safest drugs in terms of overdose! Of all ones to pick for overdose harm! The recreational dose is a tenth of the anaesthetic dose and you would pass out quite healthily before getting enough Ket in your system to overdose. The risk of Ket is when you hole in an unsafe environment.
    Let’s not forget that you neglected:


    You shouldn’t put content out there that is incorrect…it leads to misunderstandings for people believing inexperienced, poorly researched articles. You are doing damage!

    • Just Me

      Tom, rather than creating even more entries for more types of drugs, it makes more sense to group similar drugs together:

      Opioids, such as heroin, methadone, fentanyl, krokodil, etc.

      Stimulants, such as speed, crystal meth, cocaine, flakka, etc.

      Putting drugs like speed and crack different classes with different dangers is like creating a separate category for beer, wine, vodka, and Everclear. Sure, Everclear is more dangerous than beer, but it’s still all the same drug.

      You do have a few important ones on your list which don’t fall into any convenient categories, like Datura and PCP. It’s good not to overlook those, so good catch.

      • Luken

        Except the recreational components of Beer, wine, vodka and everclear are all literally the same chemical.

        Amphetamines, crystal meth, MDMA and cocaine are not. Cocaine isnt even in the same chemical family.

        Their long term effects, how they interact with the body, and the level of danger they present are all completely different regardless of dosage. Lumping them together is uninformative and useless.

        And even if we are talking about effects, calling something a “stimulant” is an extremely vague umbrella term, it doesnt at all mean all the drugs have the same actual effect. Cocaine, MDMA and crystal meth are all “uppers” yet cause completely behavioural patterns.

        Its almost the level of granularity as trying to group alcohol, psilocybin, cannabis, and xanax together as “downers.”

  • Blade2001

    Kroiodil and bath salts are way more dangerours

  • Михаил Отте

    My top 5:

    1. PCP
    2. Datura/Anti-Cholinergics
    3. Meth
    4. Barbituates
    5. Heroin

  • Chowderbatter

    Is there a reason heroin is spelled with an E in this article?

    Also, I’d say tobacco and alcohol have to easily top any list of most deadly. They may or may not be as addictive as other more “dangerous” drugs, but they are so common, so pervasive, and they directly impact non-users in a way that all of the others combined do not. Second hand smoke inhaled by children, family, co-workers, passersby. Alcohol related abuse and fatalities.

    All other drugs combined do not do as much damage as either one of those two alone. It’s not close. And everyone on the planet knows alcohol and tobacco addicts.

  • Luken

    I appreciate the sentiment re alcohol but in a literal deadliness league table of “recreationable” chemicals, alcohol and cocaine aren’t in the big leagues at all.

    Cathinone, fentanyl, myristicin, the ongoing production line of synthetic canniboids, whatever other dystopian substances will be flushed out of the woodwork in future…ethanol is the bigger scheme of things is a fairly mundane and primitive drug.

    Undeserving of its privilege as the “acceptable drug that isn’t even a drug”, far worse than some other drugs in certain ways (not least its paucity of spiritual depth), but still just a middle weight in the danger stakes. Its a fairly solid social drug really, it doesnt alter your mindstate, justs numbs the senses, shuts down higher brain function for a while, charges you with a hangover the next day, then you get on with your life.

    Long terms defects emerge but all matters of the body go south in the end, and no recreational drug in Humankinds current toolkit is going to help you with that.

  • Luken

    Good point. I find even the liberal minded to be prone to lax thinking on this topic, often failing to differentiate between chemical and mixture, psychoactant and metabolite.

  • Kevin

    This list, and the reasoning behind it, makes it fairly obvious the writer has neither done most (if any) of the drugs on the list; nor bothered use cited, peer reviewed research in his studies. Anyone can type in a drug and find one article riddled with speculation and half truths, which is exactly what was done. It’s journalists like this that make you realize you don’t need a degree, or even a highschool diploma to publish an article and spread the word of an idiot.

    • surfgatinho

      You criticise, yet put forward no alternatives or no actual reason why you disagree – oh, except it doesn’t have citations. Using your same approach I will just say, you’re wrong, but I’m not going to justify or explain that…

  • Kevin

    My previous comment had a lot of errors and poorly written sentences. But who cares, I don’t have a degree, or a high school diploma, and I’m balls deep into the fourth most dangerous drug on this list. Publish me an article.