Benzos, Blues, BZDs, Tranks, Z-Bars, Downers

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Benzos, or benzodiazepines, are a class of prescription drugs which usually come in the form of tablets. They are primarily used to treat anxiety and insomnia due to their depressant effect. Recreational users typically take benzos for their euphoric, relaxant and sedative effects. They are sometimes combined with other drugs to enhance the effects of depressants, ease the comedown from stimulants or try to alleviate a bad psychedelic trip. They should not be confused with Z-drugs, BZP and ‘benzo fury’ which are not benzos.

The first benzodiazepine was synthesised by accident in 1955 in the laboratories of Hoffman-La Roche and has since become the most widely prescribed drug in the world. Currently, around 20 exist, each with varying durations of action dependent on their clinical use.

Prescription drugs are often best known by their brand names, but they also have generic compound names. Some of the most common benzos are Valium (which contains the compound diazepam), Klonopin (clonazepam), Xanax (alprazolam) and Ativan (lorazepam).


Avoid alcohol

Mixing benzos with depressant drugs such as alcohol, opioids and other benzos can be life-threatening due to risk of respiratory depression.


Don’t drive

Benzos decrease your coordination and alertness making driving very dangerous (and illegal). (1)


Stick to a dose

Tolerance develops rapidly. If you feel like you need to take more to achieve the same effect, try abstaining for a few weeks to prevent the risk of dependence.

Common substitutes and adulterants

Sometimes the drugs we think we are buying turn out to be something very different. Knowing the common substitutes and adulterants is an easy way to protect yourself and your friends.

As benzos are prescription drugs in many countries, most of what is sold originates from pharmaceutical companies and is subsequently diverted to the black market. Unfortunately, high demand has generated illegal unregulated production. This means that dosage cannot be certain and harmful contaminants or cutting agents can be present.

Fentanyl has been found in counterfeit Xanax pills which were the cause of several deaths in the UK. Fentanyl is an extremely strong opioid and its combination with benzos can be fatal due to an enhanced depressant effect of each drug. See the harm reduction box for more information.

‘Etizolam’ has also been sold as a substitute for Xanax. Etizolam is a benzodiazepine analogue, whose effects are similar to benzos. It is not a regulated substance like other benzos and its effects on humans are not fully known.

Effects of benzos

You can find here the most common effects of benzos. Despite the large variety of benzos, their effects are comparatively similar. Where they diverge is in the timing, duration and intensity of these effects. This list is not definitive, nor exhaustive; you may not experience all these effects every time you consume benzos, and your friends around you may have a vastly different experience, possibly experiencing effects not listed here. Remember, the likelihood of experiencing negative effects is much greater at high doses.

The effects are (from positive to negative) (2,3):

  • Reduction of anxiety and aggression
  • Relaxation
  • Euphoria
  • Sleepiness
  • Loss of time
  • Weight gain or loss due to appetite fluctuation [4]
  • Poor motor skills due to impaired coordination
  • Muscular weakness
  • Poor concentration and memory
  • Dizziness
  • Emotional blunting
  • Dry mouth
  • Constipation and urination problems
  • Depression and suicidal thoughts

Paradoxical symptoms sometimes occur, possibly due to acute withdrawal syndrome. They are more commonly seen with short-acting drugs whose action wears off rapidly:

  • Irritability
  • Anxiety
  • Aggression
  • Increase in risk-taking behaviour
  • Increase in sexual arousal
  • Insomnia
  • Hallucinations

Sometimes we take too much, here’s what you can expect to happen when overdosing, both internally and externally so that you might detect the signs of an overdose in others (5).

  • Blurred vision
  • Slurred speech
  • Lack of coordination and shuffling walk
  • Irregular heartbeat
  • Difficulty breathing and swallowing
  • Memory loss
  • Loss of consciousness

Dose and onset of benzos

How? How Much? When? For how Long?

These are important considerations. The way you consume benzos can vastly impact the experience. The same applies to the dose taken, the effects of which will vary depending on many factors such as your weight, gender, metabolism, and tolerance from previous use.

Read our section on dosing for more information.

How you take benzos matters...


Due to their origin in the medical setting, benzos typically come in tablet form. Taking tablets orally is our recommended method for minimal harm. These can be swallowed, but also chewed or dissolved under the tongue for faster absorption though their taste is unpleasant. Most tablets can easily be split in half to control dosage. Most benzos have a short onset of action when swallowed.

Snorting benzos

Snorting benzos does not seem to produce a stronger or faster high. Although evidence is limited, it is thought that benzos are not readily absorbed through the nasal cavity due to their water insoluble nature. The effects of the drug would mostly come from unabsorbed residue dripping into the throat. Snorting benzos carries the risk of nasal damage in the long-term and is reported to be very unpleasant.

Intravenous/intramuscular benzo injection

Injecting puts you at risk of HIV and other blood-borne infections such as hepatitis C, as well as collapsed veins, bruising, and other unsavoury side-effects such as sooting. Many of these risks can be mitigated by always using single-use clean needles and rotating injection sites. Benzos are especially irritating and cause tissue damage, occlude veins and might lead to need for amputation (6).

How much benzos?

As discussed above, potency is where benzos differ, affecting the dose ranges and time course, with effects remaining fairly similar when taking comparable doses. As an example, the tables below show comparable light, common, and strong oral doses for four common benzos. For the endless other benzos that exist, this handy calculator allows you to make dose conversions.

Light: 0.25-0.5 mg

Common: 0.5-1.5 mg

Strong: 1.5-2 mg


Light: 0.25-0.5 mg

Common: 0.5-1 mg

Strong: 1-2+ mg


Light: 2.5-5 mg

Common: 5-15 mg

Strong: 15-30 mg


When do the effects of benzos kick in?

The START time below is when you will usually begin to feel the effects of benzos from the time when you first take it. DURATION is roughly the length of time you will experience the effects, after which the effects will start to wear off and you might start to feel the comedown effects.

Different benzos have different start time and duration which will depend on the dose, the individual and the contents of their stomach. If taken orally without being on an empty stomach the onset can be delayed, the effects slightly prolonged but also slightly diminished.

Start: 15-40 minutes

Duration: 5-8 hours

After-effects: 6-24 hours


Start: 20-45 minutes

Duration: 8-12 hours

After-effects: 8-48 hours


Start: 30-90 minutes

Duration: 10-24 hours

After-effects: 1-120 hours


Benzo interactions

If there’s one thing that can really be dangerous, it’s mixing drugs. We’ve compiled here the safety profiles of various mixes with benzos (legal and illegal) but don’t swear by them. As with all matters drug-related, everyone is different, and you can very easily experience an unexpected adverse reaction.

Benzodiazepines + ? =

Select a drug

Click one of the drugs below and see how it mixes with Benzodiazepines.


If you’re taking medication, you need to be extremely wary when taking illegal drugs. Their interactions with prescribed medication are often poorly researched and you will definitely not be warned by your doctor about it.

Drugs that inhibit cytochrome P450 isozymes (e.g. contraceptives, disulfiram, fluoxetine (Prozac), some antidepressants, antihistamines, antibiotics and antifungals) may result in increased effects such as sedation and impaired psychomotor function. A list of drugs which inhibit these enzymes can be found here.

It is reported that antacids decrease the absorption of benzos from the gastrointestinal tract thus decreasing their effects.

Harm Reduction for benzos

There are certain precautions you should take before doing benzos. The advice below helps you to be physically and mentally prepared before doing it. Furthermore, we want you to be safe, and just in case you have a bad experience or some of the unwanted side effects associated with DRUG, we have also provided information on how to take care of yourself when you are in full swing. Finally, there are those uncomfortable or undesirable effects after the high have worn out, we will provide you with some practical tips on how to have a better calm down and help you to reduce the harm done to your body and brain.

Head over to our ME section if you would like to know more about harm reduction.

Test your drug. Illicitly produced benzos are encountered frequently. These drugs might be cut with fentanyl and this combination is life-threatening. Therefore, we highly advise you to test your drug for it.

Set a dose regimen. Tolerance develops quickly so there is a tendency to increase the dose gradually. Do not increase your dose to prevent developing dependence. If you need more to achieve the same effect, try to have longer breaks.

Mind your heart. Stimulants speed up your heart while depressants slow it down. These mixed signals might cause dysrhythmias or heart failure (13). Avoid mixing these drugs if you have a heart problem.

Take Vitamin C. Benzos affect memory creation and can cause short-term amnesia. Some evidence show that high doses of Vitamin C can reduce this (14).

Avoid injection. Injecting crushed tablets causes severe complications such as tissue damage or death due to benzos’ high lipid-solubility (15). Injecting street benzodiazepine carries more danger as it is likely to contain other substances which may increase harm. Sharing injecting equipment further risks infections such as HIV, Hepatitis B and Hepatitis C. If you are going to inject benzodiazepine, use water-soluble benzos and new injecting equipment. Free needle and syringe exchange services are available around the UK. They provide sterile injecting equipment as well as advice to users.

Variation within ethnicities. Individuals of Asian heritage may have slower metabolism of benzos (16). It is advised to start with half the usual recommended starting dose.

Increased sensitivity of cocaine users. Regular cocaine users have an enhanced sensitivity to benzos resulting with more intense effects (17). It is recommended to use lower doses than the common dose.

Stick to your dose. Stimulants will mask the effects of benzos, so don’t be tempted to take more when mixing as you might overdose without realising.

Avoid depressants. When benzos are taken alone, an overdose is rarely life-threatening. However, when mixed with depressant drugs such as alcohol and opioids, their effects are potentiated, and this can lead to sudden loss of consciousness and respiratory depression.

No driving. Benzos decrease motor coordination and impair judgment increasing the risk of car accidents.

In the case of an overdose

If you think you or a friend is overdosing, seek medical help immediately by calling 999. Bring the pill containers with you to help the doctors determine the type of pills taken.

Benzos can cause an unexpected loss of consciousness and increase the risk of vomiting. Place your friend or yourself in the recovery position to prevent the risk of vomit aspiration.

Be careful. The after-effects of benzos can last for days. Even at low or therapeutic doses, benzos impair coordination. Avoid tasks which require motor skills.

Avoid depressants for the next few days. Due to their unpredictable duration of effect, benzos (including short-acting ones) still carry a risk of overdose with depressant drugs the day after!

Recover. Moderate exercise, stretching, hot baths and general relaxation exercises will help to cope with the anxiety and muscle stiffness which might occur.

For balance impairment, exercises such as standing on one leg, first with eyes open, then with eyes closed, can speed up recovery.


Risks of benzos

Benzos are primarily used for anxiety, which usually co-occurs with depression. However, benzos do NOT have antidepressant effects with the possible exception of alprazolam (18). On the contrary, benzos might exacerbate depression and cause suicidal behaviour and ideation as they depress the central nervous system.


The occasional use of benzos has a relatively low risk of harm. However, when used longer than 3-4 weeks, dependence is likely to develop and stopping the drug suddenly causes withdrawal symptoms. Therefore, it is best not to take benzos for more than 1-2 weeks.

Unlike many other recreational drugs, craving is not a major problem while withdrawing from benzos. It is the physical and psychological symptoms which makes it difficult. Symptoms may take up to 3 weeks to become apparent.

Withdrawal symptoms include anxiety-related symptoms such as panic attacks, insomnia, irritability, aggression, palpitations, nausea, depression and muscle pain.

Other signs include:

  • Tremor
  • Hypersensitivity to senses
  • Abnormal body sensations like pins and needles, tinnitus, metallic taste etc.
  • Hallucinations, paranoia, delirium
  • Derealisation and depersonalisation

In severe cases, sudden discontinuation can lead to life-threatening seizures or death (19).

Therefore, benzos should never be stopped suddenly. Instead, the dose should be reduced gradually, ideally with a doctor’s supervision.

Gradual dose reduction does not eliminate the withdrawal symptoms. Anxiety management and psychological support is equally important.

A helpful guide about how to withdraw from benzos can be found here.

In the long-term...

Long-term use, even at therapeutic doses, has been shown to cause cognitive impairment, affecting learning, memory and attention and may persist longer than the physical withdrawal symptoms (20).

There is some evidence suggesting that long-term use may increase the risk of dementia (21). However, the evidence is inconclusive.

Dangerous Conditions


Benzos are first-line treatment for status epilepticus. An increased tolerance due to recreational use can be dangerous in a state of emergency when benzos are needed to control the seizures. Additionally, a history of prolonged use, multiple exposure, and high-dose benzos consumption increases the risk of epilepsy (22). Withdrawal from benzos can also trigger seizures (23).


Benzos can exacerbate depression and cause suicidal behaviour and ideation because they depress the central nervous system.

Acute angle-closure glaucoma

Benzos can increase the intraocular pressure and can precipitate angle closure-glaucoma in susceptible eyes (24).

The Law on benzos

In almost all countries benzos are controlled medicines, meaning they can only be legally obtained by prescription from a medical doctor and recreational use is illegal. A rare few countries such as India and Cambodia sell benzos over the counter. Some online pharmacies sell and ship benzos to all countries regardless of their legal status, however you would be risking a criminal offence.


  • UK: Illegal
  • Germany: Illegal – small quantities for personal use is not prosecuted, other possibilities such as treatment is afforded instead
  • France: Illegal
  • Netherlands: Illegal
  • Spain: Decriminalised
  • Russia: Illegal


  • USA: Illegal
  • Canada: Illegal
  • Mexico: Illegal


  • Hong-Kong: Illegal
  • Singapore: Illegal
  • Israel: Illegal


  • South Africa: Illegal


  • New Zealand: Illegal
  • Australia: Illegal

More information, references, useful links...


Benzos are used in medicine; does it mean they are safe?

Benzos are medically approved drugs, primarily used to treat anxiety and insomnia. However, outside of these indications and without the supervision of a medical professional, a multitude of things can go wrong. Benzos have good safety profiles but remain very addictive, and can be very harmful when mixed with other drugs.

Do benzos have a cross tolerance with alcohol?

Cross tolerance between alcohol and benzos is generally assumed but not well documented in humans (25). The evidence is clear in animal studies. Even though alcohol and benzos act on different sites on GABA receptors, they still act on the same receptor. Theoretically, up or down regulation of the receptor due to any drug use will affect the response to both drugs.

Is there cross tolerance between benzos?

Yes, all benzos have cross-tolerance, meaning that taking one will after your tolerance of others (26).

Will taking benzos help me to come down from stimulants?

Just like having a coffee after alcohol does not make you anymore sober, benzos only mask the effects of stimulants, they do not counteract them. While this might give you a false sense of sobriety, it has been shown that mixing benzos and stimulants affected driving ability more strongly than either alone (27).

Does taking benzos with psychedelics reduce the risk of having bad trips?

Anecdotal reports suggest that taking a low dose of benzos before a psychedelic trip lessens the chances of experiencing a bad trip. This does however impair their ability to remember the trip. Benzos are also commonly used to alleviate an ongoing bad trip.


The erowid forum has an extensive curation of reported experiences from users spanning a large variety of topics including bad experiences and mixing with other drugs. Check it out here.


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