top of page

Flunitrazepam (Rohypnol)

the molecular structure of rohypnol
  • Flunitrazepam, commonly known by the trade name Rohypnol, is a central nervous system depressant in the benzodiazepine drug class. The sedative effects of flunitrazepam are around 7 to 10 times stronger than those of diazepam (Valium).

    Rohypnol is also used illicitly. The drug has been associated with sexual assault cases, in which the drug is given to the victim without their knowing or consent, by addition to their drink. Rohypnol is tasteless and colourless, therefore, the victim may not notice that their drink has been tampered with. This often renders the victim heavily sedated and can cause strong amnesia (loss of short term memory) leading the victim to have little to no recall of the assault. The drug is sometimes referred to as a “date rape” drug.

  • Flunitrazepam itself exists as a white powder that can be made into tablets.


    When used illicitly, and with intent to sedate a person without their consent, the tablets are often crushed up and put into (often alcoholic) drinks. In an effort to combat the use of the drug to spike drinks, manufacturers began to add colouring dye to produce olive green tablets that dye liquid blue, making it more noticeable if a drink is spiked with the drug. Not all flunitrazepam tablets contain this dye.


    Users who intend to take the drug themselves may also swallow whole tablets, crush them up and snort them and in some cases inject liquid flunitrazepam.

  • Like other benzodiazepines and Z drugs (other sedative-hypnotic drugs such as Zopiclone), flunitrazepam binds to GABAA receptors in the brain. This potentiates the effects of the neurotransmitter GABA (Gamma-Aminobutyric Acid) at these receptors which reduces activity in the brain, especially those which control anxiety, sleep, memory, reasoning, and essential autonomic functions such as breathing and heartbeat.

  • Due to its powerful sedative effects, flunitrazepam is used in a medical context in Germany, Ireland and Iceland to name a few countries. Here they are used to treat insomnia when other medicines do not work, however, it is not used in the long term for this purpose due to an increase in the risks with sustained use. The drug is also used as a pre-anaesthetic before operations.

  • The effects of flunitrazepam can be felt around 15-20 minutes after consumption with these effects lasting for around 4-6 hours and up to 12 hours in some cases.


    These effects include:

    • Sedation

    • Muscle relaxation

    • Reduced anxiety

    • Dizziness

    • Loss of motor control

    • Decreased reaction time

    • Slurred speech

    • Confusion

    • Amnesia

    • Aggression

    • Excitability

  • Using flunitrazepam poses risks to both physical and mental health.


    If someone takes an overdose of flunitrazepam, they can suffer unpleasant and potentially harmful effects. Overdoses can lead to confusion, slurring of speech, sleepiness, loss of coordination and collapse. If someone has taken enough to become unconscious, there is a risk of inhaling and choking on stomach contents which can potentially be fatal and breathing and respiratory rate can slow down or even stop.


    The danger of severe harm and death is much greater if flunitrazepam is taken with other sedative drugs such as alcohol, heroin or GHB. In these combinations, respiratory arrest may occur. Respiratory arrest is the absence of breathing. It can result from respiratory distress, respiratory failure, or other events including acute head injury or drowning.


    Emergency medical assistance should be sought when someone becomes unresponsive after taking drugs.


    To reduce the risk of overdosing on flunitrazepam, carefully monitoring of how much has been consumed is advisable. Starting with a small dose and seeing how you feel can prevent you from taking too much all at once. It is advisable to have someone trustworthy around when taking flunitrazepam so that they can help if negative effects are experienced. It is also possible to buy reagent test kits which can confirm or rule out the presence of flunitrazepam. This can also be useful to test a drink that you suspect may have been spiked with the drug.


    Flunitrazepam decreases control and impairs judgment, meaning activities like driving under the influence of flunitrazepam is very dangerous.

  • The risk of respiratory arrest or reduced breathing rate caused by flunitrazepam are increased in people with conditions such as muscle weakness, sleep apnoea, or lung disease/breathing disorders.


    Taking flunitrazepam regularly may put someone at a greater risk of accidents. Doctors in countries where flunitrazepam is prescribed make a considered decision before prescribing it to people with impaired balance and coordination, who are at risk of falling or who may be severely injured if they do.

  • Taking flunitrazepam with other drugs increases the risks. Most notably, the risk of respiratory arrest/.


    Additionally, the effects of flunitrazepam may be masked if taken with a stimulant. This can lead to overdose when the effects of a short acting stimulant, such as cocaine, wear off if the user consumes more flunitrazepam due to not initially being able to feel the effects.

  • One-off or occasional use of flunitrazepam is unlikely to result in the development of addiction.However, taking flunitrazepam regularly over a sustained period can cause very serious psychological addiction.


    Dependency also leads people to experience withdrawal symptoms which include nausea, confusion, headaches, anxiety, and dizziness. Users may crave the drug and feel unable to cope without it. People who regularly use flunitrazepam may become tolerant to the drug’s effects and to the effects of other benzodiazepines/Z drugs, leading them to take increasingly higher doses. The longer the drug is taken and the higher and more regular the dose, the higher the risk of developing dependence and tolerance.

  • A period of sustained use of flunitrazepam can be debilitating and prevent people from working and leading an active life. It may also cause mental and physical harm and withdrawal can be very unpleasant.


    Long term use of flunitrazepam may be accompanied with the use of other drugs, such as alcohol and opioids. This is because some users may feel that flunitrazepam enhances the effects of another drug, or to lessen the effects of drug withdrawal/comedown, or both.


    Acute withdrawal effects include anxiety, increased heart rate and blood pressure, shaking, insomnia and sensitivity to sound/light. Very severe withdrawal can cause symptoms that require intensive care, such as seizures. Someone who has been taking flunitrazepam regularly for a sustained period should only stop under the supervision and guidance of a doctor. Abruptly stopping use can be harmful so it is often better to taper use gradually before stopping entirely. To do this safely, professional advice is recommended.


    Potential effects of long-term flunitrazepam use include anxiety, depression, and insomnia. These effects may last for months, depending on how dependent a person was on the drug, the length of time used, untreated on-going psychiatric conditions, as well as other personal factors such as why the drug was initially prescribed or used illicitly.

  • There are possible harms of long-term flunitrazepam use, although not everyone experiences problems with long term use. Specific harms that could be caused by long term use include lack of energy, sleep problems, impaired memory, and changes in personality (becoming more aggressive, for example). Long term flunitrazepam use is also associated with anxiety related mental health problems such as panic disorder or social phobia. This may be because long term use causes the brain and body to become reliant on the drug’s anxiety-relieving effects. It may therefore be particularly risky for people with depression/anxiety disorders to take flunitrazepam long term.

  • How much are you taking, how often?

    The occasional recreational use of flunitrazepam has a relatively low risk of harm. However, flunitrazepam addiction and dependence can develop after a few weeks of use and can cause considerable harm to quality of life and health. If you develop tolerance to any of the effects of flunitrazepam, this should be taken as a warning sign that the drug may be harmfully affecting your body and brain.


    Are you taking it with anything else? Mixing drugs is risky.

    Drug effects are unpredictable, but mixing drugs makes the effects on your body and mind even harder to control. Deaths involving flunitrazepam generally involve other drugs too. It is particularly dangerous to combine flunitrazepam with another drug that can depress the central nervous system such as alcohol, heroin (or any opioid) or gamma-hydroxybutyrate (GHB). Additionally, if someone is taking antidepressants or even antihistamines, these may increase the effect of the flunitrazepam.

Support our work and help ensure that evidence-based research can influence policy and public opinion, not political or commercial agenda.

Drug Science is an independent, science-led drugs charity. We rely on donations to continue to promote evidence-based information about drugs without political or commercial interference.

We are grateful … But we need more. We can’t do it alone. Becoming a donor will help ensure we can continue our work. Join our Community and access opportunities to become more deeply engaged in our work.

bottom of page