No reaction
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WARNINGMIXING OR WITHDRAWAL CAN BE DANGEROUS
Ordinary doses in combination with other depressants can fatally stop breathing. After prolonged dependency, stopping suddenly can also cause seizures or delirium; seek medical help.
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Nimetazepam
1-Methylnitrazepam
Erimin, Erimin-5, Happy 5, Lavol, Ro 5-3453
Dosage & Duration
Dosage
Doses are population estimates that vary widely between individuals.
Threshold~2.5 mg
Light2.5-5 mg
Moderate5-10 mg
Strong10-20 mg
Heavy20+ mg
Duration
Onset15-30 minutes
After Effects12-24 hours
Total5-8 hours
Subjective Effects
Subjective Effects not written up yet
Pharmacology
Pharmacology not written up yet
Dangerous
Highest riskThese combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.
Unsafe
AvoidThere is considerable risk of physical harm when taking these combinations, they should be avoided where possible.
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
Tolerance
Tolerance not written up yet
Harm Potential
Addiction & Dependence
Psychological
HighMisuse and dependence are described in both patients and non-medical users, with a strong abuse reputation, declining prescriptions due to rampant misuse and addiction, and significant regional abuse.
Physical
HighNimetazepam physical dependence and withdrawal syndrome add to its addictive nature.
Toxicity
Lethal Dosage
Nimetazepam should not be combined with other CNS depressants. No lethal dose or LD50 value is identified.
Reproductive and developmental
Rat studies reported greater fetal damage than some other benzodiazepines at 100 mg/kg and testicular degenerative changes at high doses.
Hepatic and adrenal
Rat studies reported slight enlargement of the liver and adrenals in high-dose groups.
History & Culture
History & Culture not written up yet
Legality
International
Controlled internationally under the UN Convention on Psychotropic Substances 1971.
By Country
Illegal1
Hong KongIllegalDangerous Drugs Ordinance (Cap. 134), First Schedule, Part I1
Nimetazepam is listed by exact name in Part I of the First Schedule to the Dangerous Drugs Ordinance (Cap. 134) as a dangerous drug. The Ordinance prohibits trafficking and unauthorized supply, unlicensed manufacture, and unauthorized possession or consumption; trafficking includes import and export. Licensing and medical-authority exceptions apply to authorized handling.
Controlled / restricted1
United Statescategorized Schedule IV FDA and DEAPrescription1
SingaporePrescription onlyMisuse of Drugs Act 1973, First Schedule, Part 3; Misuse of Drugs Regulations, regulations 6 to 12 and Second Schedule234
Nimetazepam is listed by name as a Class C drug in Part 3 of the First Schedule to the Misuse of Drugs Act 1973; the listing also covers its stereoisomeric forms, salts, and preparations or products containing it. The Misuse of Drugs Regulations list nimetazepam in the Second Schedule and permit its administration by a medical practitioner, dentist, or collaborative prescribing practitioner, or under such a practitioner's direction. A patient may possess it for medical, dental, or veterinary administration in accordance with a practitioner's directions, and prescriptions are subject to controlled-drug form, validity, authentication, dispensing, and retention requirements.
References
Source Pages
Citations
- Department of Justice, Hong Kong e-Legislation — Cap. 134 Dangerous Drugs Ordinance (current English XML, 12 June 2026). resource.data.one.gov.hk (n.d.). https://resource.data.one.gov.hk/doj/data/hkel_c_leg_cap_1_cap_300_en.zip1
- Misuse of Drugs Act 1973 — First Schedule, Part 3 (Class C Drugs). sso.agc.gov.sg (n.d.). https://sso.agc.gov.sg/Act/MDA1973?Phrase=class%20c&ProvIds=Sc1-&ViewType=Within&WiAl=11
- Misuse of Drugs Regulations — regulations 6 to 12 and Second Schedule. sso.agc.gov.sg (n.d.). https://sso.agc.gov.sg/SL/MDA1973-RG1?WholeDoc=11
- Nimetazepam | Central Narcotics Bureau. cnb.gov.sg (n.d.). https://www.cnb.gov.sg/singapore-drug-situation/drugs--psychoactive-substances--and-inhalants/nimetazepam/1
Further Reading
Article Status
Step 1 · Automated synthesisAn autonomous workflow built by Josie Kins compiled this article's foundation from information published across the web.
- Step 2 · First-pass reviewPending
Not yet reviewed — this article is pending editorial review by Lyrea.
- Step 3 · Citation reviewPending
No one has reviewed this article's citations yet. That second pass checks each claim against the source it cites.
Recent changes7 human edits · latest
Times are UTCNewest first
24 January 2026
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
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