Nitrous oxide


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Nitrous oxide
Accession Number
Small Molecule
Approved, Vet approved

Nitrous oxide, commonly known as "laughing gas", is a chemical compound with the chemical formula N2O. At room temperature, it is a colorless non-flammable gas, with a pleasant, slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic effects. It is known as "laughing gas" due to the euphoric effects of inhaling it, a property that has led to its recreational use as an inhalant drug.

  • N2O
  • Nitrious oxide
  • óxido nitroso
External IDs
E-942 / FEMA NO. 2779 / INS NO.942 / INS-942
Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing End
Nitrous OxideGas99 L/100LRespiratory (inhalation)Compressed Gases Inc1980-01-01Not applicableUs
Nitrous OxideGas99 L/100LRespiratory (inhalation)Air Liquide America Specialty Gases LLC1960-01-012016-09-09Us
Nitrous OxideGas99 L/100LRespiratory (inhalation)Volunteer Welding Supply Inc1973-01-01Not applicableUs
Nitrous OxideGas99 L/100LRespiratory (inhalation)Air Source Industries1992-01-01Not applicableUs
Nitrous OxideGas990 mL/1LRespiratory (inhalation)Airgas East, Inc.1991-01-15Not applicableUs
Nitrous OxideGas990 mL/1LRespiratory (inhalation)Roberts Oxygen Company, Inc.1967-01-01Not applicableUs
Nitrous OxideGas990 mL/1LRespiratory (inhalation)Aero All Gas Company1972-10-06Not applicableUs
Nitrous OxideGas99 L/100LRespiratory (inhalation)Linde Gas North America LLC1990-11-27Not applicableUs
Nitrous OxideGas99 L/100LRespiratory (inhalation)Indianapolis Welding Supply, Inc1972-01-012013-04-12Us
Nitrous OxideGas99 L/100LRespiratory (inhalation)Blue Water Industrial Products, Inc.2008-12-01Not applicableUs
Additional Data Available
  • Application Number
    Application Number

    A unique ID assigned by the FDA when a product is submitted for approval by the labeller.

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  • Product Code
    Product Code

    A governmentally-recognized ID which uniquely identifies the product within its regulatory market.

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Mixture Products
NameIngredientsDosageRouteLabellerMarketing StartMarketing End
Alnox GasNitrous oxide (50 %) + Oxygen (50 %)GasRespiratory (inhalation)Air Liquide Canada Inc.1995-12-31Not applicableCanada
EntonoxNitrous oxide (50 %) + Oxygen (50 %)GasRespiratory (inhalation)Linde Llc1995-12-31Not applicableCanada
Liqui-med Analgesic GasNitrous oxide (50 %) + Oxygen (50 %)GasRespiratory (inhalation)Praxair, Inc.1983-12-31Not applicableCanada
Nitrous Oxide In OxygenNitrous oxide (50 %) + Oxygen (50 %)GasRespiratory (inhalation)Matheson Gas Products Canada Inc.1982-12-311997-12-24Canada
Unapproved/Other Products
NameIngredientsDosageRouteLabellerMarketing StartMarketing End
Nitrous OxideNitrous oxide (990 mL/1L)GasRespiratory (inhalation)Airgas East, Inc.1991-01-15Not applicableUs
Nitrous OxideNitrous oxide (990 mL/1L)GasRectalEncompass Medical & Specialty Gases, Ltd.2008-01-02Not applicableUs
Nitrous OxideNitrous oxide (992 mL/1L)GasRespiratory (inhalation)Airgas West, Inc.1947-05-23Not applicableUs
Nitrous OxideNitrous oxide (99 kg/100kg)GasRespiratory (inhalation)Specialty Gases Of America1995-01-012015-06-10Us
Nitrous OxideNitrous oxide (99.5 L/100L)GasRespiratory (inhalation)Air Liquide Canada Inc.1960-01-012010-05-20Us
Nitrous OxideNitrous oxide (99 L/100L)LiquidRespiratory (inhalation)Welding & Therapy Service, Inc1971-11-01Not applicableUs
Nitrous OxideNitrous oxide (99 L/100L)GasRespiratory (inhalation)Argyle Welding Supply Company, Inc.1974-01-01Not applicableUs
Nitrous OxideNitrous oxide (992 mL/1L)GasRespiratory (inhalation)Airgas Intermountain Inc1985-01-01Not applicableUs
Nitrous OxideNitrous oxide (99 L/100L)GasRespiratory (inhalation)Compressed Gases Inc1980-01-01Not applicableUs
Nitrous OxideNitrous oxide (992 mL/1L)GasRespiratory (inhalation)Airgas Mid South, Inc1997-11-062010-08-06Us
CAS number
Average: 44.0128
Monoisotopic: 44.001062632
Chemical Formula
InChI Key


Not Available
Associated Therapies
Not Available
Mechanism of action

Findings to date indicate that nitrous oxide induces opioid peptide release in the brain stem leading to the activation of descending noradrenergic neurones, which results in modulation of the nociceptive process in the spinal cord. Several receptor–effector mechanisms including dopamine receptors, α2 adrenoceptors, benzodiazepine receptors and -methyl- -aspartate (NMDA) receptors have been implicated although the relationship of one with the other is not known.

Additional Data Available
Adverse Effects

Comprehensive structured data on known drug adverse effects with statistical prevalence. MedDRA and ICD10 ids are provided for adverse effect conditions and symptoms.

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Additional Data Available

Structured data covering drug contraindications. Each contraindication describes a scenario in which the drug is not to be used. Includes restrictions on co-administration, contraindicated populations, and more.

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Blackbox Warnings

Structured data representing warnings from the black box section of drug labels. These warnings cover important and dangerous risks, contraindications, or adverse effects.

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Not Available
Volume of distribution
Not Available
Protein binding
Not Available
Not Available
Route of elimination
Not Available
Half life
Not Available
Not Available
Not Available
Affected organisms
Not Available
Not Available
Pharmacogenomic Effects/ADRs
Not Available


Drug Interactions
1-(3-Mercapto-2-Methyl-Propionyl)-Pyrrolidine-2-Carboxylic AcidThe risk or severity of hypertension can be increased when 1-(3-Mercapto-2-Methyl-Propionyl)-Pyrrolidine-2-Carboxylic Acid is combined with Nitrous oxide.
1-benzylimidazoleThe risk or severity of hypertension can be increased when 1-benzylimidazole is combined with Nitrous oxide.
2,5-Dimethoxy-4-ethylamphetamineThe risk or severity of hypertension can be increased when 2,5-Dimethoxy-4-ethylamphetamine is combined with Nitrous oxide.
2,5-Dimethoxy-4-ethylthioamphetamineThe risk or severity of adverse effects can be increased when Nitrous oxide is combined with 2,5-Dimethoxy-4-ethylthioamphetamine.
4-Bromo-2,5-dimethoxyamphetamineThe risk or severity of adverse effects can be increased when 4-Bromo-2,5-dimethoxyamphetamine is combined with Nitrous oxide.
4-MethoxyamphetamineThe risk or severity of adverse effects can be increased when 4-Methoxyamphetamine is combined with Nitrous oxide.
5-methoxy-N,N-dimethyltryptamineThe risk or severity of adverse effects can be increased when Nitrous oxide is combined with 5-methoxy-N,N-dimethyltryptamine.
7-NitroindazoleThe risk or severity of adverse effects can be increased when 7-Nitroindazole is combined with Nitrous oxide.
7,8-Dichloro-1,2,3,4-tetrahydroisoquinolineThe risk or severity of adverse effects can be increased when Nitrous oxide is combined with 7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline.
AbediterolThe risk or severity of hypertension can be increased when Nitrous oxide is combined with Abediterol.
Additional Data Available
  • Extended Description
    Extended Description

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  • Severity

    A severity rating for each drug interaction, from minor to major.

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  • Evidence Level
    Evidence Level

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  • Action

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Food Interactions
Not Available


General References
Not Available
External Links
Human Metabolome Database
KEGG Compound
PubChem Compound
PubChem Substance
ATC Codes
N01AX13 — Nitrous oxideN01AX63 — Nitrous oxide, combinations
AHFS Codes
  • 28:04.16 — Inhalation Anesthetics
PDB Entries
2icq / 2ie7 / 2ppa / 3pk3 / 3pks / 3pkt / 3pku / 3ple / 3plg / 3plh
show 7 more

Clinical Trials

Clinical Trials
0CompletedTreatmentAnxiety Disease1
0TerminatedTreatmentBipolar Depressive Disorder / Bipolar Disorder (BD) / Treatment- Resistant Bipolar Disorder1
1Active Not RecruitingBasic ScienceHealthy Volunteers1
1Enrolling by InvitationTreatmentDepression / Major Depressive Disorder (MDD) / Moods Disorders / Suicidal Thoughts1
1RecruitingTreatmentDepressive Disorder, Treatment-Resistant / Major Depressive Disorder (MDD)1
1TerminatedTreatmentPeripheral Vein Vasodilation1
1, 2CompletedHealth Services ResearchAnaesthesia therapy1
2Active Not RecruitingTreatmentDepression / Major Depressive Disorder (MDD)1
2CompletedNot AvailableAlcohol-Related Disorders / Opioid-Related Disorders / Substance-Related Disorders1
2CompletedTreatmentOpioid-Related Disorders / Substance-Related Disorders6
2Not Yet RecruitingTreatmentObsessive Compulsive Disorder (OCD)1
2RecruitingTreatmentBipolar Disorder (BD)1
2RecruitingTreatmentDepression / Depressive Disorders / Major Depressive Disorder (MDD) / Treatment Resistant Depression (TRD)1
2RecruitingTreatmentDepression / Major Depressive Disorder (MDD)1
2RecruitingTreatmentDepressive Disorder, Treatment-Resistant / Major Depressive Disorder (MDD)1
2RecruitingTreatmentPost Traumatic Stress Disorder (PTSD)1
2RecruitingTreatmentSickle Cell Disorders / Vaso-Occlusive Crises1
2TerminatedTreatmentLabour Pain1
2, 3RecruitingTreatmentObstetrical analgesia therapy / Obstetrical Anesthesia / Postpartum Depression1
3CompletedPreventionColorectal Cancers1
3CompletedTreatmentComplications, Pregnancy / Complications; Cesarean Section / Fetus or Neonate Affected by External Version Before Labor / Inhalation of Nitrous Oxide / Non-cephalic Presentation1
3CompletedTreatmentExternal Cephalic Version1
3CompletedTreatmentInjection Site Vesicles1
3Enrolling by InvitationTreatmentComplex Regional Pain Syndrome (CRPS)1
3Not Yet RecruitingTreatmentDehydrated Infants Needing Nasogastric Tube Placement for Rehydration1
3TerminatedPreventionPain NOS1
3Unknown StatusTreatmentFiberoptic Bronchoscopy1
3WithdrawnNot AvailableAnalgesic Affect1
4CompletedNot AvailableAnaesthesia therapy1
4CompletedBasic ScienceAdjunct to general anesthesia therapy / Adverse Effects / Nitrous Oxide1
4CompletedDiagnosticDepth of Anaesthesia1
4CompletedDiagnosticGlaucoma / Sedation therapy1
4CompletedOtherLumbar Punctures / Minor Incision Drainage of Abscesses Not Requiring Extensive Debridement / Sedation, Conscious / Simple Lacerations Less Than 4 cm1
4CompletedPreventionEffects of Nitrous Oxide Following Anaesthesia / Induced Endothelial Dysfunction / Quality of Recovery From Anaesthesia1
4CompletedTreatmentAnaesthesia therapy1
4CompletedTreatmentAnalgesia / Bowel Cancer Screening / Colonoscopy / Entonox1
4CompletedTreatmentFeeling Anxious / Pain NOS1
4CompletedTreatmentPain NOS1
4CompletedTreatmentPulmonary Function Under Anaesthesia1
4Not Yet RecruitingTreatmentSafety and Efficacy of Intranasal Dexmedetomidine1
4RecruitingDiagnosticPain NOS1
4RecruitingTreatmentPatients Requiring Diagnostic Gastroscopy Suitable for Sedation / Patients Requiring Diagnostic Gastroscopy With Sedation1
4SuspendedTreatmentAnaesthesia therapy / Delirium, Dementia, Amnestic, Cognitive Disorders1
4WithdrawnTreatmentAbscesses / Laceration1
Not AvailableActive Not RecruitingSupportive CareAbdominal Hysterectomy (& Wertheim) / Adjunct to general anesthesia therapy / Nitrous Oxide1
Not AvailableCompletedNot AvailableAlcohol-Related Disorders / Opioid-Related Disorders / Substance-Related Disorders1
Not AvailableCompletedNot AvailableAmnesia1
Not AvailableCompletedNot AvailableOpioid-Related Disorders / Substance-Related Disorders7
Not AvailableCompletedDiagnosticCoronary Artery Disease / Major Surgery1
Not AvailableCompletedHealth Services ResearchAdjunct to general anesthesia therapy / Deep Sedation1
Not AvailableCompletedOtherPregnancy Termination in Second Trimester1
Not AvailableCompletedPreventionCardiovascular Abnormalities1
Not AvailableCompletedTreatmentAbscesses / Laceration1
Not AvailableCompletedTreatmentMigraine / Pain NOS1
Not AvailableCompletedTreatmentOpioid-Related Disorders / Substance-Related Disorders1
Not AvailableNot Yet RecruitingTreatmentColonic Neoplasms1
Not AvailableNot Yet RecruitingTreatmentFeeling Anxious1
Not AvailableRecruitingSupportive CareInguinal Herniorrhaphy / Post Operative Pain1
Not AvailableRecruitingTreatmentAbscesses1
Not AvailableRecruitingTreatmentAbscesses / Joint dislocations / Perianal Abscess1
Not AvailableRecruitingTreatmentAdjunct to general anesthesia therapy / Anesthesia Recovery Period / Elective Surgical Procedures / Laparoscopy / Laparotomy1
Not AvailableRecruitingTreatmentLabour Pain1
Not AvailableUnknown StatusBasic SciencePain NOS1
Not AvailableWithdrawnTreatmentLocal Anesthetic Efficacy1


Not Available
Not Available
Dosage forms
GasRespiratory (inhalation)
GasRectal990 mL/1L
GasRespiratory (inhalation)900 mL/1L
GasRespiratory (inhalation)98 %
GasRespiratory (inhalation)99 kg/100kg
GasRespiratory (inhalation)99 mL/1L
GasRespiratory (inhalation)99 mL/100mL
GasRespiratory (inhalation)99 L/100L
GasRespiratory (inhalation)99.5 L/100L
GasRespiratory (inhalation)99.5 L/1L
GasRespiratory (inhalation)990 mL/1L
GasRespiratory (inhalation)992 mL/1L
GasRespiratory (inhalation)995 mL/1L
LiquidRespiratory (inhalation)99 L/100L
GasRespiratory (inhalation)100 %
GasRespiratory (inhalation)99 %
Not Available
Not Available


Experimental Properties
melting point (°C)-90.81 °CPhysProp
boiling point (°C)-88.46 °CPhysProp
logP0.36HANSCH,C ET AL. (1995)
Predicted Properties
pKa (Strongest Basic)-6.8ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count0ChemAxon
Polar Surface Area54.46 Å2ChemAxon
Rotatable Bond Count0ChemAxon
Refractivity27.67 m3·mol-1ChemAxon
Polarizability2.54 Å3ChemAxon
Number of Rings0ChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Predicted ADMET features
Human Intestinal Absorption+0.9467
Blood Brain Barrier+0.9872
Caco-2 permeable+0.5561
P-glycoprotein substrateNon-substrate0.9009
P-glycoprotein inhibitor INon-inhibitor0.9747
P-glycoprotein inhibitor IINon-inhibitor0.9944
Renal organic cation transporterNon-inhibitor0.9407
CYP450 2C9 substrateNon-substrate0.8867
CYP450 2D6 substrateNon-substrate0.8789
CYP450 3A4 substrateNon-substrate0.7447
CYP450 1A2 substrateNon-inhibitor0.7496
CYP450 2C9 inhibitorNon-inhibitor0.9074
CYP450 2D6 inhibitorNon-inhibitor0.9293
CYP450 2C19 inhibitorNon-inhibitor0.9089
CYP450 3A4 inhibitorNon-inhibitor0.9871
CYP450 inhibitory promiscuityLow CYP Inhibitory Promiscuity0.9435
Ames testAMES toxic0.7381
CarcinogenicityCarcinogens 0.6906
BiodegradationReady biodegradable0.9704
Rat acute toxicity2.8320 LD50, mol/kg Not applicable
hERG inhibition (predictor I)Weak inhibitor0.8497
hERG inhibition (predictor II)Non-inhibitor0.971
ADMET data is predicted using admetSAR, a free tool for evaluating chemical ADMET properties. (23092397)


Mass Spec (NIST)
Not Available
SpectrumSpectrum TypeSplash Key
Predicted GC-MS Spectrum - GC-MSPredicted GC-MSNot Available
Predicted MS/MS Spectrum - 10V, Positive (Annotated)Predicted LC-MS/MSsplash10-0002-9000000000-2eee7435817186856ef7
Predicted MS/MS Spectrum - 20V, Positive (Annotated)Predicted LC-MS/MSsplash10-001j-9000000000-d1a5381e3dd214cad7ab
Predicted MS/MS Spectrum - 40V, Positive (Annotated)Predicted LC-MS/MSsplash10-000t-9000000000-3ae2e01e3d626729760b
Predicted MS/MS Spectrum - 10V, Negative (Annotated)Predicted LC-MS/MSsplash10-004l-9000000000-c53ff0d270e0310b3375
Predicted MS/MS Spectrum - 20V, Negative (Annotated)Predicted LC-MS/MSsplash10-004i-9000000000-c8b9d8f80d3f41ad7f54
Predicted MS/MS Spectrum - 40V, Negative (Annotated)Predicted LC-MS/MSsplash10-002f-9000000000-12c3fe456373daff732e


This compound belongs to the class of inorganic compounds known as other non-metal nitrides. These are inorganic compounds of nitrogen where nitrogen has a formal oxidation state of -3, and the heaviest atom bonded to it belongs to the class of 'other non-metals'.
Inorganic compounds
Super Class
Homogeneous non-metal compounds
Other non-metal organides
Sub Class
Other non-metal nitrides
Direct Parent
Other non-metal nitrides
Alternative Parents
Inorganic oxides / Inorganic nitrides
Other non-metal nitride / Inorganic nitride / Inorganic oxide
Molecular Framework
Not Available
External Descriptors
nitrogen oxide (CHEBI:17045) / a non-metabolic compound (NITROUS-OXIDE)

Drug created on September 02, 2008 09:56 / Updated on July 18, 2019 17:28