Triazolam
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4 sources
Collated from TripSit, Pharmacology, DrugCentral, DailyMed. Where sources differ (e.g. dosing), Compare shows them side by side.
Also known as halcionTS
An uncommon and very short acting benzodiazepine. Sedating and hypnotic, and may induce amnesia and lowered inhibitions at high doses.TS
Oral
Route dataTripSit
| Threshold | Light | Common | Strong | Heavy |
|---|---|---|---|---|
| — | 0.125–0.25 mg | 0.25–0.5 mg | 0.5–1.5 mg | —+ |
| Onset | 10–20 minutes |
|---|---|
| After-effects | 1–6 hours |
🧬 Receptor activityPHDC
| Target | Action | Affinity | Source | |
|---|---|---|---|---|
| GABA-A receptor; alpha-2/beta-3/gamma-2 | — | Ki 0.59 nM | CHEMBL | TargetGABA-A receptor; alpha-2/beta-3/gamma-2 Action— AffinityKi 0.59 nM SourceCHEMBL |
| GABA-A receptor; anion channel | — | Ki 0.8 nM | CHEMBL | TargetGABA-A receptor; anion channel Action— AffinityKi 0.8 nM SourceCHEMBL |
| GABA-A receptor; alpha-1/beta-3/gamma-2 | — | Ki 0.8 nM | CHEMBL | TargetGABA-A receptor; alpha-1/beta-3/gamma-2 Action— AffinityKi 0.8 nM SourceCHEMBL |
| GABA-A receptor; alpha-3/beta-3/gamma-2 | — | Ki 1.43 nM | CHEMBL | TargetGABA-A receptor; alpha-3/beta-3/gamma-2 Action— AffinityKi 1.43 nM SourceCHEMBL |
| GABA-A receptor; alpha-5/beta-3/gamma-2 | — | Ki 1.54 nM | CHEMBL | TargetGABA-A receptor; alpha-5/beta-3/gamma-2 Action— AffinityKi 1.54 nM SourceCHEMBL |
| GABA-A receptor; alpha-6/beta-3/gamma-2 | — | Ki 10000 nM | CHEMBL | TargetGABA-A receptor; alpha-6/beta-3/gamma-2 Action— AffinityKi 10000 nM SourceCHEMBL |
| GABA A receptor alpha-3/beta-2/gamma-2 (GABRG2) | Positive allosteric modulator | 8.876 Ki | DRUGCENTRAL | TargetGABA A receptor alpha-3/beta-2/gamma-2 (GABRG2) ActionPositive allosteric modulator Affinity8.876 Ki SourceDRUGCENTRAL |
| GABA A receptor alpha-3/beta-2/gamma-3 (GABRA3) | Positive allosteric modulator | 8.108 Ki | DRUGCENTRAL | TargetGABA A receptor alpha-3/beta-2/gamma-3 (GABRA3) ActionPositive allosteric modulator Affinity8.108 Ki SourceDRUGCENTRAL |
| GABA A receptor alpha-5/beta-2/gamma-2 (GABRG2) | Positive allosteric modulator | 9.222 Ki | DRUGCENTRAL | TargetGABA A receptor alpha-5/beta-2/gamma-2 (GABRG2) ActionPositive allosteric modulator Affinity9.222 Ki SourceDRUGCENTRAL |
| GABA A receptor alpha-5/beta-2/gamma-3 (GABRA5) | Positive allosteric modulator | 8.699 Ki | DRUGCENTRAL | TargetGABA A receptor alpha-5/beta-2/gamma-3 (GABRA5) ActionPositive allosteric modulator Affinity8.699 Ki SourceDRUGCENTRAL |
| GABA A receptor alpha-5/beta-3/gamma-3 (GABRB3) | Positive allosteric modulator | 8.699 Ki | DRUGCENTRAL | TargetGABA A receptor alpha-5/beta-3/gamma-3 (GABRB3) ActionPositive allosteric modulator Affinity8.699 Ki SourceDRUGCENTRAL |
| GABA-A receptor (GABRD) | Positive allosteric modulator | 9.1 Ki | DRUGCENTRAL | TargetGABA-A receptor (GABRD) ActionPositive allosteric modulator Affinity9.1 Ki SourceDRUGCENTRAL |
| GABA-A receptor alpha-1/beta-2/gamma-2 (GABRA1) | Positive allosteric modulator | 9.155 Ki | DRUGCENTRAL | TargetGABA-A receptor alpha-1/beta-2/gamma-2 (GABRA1) ActionPositive allosteric modulator Affinity9.155 Ki SourceDRUGCENTRAL |
| GABA-A receptor alpha-1/beta-2/gamma-3 (GABRA1) | Positive allosteric modulator | 8.638 Ki | DRUGCENTRAL | TargetGABA-A receptor alpha-1/beta-2/gamma-3 (GABRA1) ActionPositive allosteric modulator Affinity8.638 Ki SourceDRUGCENTRAL |
| GABA-A receptor alpha-1/beta-3/gamma-2 (GABRA1) | Positive allosteric modulator | 9.097 Ki | DRUGCENTRAL | TargetGABA-A receptor alpha-1/beta-3/gamma-2 (GABRA1) ActionPositive allosteric modulator Affinity9.097 Ki SourceDRUGCENTRAL |
| GABA-A receptor alpha-2/beta-3/gamma-2 (GABRG2) | Positive allosteric modulator | 9.229 Ki | DRUGCENTRAL | TargetGABA-A receptor alpha-2/beta-3/gamma-2 (GABRG2) ActionPositive allosteric modulator Affinity9.229 Ki SourceDRUGCENTRAL |
| GABA-A receptor alpha-3/beta-3/gamma-2 (GABRG2) | Positive allosteric modulator | 8.845 Ki | DRUGCENTRAL | TargetGABA-A receptor alpha-3/beta-3/gamma-2 (GABRG2) ActionPositive allosteric modulator Affinity8.845 Ki SourceDRUGCENTRAL |
| GABA-A receptor alpha-5/beta-3/gamma-2 (GABRG2) | Positive allosteric modulator | 9.02 Ki | DRUGCENTRAL | TargetGABA-A receptor alpha-5/beta-3/gamma-2 (GABRG2) ActionPositive allosteric modulator Affinity9.02 Ki SourceDRUGCENTRAL |
| Cholecystokinin receptor type A (Cckar) | — | 4.41 IC50 | DRUGCENTRAL | TargetCholecystokinin receptor type A (Cckar) Action— Affinity4.41 IC50 SourceDRUGCENTRAL |
| Cytochrome P450 3A4 (CYP3A4) | — | 4.27 Ki | DRUGCENTRAL | TargetCytochrome P450 3A4 (CYP3A4) Action— Affinity4.27 Ki SourceDRUGCENTRAL |
| GABA-A receptor; anion channel (Gabrp) | — | 9.1 Ki | DRUGCENTRAL | TargetGABA-A receptor; anion channel (Gabrp) Action— Affinity9.1 Ki SourceDRUGCENTRAL |
| Platelet-activating factor receptor (PTAFR) | — | 5.879 Ki | DRUGCENTRAL | TargetPlatelet-activating factor receptor (PTAFR) Action— Affinity5.879 Ki SourceDRUGCENTRAL |
Mechanism of actionPHDM
Benzodiazepines bind nonspecifically to bezodiazepine receptors BNZ1, which mediates sleep, and BNZ2, which affects affects muscle relaxation, anticonvulsant activity, motor coordination, and memory. As benzodiazepine receptors are thought to be coupled to gamma-aminobutyric acid-A (GABA<sub>A</sub>) receptors, this enhances the effects of GABA by increasing GABA affinity for the GABA receptor. Binding of GABA to the site opens the chloride channel, resulting in a hyperpolarized cell membrane that prevents further excitation of the cell.
In animals, benzodiazepines protect against seizures induced by electrical stimulation and by pentylenetetrazol; benzodiazepines appear to act, at least partly, by augmenting presynaptic inhibition. The drugs suppress the spread of seizure activity but do not abolish the abnormal discharge from a focus in experimental models of epilepsy. In usual doses, benzodiazepines appear to have very little effect on the autonomic nervous system, respiration, or the cardiovascular system. /Benzodiazepines/
... /Benzodiazepines/ appear to act at the limbic, thalamic, and hypothalamic levels of the CNS, producing anxiolytic, sedative, hypnotic, skeletal muscle relaxant, and anticonvulsant effects. The effects of benzodiazepines may be mediated through the inhibitory neurotransmitter gamma-aminobutyric acid. Benzodiazepines are capable of producing all levels of CNS depression from mild sedation to hypnosis to coma. /Benzodiazepines/
Anxiolytic and possibly paradoxical CNS stimulatory effects of benzodiazepines are postulated to result from release of previously suppressed responses (disinhibition). After usual doses of benzodiazepines for several days, the drugs cause a moderate decrease in rapid eye movement (REM) sleep. REM rebound does not occur when the drugs are withdrawn. Stage 3 and 4 sleep are markedly reduced by usual doses of the drugs; the clinical importance of these sleep stage alterations has not been established. /Benzodiazepines/
Benzodiazepines appear to produce skeletal muscle relaxation predominantly by inhibiting spinal polysynaptic afferent pathways, but the drugs may also inhibit monosynaptic afferent pathways. The drugs may inhibit monosynaptic and polysynaptic reflexes by acting as inhibitory neuronal transmitters or by blocking exitatory synaptic transmission. The drugs may also directly depress motor nerve and muscle function. /Benzodiazepines/
PharmacodynamicsPH
A short-acting benzodiazepine used as a hypnotic agent in the treatment of insomnia. Some countries temporarily withdrew triazolam from the market because of concerns about adverse reactions, mostly psychological, associated with higher dose ranges. Its use at lower doses with appropriate care and labeling has been reaffirmed by the FDA and most other countries. Triazolam has a shorter half-life than chlordiazepoxide, flurazepam, and prazepam and does not generate active metabolites.
Pharmacokinetics
Half-lifePH
1.5-5.5 hours
It has a biphasic half-life with a reported mean apparent half-life of 3.4 hr for the initial phase and 7.8 hr for the terminal phase.
Elimination half-life for triazolam is 1.6-5.4 hr. /From table/
AbsorptionPH
Bioavailability is 44% (oral) and 53% (sublingual).
Triazolam and its metabolites, principally as conjugated glucuronides, which are presumably inactive, are excreted primarily in the urine. Only small amounts of unmetabolized triazolam appear in the urine. The two primary metabolites accounted for 79.9% of urinary excretion.
Plasma half-life, elimination coefficient, concentration, and apparent volume of distribution were calculated at steady state and mean values were 53 hr, 0.0147/hr, 884 ng/mL, & 1.13 l/kg /respectively/.
Triazolam is rapidly and nearly completely absorbed from the GI tract. It has a biphasic half-life with a reported mean apparent half-life of 3.4 hr for the initial phase and 7.8 hr for the terminal phase. It is reported to be extensively bound to plasma proteins. It is excreted in the urine in the form of its metabolites with only small amounts appearing unchanged.
In a study of triazolam tablets and a liquid formulation in healthy subjects, the bioavailability of the tablets was rapid and, relative to the liquid formulation, complete. The average half-life for absorption was 8 minutes with peak concentrations being achieved an average of 42 minutes after dosing.
It is not known whether triazolam is distributed into milk in humans; however, the drug and its metabolites are distributed into milk in rats.
MetabolismPH
Hepatic. Small amounts of unmetabolized triazolam appear in the urine.
Triazolam undergoes hepatic microsomal oxidation to inactive hydroxylated metabolites that are eliminated primarily as glucuronide conjugates.
Triazolam has known human metabolites that include alpha-Hydroxytriazolam and 4-Hydroxytriazolam.
Hepatic. Small amounts of unmetabolized triazolam appear in the urine. Triazolam undergoes hepatic microsomal oxidation to inactive hydroxylated metabolites that are eliminated primarily as glucuronide conjugates (A630).
Route of Elimination: Triazolam and its metabolites, principally as conjugated glucuronides, which are presumably inactive, are excreted primarily in the urine. Only small amounts of unmetabolized triazolam appear in the urine. The two primary metabolites accounted for 79.9% of urinary excretion.
Half Life: 1.5-5.5 hours
External links
Fact-sheets from PsychonautWiki. Harm-reduction reference only — not medical advice.