BioAvailibility/Half Life MEGA Thread
BioAvailability/Half-Life MEGA Thread
Lyserg's original post:
All bioavailabilies are relative to IV bioavailability (100% ). For those that do not know, the bioavailability of a substance is basically the percentage of the dose that gets absorbed. It changes drastically for each method of administration. A half-life is the amount of time it takes for your body to eliminate half of the substance that you took. There is a lot of conflicting data on the exact bioavailabilities of each substance so every thing thats listed here is the average.
Opiates
Methadone-oral 84%, halflife- 24-36 hours,
Ketobemiodonel oral was 34% +/-10%, rectally 44% +/- 9%, half-life is 2.25- 2.45 hours
Meperidine rectal bioavailability is approximately 55%, 80% to 85% IM, elimination half-life 3.0 h
Buprenorphine highly protein bound 96%, sublingual bioavailability is approximately 30%, oral is 22%, 90-100% IM, elimination half-life is 12-44 hours
Hydromorphone-- 5-8 times as potent as morphine, intranasal- 52.4%, Rectal administration 33% ,Oral-30-35%,
Dihydrocodeine oral-20% halflife 4 hours
Heroin oral ~35% IV- 100% IM-85% Semisynthetic derivative
Fentanyl- Bioavailability 92% (transdermal), 50% (sublingual/ buccal (against cheek), Protein binding 80-85%, half-life 3-12 hours
Sufentanil intranasal bio- 78%,
Remifentanil Protein binding 70% (bound to plasma proteins) Half life 1-20 minutes
Alfentanil- IV ~100%, 92% protein binding, half life is 1.5-2 hours
Morphine ~30% oral/rectal, insuffulated- 15-20%, Chitosan(a linear polysaccharide that helps absorb drugs better) has been shown to increase nasal bioavailability of morphine from around 10-20% to over 60%, SC-60%, protein binding 30-40%, half-life is 2-3 hours
Oxycodone-oral 60-87% intranasal- 55-70%
Hydrocodone- oral bioavailability is not really known but it is around
oxycodone bioavailability, ~70% of it is usually absorbed, half-life is 4-8 hours
Oxymorphone nasal bioavailabilty [43%] orals low 10-20%
BUTORPHANOL -oral 5-17% due to high first pass metabolism
Tramadol- the absolute bioavailability of rectally admistered tramadol in the suppositories was 77.0%, Oral-68-72% (Increases with repeated dosing) Half life 5-7 hours
Codeine- following rectal or oral administration with a systemic availability of about 90%; in one study clearance varied 4-fold and systemic availability after oral dosage was between 50 and 84%
Diphenoxylate Protein binding 74-95% Half life 12-14 hours used for diarrhea, (does not appreciably cross the blood-brain barrier)
Pethidine(meperidine) Absorption Oral bioavailability is 50-60% in patients with normal hepatic function. Protein Binding 65-75%, Half Life 3-5 hours
Normeperidine is about half as potent as meperidine, but it has twice the CNS stimulation effects.
Pentazocine- Bioavailability ~20% orally, Half-life 2 to 3 hours
Opiate Antagonists
Naloxone oral- 2-4% (90% absorption but high first-pass metabolism), Half life 1-1.5 hours
Naltrexone Oral Bioavailability 5-40%, Protein binding 21%, Half life-4 hours (naltrexone),
and 13 hours (6-β-naltrexol) (metabolite)
Benzodiazepines
Alprazolam- 80-90% oral halflife 9-20 hours
Bromazepam- oral 84% half life 10-20 hours
Cinolazepam- Bioavailability 90-100%, Half life 9 hours
Clobazam-oral 90% 18 hour half life
Clorazepate-oral 91% halflife-36-100 hours
Chlordiazepoxide Oral bioavailability-100% IM-90-95% half-lives of its metabolites range from 14—100 hours
Clonazepam-oral 90% IM- 93%
Diazepam oral bioavailability:85-100%, Protein binding: 94% to 99%
Estazolam-oral 93% half life 10-24 hours
Lorazepam: 78% intranasal, 85-90% oral
Midazolam oral 36-40%, nasal 55%, IM 90%+,
Flurazepam-oral 83% halflife is 40-250 hours
Temazepam-oral 96% halflife is 8-20 hours
Quazepam- Bioavailability 29-35% Half life 39 hours
Other GABA acting drugs/ analogs
Gabapentin (Neurontin)- oral- lower doses absorb better- 60%for .9g daily to 27% for 4.8g daily dose, food increases absorbtion by 14%, Protein binding ~3% Half life 5-7 hours
Pregablin (Lyrica)- Bioavailability ≥90% Half life 5–6.5 hours
Vigabatrin- an anticonvulsant but not a receptor agonist, Bioavailability 80-90% Half life 5-8 hours in young adults, 12-13 hours in the elderly.
Buspirone An anxiolytic that doesnt work on gaba but doesnt really have a category of
its own, Bioavailability (approx. 5% ) due to high first pass metabolism, Half life 2-3h
Stimulants
Methylphenidate 11–52% (Oral); rectal is significantly higher, Half life 2–4 hours
Cocaine hcl 30% oral; 40-60% Nasal Half life .8-4 hours (depending on MOA)
Methamphetamine 79% nasal; 90.3% smoked; 62.7% oral; 100% IV
Amphetamine Oral Bioavailability- 4L/kg; low binding to plasma proteins 20% Halflife 10–13 hours
Ephedrine Bioavailability 85% (oral), Half life 3–6 hours
Dextroamphetamine Oral 75%, half-life 10-28 hours
Bupropron (Wellbrutrin)- Oral- 5-30%, half-life is 20 hours
Dissociatives/psychedelics
PCP- The plasma binding of is 65% orally, smoked is 50%
Ketamine's bioavailability following an intramuscular dose is 93%, intranasal dose 25-50%, IV dose 96% and oral dose 20±7%. Ketamine is rapidly distributed into brain and other highly perfused tissues, and is 12% bound in plasma. The plasma half-life is 2.3 ± 0.5 hours.
MDMA halflife of the "S" isomer has a shorter half life (about 4 hours), whereas the "R" isomer has a much greater half life. (about 14hours)
Anti-depressants
Tianeptine- Bioavailability 89 +/- 11%, Half life 2.5 hours
Trazodone-is 89 to 95% protein bound in vitro at concentrations attained with therapeutic doses.
Muscle relaxants
Carisoprodol(soma)-oral 65%, 60% protein binding, half-life 8 hours
Meprobromate-oral 60% protein binding, half-life is 10 hours
Baclofen-Protein binding 30% Half life 1.5 hours
Dantrolene- Oral ~70%
Sleep aids
Zolpidem is absorbed readily from the gastrointestinal tract. First-pass hepatic metabolism results in an oral bioavailability of 67%, and 92% is bound in plasma
Zaleplon has an oral bioavailability of 30% and has a shorter half-life (1.1 hours) compared to zolpidem.
Diphenhydramine- Bioavailability 86%,Protein binding 98 to 99% Half life 1-4 hours
Eszopiclone (Lunesta)- Protein binding 52-59%, Half life 6 hours
Zopiclone- Bioavailability 52-59% bound to plasma protein, Half life ~6 hours, ~9 hours for over 65
Barbituates
Hexobarbital- ~25% protein binding
Methohexital- I.V. ~100%, Rectal ~17%, half-life is 5.6 hours
Phenobarbital- ~95%, protein binding 20-45%, half-life is 53 to 118 hours
Primidone- oral >90%, protein binding ~70%, half-life of Primidone- 5-15 hours, active metabolite (Phenobarbital) half-life- 100 hours
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JasonCrest's Benzo info:
BENZODIAZEPINES:
Routes of administration:
-
Orally
All benzodiazepines can be taken orally, and have a great bioavailabilty this way.
(exemple: Diazepam oral bioavailability:85-100%, Protein binding: 94% to 99% )
-
Rectally
All benzodiazepines except
Chlordiazepoxide,
Clorazepate (and surely
Loflazepate too) can be taken rectally, and have a great bioavailabilty this way.
-
Intranasal (snorted)
Only the following water-soluble benzos can be effectively snorted:
Flurazepam,
Midazolam,
Loprazolam.
-
Injection (IV/IM)
Unless you have ampoules for injection, only the following benzodiazepines can be prepared for injection with water only:
Flurazepam,
Midazolam,
Loprazolam.
*Note on
Loprazolam: it is not completely soluble, but water-soluble enough to be effective when snorted or injected; this is also because you need a low dosage (1mg).
*Note on the inactive water-soluble benzodiazepines:
Chlordiazepoxide,
Clorazepate Dipotassium (and
Ethyl Loflazepate too I think) are water soluble, but they are inactive benzos, and need to be metabolized by some enzymes in your stomach into active benzos to give an effect. So these benzos can only be taken orally.
If injectable preparations of Clorazepate exist, it's because they contain a substance that makes the Clorazepate active.
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BollWeevil's Post:
dihydrocodeine 21% oral;
methadone 80% oral/ nasal;
76% rectal;
morphine 20-32% oral/
rectal;
10% nasal (non chitosan solution) 10% nasal (non chitosan solution) (2)
hydromorphone 50.7% +/- 29.8% oral; 33% +/- 22% rectal;
54.4% - 59.8% nasal
heroin 
5% oral;
52% smoked
codeine 90% oral; 90% rectal
oxycodone 60 - 87% oral;
45% nasal,
50 - 60% nasal (2),
46% (25–67% ) nasal (3);
widely varies nasally (notes on 50 - 60% study);
rectal the same as oral
bupenorphine 15% oral;
31% sublingual; 90- 100% IM
meperidine 80% to 85% IM
cocaine 30% oral;
30-60% Nasal 57% Nasal (2);
~71% smoked
methylphenidate 11–52% (Oral); rectal is higher, but can't find a source
methamphetamine 79% nasal;
90.3% smoked;
62.7% oral;
"67% of the estimated delivered dose or 37.4% of the absolute (pipe) dose after smoking. "
dextroamphetamine ~25% oral
alprazolam 80-90% oral
diazepam 90% oral/[URL="http://www.springerlink.com/content/acrq1nluwc10bj4w/fulltext.html#N1942"]rectal[/URL]
clonazepam 90% oral
lorazepam 90% oral;
77.7% nasal;
80% rectal
midazolam 75% oral; 55% nasal; 80 - 100% IM
phenobarbital 70-90% oral;
90% rectal
EDIT- If anyone disputes any of these that I didn't link to, let me know and I'll find the source. There shouldn't be any that are unbelievable though.
Click here for the full thread...
![:\](https://bluelight.org/xf/BL_Images/Orig_Emoji/wrygrin.gif "wry grin :\")