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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
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
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