Swimmingdancer said:
I believe you, that just seems so weird to me. If codeine is a pro-drug, how can it kick in faster and be stronger when IM'd? Codeine itself must be active, so you would be getting far less morphine and codeine-6-glucuronide, and slower metabolization to those metabolites, but the effects would be mainly from the codeine itself?
Codeine's bioavailability is about 50-60%. AFAIK almost all of that is codeine-6-glucuronide. Codeine-6-glucuronide is about 60% as strong an analgesic as codeine in rats, not sure about humans. Some have theorized that codeine-6-glucuronide gives a decent amount, perhaps most of the analgesic effects. Others have found that poor metabolizers and those on drugs that block CYP2D6 get more side effects and much less analgesia.
It could be that more codeine is available for conversion to morphine. The enzymes are found in the blood and other organs, not just the liver and GI tracts. Also sometimes changing the ROA can have dramatically different effects. Morphine is stronger than heroin intrathecally, as well as very long acting, like 12 hours. Methadone is twice as strong IV as PO. With methadone IV gives higher brain concentrations whereas PO gives higher liver/GI concentrations.SC/IM methadone are rather unpredictable. Methamphetamine is much stronger IV/smoked than PO, even though it has excellent bioavailability. Also a "button"(bootleg mandrax, methaqualone) has good PO bioavailability, but one 200-400mg pill can give up to 16, knock you on your ass, "OMG I'm high" hits. With IV methaqualone a hypnotic dose, 300mg, give surgical anesthesia for 15 minutes. 20mg of PCP IV with produce general anesthesia, but a similar dose snorted, PO, and slowly smoked with get you really high but somewhat conscious; it too has good PO bioavailability.
Also the codeine itself is active. Not very strong but does something. Someone said in Turkey it's common to IV OTC codeine tablets. They said it has a very strong but really dirty rush. I do not recommend IV due to toxicity. Hopheads(opium smokers) actually prefer opium with a high codeine content over one with a higher morphine content. Then you have lean blunts. I've had opiate users swear up and down that lean blunts do produce an opiate effect. Not strong but noticeable. I tried it but the blunt was poorly rolled and ripped apart. It did seem to do something but didn't try enough to tell. At the very least it makes the blunt burn slower.
dais said:
codeine-6-glucuronide is thought to be mainly responsible for the euphoria created. the morphine is responsible for analgesia.
I've never heard or read that. I've read some stuff that says it might have analgesic effects but nothing on euphoria. I'd be very surprised if it was more euphoric than morphine itself. Do you have something that says that?
i disgaree it's a weak painkiller, well, for those who are extensive metabolisers or who have no problems with metabolsing it.
It's weak but it's on the second step of the WHO's pain management ladder, after NSAIDs have failed. I agree that it's a good pain reliever, especially compared to tramadol(seizures) and darvon(heart problems). But it's side effect/effectiveness profile is good up to 60mg IR, after that it has worse side effects. For something like cancer they may need something stronger, because they may have a short time left in this world. They should be as pain-free as possible. Although codeine is a good starter drug and is often adequate.
doctors have a responsibility of care and starting out on codeine is perfectly acceptable for starting with, especially in today's world where the heavier narcotics are being clamped down on.
This is true, codeine should be tried first. But if it doesn't work something else should be used. However in the US hydrocodone's generally preferred. It's good too.
It's really sad how in most of the world most people will die in pain due to lopsided drug treaties favoring western nations and pharma, backwards views on pain(often from religion), and laws limiting production and distribution of opiates. Most die getting only ibuprofen or Ultram at the very best. It's not due to cost, legit morphine's cheap as fuck. It's due to the "War On Drugs"(TM).