Two to Three
How Does Heroin Compare to Morphine?
It is often reported that heroin is "two to three times as powerful as morphine." But most research is based upon intramuscular injections. The standard numbers are that it takes 5 mg of heroin to relieve as much pain as 10 mg of morphine when both are administered intramuscularly. Orally, the numbers are 40 mg of heroin and 60 mg of morphine.
These numbers prove the point of the main article: the longer it takes heroin to get to the brain, the more it acts just like morphine. Administered intramuscularly--hardly a very direct means of ingestion for a drug destined for the brain--heroin is 200% as effective as morphine. Administered orally, heroin is only 150% as effective.
The numbers indicate that a lot of morphine is destroyed when it is ingested orally. One needs to ingest six times as much orally as one does when IM injecting. Surprisingly, codeine is quite efficient taken orally--almost 70% as effective as IM injection.
But if heroin is turned into morphine as quickly as stated in the main article, isn't it reasonable to assume that heroin administered intravenously would be even more potent compared to morphine? The answer is: yes. This is where the "two to three" number comes in. IV heroin is believed to be three times as powerful as IV morphine. It may be even more powerful.
This fact should be taken into account when you are attempting to detox yourself using some kind of opioid substitution. In matching doses, a higher potency for heroin should be assumed if it is being administered directly to a vein. On the other hand, a lower potency should be assumed if it is being ingested in a less direct way like inhalation.