Separating Myth from Fact: Naltrexone effective time and re-dosing

Recently, there has been a lot of confusion about the effective time period for a standard dose of naltrexone and we want to set the record straight. We’ve noticed an increased amount of misinformation that is not based on the existing body of research or knowledge of this medication. Further clouding the situation, C Three Foundation CEO Claudia Christian accidentally misspoke in an video interview and her words led some to improperly believe (and then assert as fact) that naltrexone is completely flushed from the system after six hours. (It’s not.)

Below is Claudia’s statement, mildly edited for format, structure, and punctuation.

Statement from Claudia Christian:

I’m sorry for any confusion about dosing. I have had many discussions with doctors over the years. Some have stated that a patient has to take a dose of naltrexone every 4 hours, and some have said 8 hours is fine. Dr. Sinclair told me personally that I would be “safe” for 10 hours after taking a 50mg dose. My own doctor advises people to re-dose “as per needed.”

Clearly this has led to some confusion, including my own personal confusion. It’s difficult when you Google it and this comes up for example for the brand Revia:

“REVIA is a pure opioid receptor antagonist. Although well absorbed orally, naltrexone is subject to significant first pass metabolism with oral bio-availability estimates ranging from 5 to 40%. The activity of naltrexone is believed to be due to both parent and the 6­ ß-naltrexol metabolite. Both parent drug and metabolites are excreted primarily by the kidney (53% to 79% of the dose), however, urinary excretion of unchanged naltrexone accounts for less than 2% of an oral dose and fecal excretion is a minor elimination pathway. The mean elimination half-life (T-1/2) values for naltrexone and 6-ß-naltrexol are 4 hours and 13 hours, respectively. Naltrexone and 6-ß-naltrexol are dose proportional in terms of AUC and Cmax over the range of 50 to 200 mg and do not accumulate after 100 mg daily doses.”

Okay…what the heck does that mean in real life terms?

I have noticed that by taking the middle ground and suggesting people talk to their doctor about taking a second dose 6 hours after the first dose, they seem to respond well. Does that mean that the first dose of naltrexone could have protected them for another hour or two or three? I have no idea.

Everyone’s metabolism is different and (their weight, etc.) Certain factors can influence how long naltrexone stays in the system. One is age. Older people tend to take longer to eliminate drugs from their system compared to younger people. A patient’s overall health and any chronic illnesses can also influence how long naltrexone stays in the system. People with a faster metabolism will eliminate naltrexone more quickly than someone with a slower metabolism. Other individual factors that influence how long naltrexone stays in the system can include body mass and hydration level. The average eliminate half-life of naltrexone is between 4 hours and 13 hours.

All of that said and debated comes down to this: What works for you? When you take one dose and have a few drinks? When you take a dose every 8 hours if you’re going to have a weekend that involves both lunch and dinner imbibing? I can’t tell you that.

Your doctor can advise you on what they feel is “right” but at the end of the day it comes down to you to figure out how you metabolize naltrexone, when you “feel” it is out of your system, and when you feel vulnerable to heavy drinking experiences.

I hope this helps clarify the dosage questions and allows you the freedom to customize your own recovery with your doctor’s support. If you feel that a second dose is helping you then you must speak to your doctor to ensure that you have an adequate supply of medication.



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