Isoprinosine (Imunovir)

IsoprinosineIsoprinosine (inosine pranobex) is..

a prescription drug posited to have immune modulating and anti-viral properties. It’s brand name is Imunovir. A synthetic purine derivative it is a precursor to adenosine which modulates many physiological processes including inflammation.

Isoprinosine’s manufacturer Newport Pharmaceutical reports Isoprinosine is registered for use in over 40 countries to treat a variety of infections including several herpesviruses. Recent studies have examined its effects in subacute sclerosing pancephalitis, a rare brain inflammation caused by a herpes virus (negligible), genital warts (positive), ‘recurrent childhood infections’ (positive) and again subacute sclerosing pancephalits (a larger study – this time positive ).

Studies suggest that isoprinosine may be able to increase natural killer cell functioning, stimulate the production of cytotoxic T-cells, increase the production of the IL-1,IL-2 and IFN-y cytokines, enhance the transition of B-cells into antibody producing plasma cells and helps to ‘turn on’ neutrophils, monocytes and macrophages.

Isoprinosine is not licensed by the FDA and is not available for purchase in the US. Isoprinosine can be purchased online at Rivex Biopharma and Life Extension. Newport Pharmaceuticals is a small pharmaceutical company focused entirely on Isoprinosine. It has been pursuing Isoprinosine as a treatment for chronic fatigue syndrome in the US since 1999. Isoprinosine joins Ampligen and Nexavir in a group of anti-viral and/or immunomodulatoryprescription drugs produced by small pharmaceutical companies that have yet to be licensed in the U.S.

Isoprinosine Could Help in ME/CFS Because…

it appears to enhance the functioning of several parts of the immune system that appear, at least in some patients, to be performing poorly. These include natural killer cells, T-cells, neutrophils and some cytokines.

Chronic Fatigue Syndrome (ME/CFS) Doctors Report

 In 1999 Dr. Byron Hyde reported that a small Isoprinosine study was ‘milestone’ in the treatment of ME/CFS. Dr. Paul Cheney calls Isoprinosine a ‘very good immune-modulator’ and appears to have used it extensively to boost NK cell functioning and reduce Th2 dominance in the immune system. In 2007 Dr. De Meirleir stated that he felt that Inosine – an amino acid available in health food stores – was as effective as Isoprinosine.

Chronic Fatigue Syndrome (ME/CFS) Isoprinosine Studies

Few studies have assessed Isoprinosine’s effectiveness in ME/CFS. After a small single blind, placebo-controlled trial of 16 patients in 1999 Dr.Hyde’s published study (2003) indicated that 6/10 patients improved and that their natural killer cell activity and T-helper cell numbers increased but no changes were seen in IFN-y, IL-1@, IL-10 and IL-12 levels. At the 2009 IACFS/ME conference Dr. Hone reported that Isoprinsine conferred ‘significant (clinical) improvement’ and increased NK cell functioning and reduced Epstein-Barr Virus levels in patients with reduced natural killer cell activity.

Dose –Because of its immunomodulatory properties Dr. Cheney recommends staggering dosages:

First Month:

  • Week One: 6 tablets a day (M-F)
  • Week Two: 2 tables a day (M-F)
  • Week Three: Repeat Week One
  • Week Three: Repeat Week Two

Second Month: Repeat first month
Third Month: Stop Isoprinosine
Four Month: Repeat Month 1
Fifth Month: Repeat Month 1

Six Month: Stop Isopoprinosine

The Phoenix Rising website is compiled by a layman. It is not a substitute for a physician and is for informational uses only. It does not present complete information on this drug. Please discuss any treatments in these pages with your physician.


Dr. Cheney Discusses Th1, Th2, the Immune System and Chronic Fatigue Syndrome, 2000.

Isoprinosine Clinical Trial Shows Promise, 1999.

2009 IACFS/ME Conference: Treatment Section

Dr. Kenny De Meirleir Lecture On ME/CFS

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