Other common name(s): Isoprinosine®, Imunovir®, methisoprinol, inosiplex, inosinpanobex
Scientific/medical name(s): none
Inosine pranobex is a drug that may mimic the actions of immune-stimulating hormones made in the thymus gland. It is used primarily in European countries, mainly as a treatment for viral infections. It is not used for cancer treatment by conventional oncologists in Europe or anywhere else, but is occasionally recommended on alternative medicine Web sites as an anticancer treatment or for enhancing immunity of people living with cancer.
Available scientific evidence does not support claims that inosine pranobex is effective in treating cancer. The drug is not approved by the U.S. Food and Drug Administration (FDA) and cannot be sold legally in pharmacies in the United States.
How is it promoted for use?
Proponents claim inosine pranobex strengthens the immune system and fights viral infections. They also say it may lower the risk of infection in people being treated for cancer, who often have weakened immune systems. Some assert that it may boost the effects of interferon, which is a drug sometimes used against viral infections and certain types of cancer. Inosine pranobex may also increase the activity of helper T-cells and natural killer cells (types of white blood cells), which may help stop tumors from growing. Some practitioners recommend it as an alternative to conventional cancer therapy. Others suggest that inosine pranobex be used along with mainstream cancer treatment
At one time inosine pranobex was promoted as a way for athletes to improve their endurance and performance, although studies have not borne this out. More recently, it has been promoted for possible use against chronic fatigue syndrome. It is currently used (mostly in European countries) to treat people with AIDS and other viral diseases, including herpes, shingles, warts, influenza, the common cold, and viral infections of the liver (hepatitis) and brain (encephalitis).
What does it involve?
Inosine pranobex is taken as a capsule or tablet. There is no standard dosage, although some studies have used between 1 and 4 grams per day. Some practitioners recommend a maximum of 3 grams per day for autoimmune diseases, with the daily dose divided up and spread evenly throughout the day (for instance, 1 gram every 8 hours for a total of 3 grams per day.) Some further suggest that the dose be "pulsed," that is, taken for a week or 2 then stopped for up to a month before restarting.
What is the history behind it?
Inosine pranobex was patented in the late 1960s, and has been studied against a number of viral conditions as far back as the early 1970s. In 1981, the FDA refused to allow the drug to be marketed in the United States, citing a lack of evidence that it was effective. Today it is sold in Europe and elsewhere as a treatment for a number of viral diseases including herpes, influenza, and viral hepatitis.
What is the evidence?
A number of animal and laboratory studies—done mostly in Europe—have found that inosine pranobex increases the activity of helper T-cells and natural killer cells. Although a substantial increase in activity of these immune system cells could slow the growth of tumors, there is no reliable clinical evidence that inosine pranobex is of any clinical value in the treatment of people with cancer.
Thus far, very few studies have looked at the effectiveness of inosine pranobex against cancer in people. A French study found no difference in survival or recurrence rates between 60 lung cancer patients treated with surgery alone and another 60 treated with surgery and inosine pranobex. In another, much smaller study, researchers concluded that inosine pranobex combined with the chemotherapy drug 5-fluorouracil was not effective in the treatment of metastatic colorectal cancer. The most recent clinical trial, published in 2003, reported no benefit in patients with melanoma (a type of skin cancer). A 1978 article reported no benefit of inosine pranobex in treating pediatric cancer patients with herpes virus infections. There appears to be little current research on the use of inosine pranobex against cancer.
Based on a large study conducted in Sweden and Denmark, researchers reported in 1990 that inosine pranobex delays the onset of AIDS in people with HIV infection. However, the FDA pointed out several important flaws in the study and noted that other large studies have not found inosine pranobex to be helpful. The FDA concluded that more study was needed before its value for HIV-infected patients could be sufficiently evaluated. There has been substantial progress in treatment of HIV infection and AIDS since 1990, and researchers in this field have since turned their attention to more promising drugs.
Several small studies have suggested that inosine pranobex may be effective, when combined with interferon, to treat subacute sclerosing panencephalitis, a fairly rare brain infection caused by the measles virus. Some studies suggest inosine pranobex may be useful as a treatment for genital warts. More research is needed to confirm these findings.
Are there any possible problems or complications?
The safety of inosine pranobex has not been studied extensively, although it seems to be fairly well tolerated. Some studies have reported possible side effects including dizziness, stomach upset, and heartburn. Inosine pranobex increases blood levels of uric acid, which can increase the risk of gout or kidney stones. Interactions with other drugs are unknown. Talk with your doctor and pharmacist about all the medicines and supplements you are taking before adding inosine pranobex.
Information on pregnancy and breast-feeding is not available. Relying on this type of treatment and avoiding or delaying conventional medical care for cancer, may have serious health consequences.
More information from your American Cancer Society
The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-ACS-2345).
The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management
Colozza M, Tonato M, Belsanti V, et al. 5-Fluorouracil and isoprinosine in the treatment of advanced colorectal cancer. A limited phase I, II evaluation. Cancer.1988;15:1049-1052.
Feldman S, Hayes FA, Chaudhary S, Ossi M. Inosiplex for localized herpes zoster in childhood cancer patients: preliminary controlled study. Antimicrob Agents Chemother. 1978;14:495-497.
Gascon GG. International Consortium on Subacute Sclerosing Panencephalitis. Randomized treatment study of inosiplex versus combined inosiplex and intraventricular interferon-alpha in subacute sclerosing panencephalitis (SSPE): international multicenter study. Journal of Child Neurology.2003;18:819-827. Erratum in: J Child Neuro. 2004;19:342.
Georgala S, Katoulis AC, Befon A, Georgala C, Rigopoulos D. Oral inosiplex in the treatment of cervical condylomata acuminata: a randomised placebo-controlled trial. BJOG: An International Journal of Obstetrics & Gynaecology.2006;113;1088-1091.
Imunovir Data Sheet. Medsafe Accessed at: http://www.medsafe.govt.nz/Profs/Datasheet/i/Imunovirtab.htm on September 1, 2008.
Khayat D, Rixe O, Martin G, Soubrane C, Banzet M, Bazex JA, Lauret P, Verola O, Auclerc G, Harper P, Banzet P, French Group of Research on Malignant Melanoma. Surgical margins in cutaneous melanoma (2 cm versus 5 cm for lesions measuring less than 2.1-mm thick). Cancer. 2003;97:1941-1946.
Kweder SL, Schnur RA, Cooper EC. Inosine pranobex -- is a single positive trial enough? N Engl J Med.1990;322:1807-1809.
Pedersen C, Sandstrom E, Petersen CS, et al. The efficacy of inosine pranobex in preventing the acquired immunodeficiency syndrome in patients with human immunodeficiency virus infection. The Scandinavian Isoprinosine Study Group. N Engl J Med.1990;322:1757-1763.
Erratum in: N Engl J Med. 1990;323:1360.
Roeslin N, Dumont P, Morand G, Wihlm JM, Witz JP. Immunotherapy as an adjuvant to surgery in carcinoma of bronchus. Results in three randomised trials. Eur J Cardiothorac Surg.1989;3:430-435.
Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.
Last Revised: 11/01/2008