Science
By JULIE A. DUTTON

Is there balm in DMSO?

DIMETHYL SULFOXIDE — DMSO — a by-product of paper manufacturing, was touted by some in the early 1960's as a remedy for burns, sprains, bruises, and arthritis. Recently, interest in DMSO has been rekindled in the wake of a growing demand for the substance and controversy over its usefulness. The issue centers around the Food and Drug Administration's (FDA) hesitation to approve DMSO and the subsequent pressure from a public increasingly convinced the FDA is withholding a "wonder drug." The FDA does not regulate intrastate use, and two states have already legalized DMSO: Oregon, where much of the DMSO work has been conducted, and Florida, which has a large population of senior citizens. So far, Illinois has not addressed the DMSO problem.

DMSO has been used industrially since the 1940's as an antifreeze and a chemical solvent; it is also a veterinary treatment useful for its liniment-like properties. But even after almost twenty years of experimental human use, there are many unanswered questions about DMSO's therapeutic value. Unconvinced of DMSO's medicinal claims and suspicious of its potential side effects (including nausea, headache, and skin rash), the FDA has closely supervised investigations of DMSO. A 1972 report by the National Academy of Sciences confirms FDA's cautious approach. The study concluded that the efficacy of DMSO has not yet been established; DMSO should retain its investigatory status, and better controlled research is needed.

DMSO has a lengthy regulatory history. By 1965, the drug had been administered experimentally to over 100,000 people, but its therapeutic claims were still not substantiated. In November of 1965, the FDA terminated the clinical use of DMSO because animal studies linked it to eye damage. The next year, the ban was eased to permit DMSO investigations in connection with specific ailments. The restrictions were further relaxed in 1968 to permit short-term use (14 days) in the treatment of sprains, bursitis and tendonitis. As of June 1980, the FDA revoked all regulations that established specific requirements for the clinical testing and investigational use of DMSO. The ban was lifted because the FDA felt DMSO testing did not require special regulations but could be controlled under existing regulations for investigating new drugs.

In order for a sponsor (such as a clinical investigator or drug manufacturer) to investigate the safety and effectiveness of a new drug, an Investigational New Drug application must be filed with the FDA. Should the sponsor's studies conclude a drug is safe and effective, that information, as well as information on manufacturing procedures and controls, is submitted to the FDA as a New Drug Application (NDA). The FDA reviews the information, and if it approves the NDA, the drug may be marketed.

At present, the only NDA granted for DMSO (and therefore, the only FDA-approved use of the drug) is for a 50 percent concentration of DMSO to treat interstitial cystitis, a bladder ailment. (Seventy percent DMSO is the strength believed necessary for arthritis treatment; 90 percent is used for veterinary applications, and 100 percent for industrial use.)

Unconvinced of DMSO's medicinal claims and suspicious of its potential side effects, the Food and Drug Administration has closely supervised investigations of DMSO

Most DMSO tests have been rejected by the FDA as improperly conducted or inconclusive. These judgments have brought about pressure from those who feel the FDA is withholding a "wonder drug" for pain, spasms and tenderness. An FDA spokesman cites DMSO as "an efficacy issue": whether it is effective in treating the variety of ailments it purports to has yet to be established.

Part of the difficulty of assessing DMSO is due to its unique characteristics. About three percent of the drug is given off through the lungs as dimethyl sulphide, which imparts a garlic odor to the user's breath. This prevents "double blind" studies in which patients receive either the test drug or a placebo, but neither they nor the doctors know which until the study is over.

Test results can sometimes be ambiguous as well. The same company that was awarded FDA approval of DMSO for use in interstitial cystitis also sought to market it for scleroderma, a crippling disorder of the hands and other tissues. In its study, the company treated only one hand of each patient with DMSO; the other hand was untreated to serve as a control. Most patients showed improvement, often quite a bit of it. But improvement was seen in both hands. This improvement, the company claimed, was due to DMSO; the body had absorbed the DMSO to such an extent that the untreated hand had also improved. The FDA felt otherwise. The advisory committee of the FDA agreed that DMSO may be effective, but said there was too great a possibility that the healing effects could instead be attributed to the increased medical attention or to spontaneous improvement. The NDA for scleroderma was rejected. However, the FDA was sufficiently encouraged by the possibility of treating scleroderma with DMSO that it has encouraged the National Institutes of Health to provide funding for further investigations.

The lack of full FDA approval of DMSO has not prevented its use. Besides being legal in Oregon and Florida, DMSO is available in Mexican "clinics." Industrial or veterinary grade DMSO is sometimes used illegally as medicine. This is particularly risky because such DMSO is highly concentrated and can contain impurities. DMSO so readily penetrates the skin that it acts as a "vehicle," transporting other substances — including impurities — into the bloodstream.

The National Arthritis Foundation concurs with the FDA that DMSO has had inadequate scientific testing. According to Peter Mathon of the foundation, DMSO sales are "preying on the false hopes of arthritis victims," of which there are 31 million in the U.S. The issue, says Mathon, has turned into the policy question: "What is the correlation between public demand and scientific priorities?"

The FDA itself is certainly aware of the "bad guy" image the DMSO issue has given it. In a statement before the Select Committee on Aging, U.S. House of Representatives, the FDA emphasized that the agency does not want "to deny, or be unsympathetic to, the potential of DMSO ... the FDA is willing, indeed anxious, to approve DMSO. ..." But equally clear was the agency's firmness on the conditions it has set for NDA approval: controlled DMSO tests conducted with unquestionable standards.

Support for this column, which reports policy developments concerning science and technology, is provided in part by a National Science Foundation grant to the Illinois Legislative Council Science-Unit, where Julie A. Dutton is a research associate.

24/November 1980/Illinois Issues