Dimethyl sulfoxide (DMSO) is a chemical compound that is a subject of ongoing debate and controversy. This article explores the scientific basis and regulatory landscape surrounding DMSO.
Understanding DMSO
DMSO is a colorless liquid, first isolated in 1867 by Russian chemist Alexander Zaytsev. It is a byproduct of the kraft process, which makes paper from wood pulp. DMSO is a highly polar aprotic solvent, meaning it lacks acidic or basic properties and can dissolve both organic and inorganic compounds.
A notable property of DMSO is its ability to penetrate human skin with minimal tissue effects, enabling it to transport other substances into the body. This characteristic led to investigations into its potential as a vehicle for drug delivery. The compound gained attention in medical and alternative health circles beginning in the 1960s.
Approved and Unapproved Applications
The controversy surrounding DMSO largely stems from the difference between its limited, approved medical applications and its many unapproved uses. In the United States, the Food and Drug Administration (FDA) approved a 50% DMSO solution for intravesical administration, under the brand name Rimso-50, for the symptomatic relief of interstitial cystitis (bladder pain syndrome) in 1978. This remains its sole FDA-approved human indication. It is administered directly into the bladder via a catheter in a hospital or clinic setting and is believed to reduce inflammation, relax bladder muscles, and alleviate pain.
Beyond this specific approved use, DMSO is widely promoted for numerous unapproved applications. These include purported treatments for pain relief, inflammation, various chronic diseases, and even cancer. People use it for conditions such as osteoarthritis, rheumatoid arthritis, headaches, and to aid wound and burn healing. The promotion of these broader applications often relies on anecdotal evidence rather than robust scientific proof, contributing to the compound’s contentious status.
Safety Concerns and Reported Risks
Using DMSO, especially outside of approved medical supervision or for unapproved purposes, carries several known side effects and potential risks. A common side effect is a garlic-like odor on the breath and skin, which can last for several hours to up to three days after use. Other frequent reactions include skin irritation, redness, and itching, particularly with topical application of higher concentrations.
More serious concerns include the risk of allergic reactions and drug interactions. DMSO can increase levels of acetylcholine in the body, potentially heightening side effects when combined with medications that also affect acetylcholine. Using DMSO with sulindac, a pain medication, might also reduce sulindac’s effectiveness and increase the risk for nerve pain. A significant risk arises from the purity of DMSO, as industrial-grade products, often sold through unregulated sources, may contain contaminants like pesticides. Due to DMSO’s ability to easily penetrate the skin and carry other substances, these impurities can be absorbed into the body, potentially leading to serious health issues.
The Scientific and Regulatory Divide
The broader scientific and medical communities maintain a cautious stance on the widespread use of DMSO, primarily due to a lack of large-scale, rigorous clinical trials to substantiate most of its purported benefits. While initial interest in DMSO was high in the 1960s, a temporary ban on clinical trials by the FDA in 1965, due to observed eye lens changes in laboratory animals, significantly curtailed research. Although the ban was lifted in 1980, extensive research has not been rekindled.
Regulatory bodies, like the FDA, require robust scientific evidence, typically from randomized, placebo-controlled clinical trials, to approve a drug for specific uses. For many of the unapproved applications of DMSO, such comprehensive studies are either limited or nonexistent. This reliance on anecdotal accounts rather than evidence-based medicine contributes significantly to DMSO’s controversial standing within the established medical framework.