Also Known As: DMSO, Dimethyl sulfoxide
Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula (CH3)2SO. This colorless liquid is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is miscible in a wide range of organic solvents as well as water.
It penetrates the skin very readily and has the unusual property that many individuals perceive a garlic-like taste in the mouth after contact of DMSO with the skin. This perceived garlic odor may be due to nonolfactory activation of TRPA1 receptors in trigeminal ganglia. Unlike dimethyl and diallyl disulfide (also with odors resembling garlic), the mono- and tri- sulfides (typically disgusting), and similar structures, the pure chemical DMSO is odorless.
Use of DMSO in medicine dates from around 1963, when an Oregon Health & Science University Medical School team, headed by Stanley Jacob, discovered it could penetrate the skin and other membranes without damaging them and could carry other compounds into a biological system. In medicine, DMSO is predominantly used as a topical analgesic, a vehicle for topical application of pharmaceuticals, as an anti-inflammatory, and an antioxidant. Because DMSO increases the rate of absorption of some compounds through organic tissues, including skin, it is used in some transdermal drug delivery systems. Its effect may be enhanced with the addition of EDTA. It is frequently compounded with antifungal medications, enabling them to penetrate not just skin but also toe and fingernails.
DMSO has been examined for the treatment of numerous conditions and ailments, but the U.S. Food and Drug Administration (FDA) has approved its use only for the symptomatic relief of patients with interstitial cystitis. A 1978 study concluded that DMSO brought significant relief to the majority of the 213 patients with inflammatory genitourinary disorders that were studied. The authors recommended DMSO for genitourinary inflammatory conditions not caused by infection or tumor in which symptoms were severe or patients failed to respond to conventional therapy.
In medical research, DMSO is often used as a drug vehicle in in vivo and in vitro experiments. However, when a researcher is unaware of its pleiotropic effects, or when the control groups are not carefully planned, a bias can occur; an effect of DMSO can be falsely attributed to the drug. For example, even a very low dose of DMSO has a powerful protective effect against acetaminophen induced liver injury in mice.
In cryobiology DMSO has been used as a cryoprotectant and is still an important constituent of cryoprotectant vitrification mixtures used to preserve organs, tissues, and cell suspensions. Without it, up to 90% of frozen cells will become inactive. It is particularly important in the freezing and long-term storage of embryonic stem cells and hematopoietic stem cells, which are often frozen in a mixture of 10% DMSO, a freezing medium, and 30% fetal bovine serum. In the cryogenic freezing of heteroploid cell lines (MDCK, VERO, etc.) a mixture of 10% DMSO with 90% EMEM (70% EMEM + 30% fetal bovine serum + antibiotic mixture) is used. As part of an autologous bone marrow transplant the DMSO is re-infused along with the patient's own hematopoietic stem cells.
DMSO is metabolized to dimethyl sulfide and dimethyl sulfone. It is subject to renal and pulmonary excretion. A possible side effect of DMSO is therefore elevated blood dimethyl sulfide, which may cause a blood borne halitosis symptom.
DMSO is marketed as an alternative medicine via books with titles such as DMSO: Nature's healer. Its popularity as an alternative cure is stated to stem from a 60 Minutes documentary featuring an early proponent. It is listed by the U.S. FDA as a fake cancer cure and the FDA has had a "running battle" with distributors. This has included Mildred Miller who promoted DMSO for a variety of disorders including arthritis, mental illness, emphysema, and cancer and wrote a book touting DMSO entitled A Little Dab Will Do Ya! (Quality Advertising, 1981). The use of DMSO as a alternative treatment for cancer is of particular concern, as it has been show to interfere with a variety of chemotherapy drugs, including cisplatin, carboplatin and oxaliplatin It is still listed as an ineffective alternative cancer cure by the American Cancer Society; for most conditions there is insufficient evidence to state any effect and most sources agree that its history of side effects when tested indicates caution when using it as a dietary supplement, for which it is heavily marketed with the usual disclaimer.