Dimethyl sulfoxide (DMSO) toxicology, pharmacology, and clinical experience

1. 1. In subacute and chronic animal experiments, dimethyl sulfoxide administered topically, subcutaneously, intraperitoneally, orally, into the eye, and to the mucous membrane is generally well tolerated and rates as an agent of low toxicity. 2. 2. Subacute and chronic administration of DMSO in relatively high concentrations to dogs, rabbits, and swine by either the oral or the topical routes results in alterations to the lens. These alterations do not occur when the average dose given to human subjects is applied. The rhesus monkey is much more resistant to this phenomenon than the dog, rabbit, or pig. 3. 3. Human subjects have now been examined ophthalmologically after as long as two and a half years of DMSO therapy without ocular toxicity. DMSO is clinically well tolerated, with few troublesome side effects. 4. 4. Fate and metabolism of DMSO have been studied in man by radioactive technics. After cutaneous application half of the applied dose is eliminated within fourteen days. After intravenous application half of the applied dose is eliminated within eight days. Most of the dose is excreted as unchanged dimethyl sulfoxide in the urine. Dimethyl sulfone also appears in the urine. Dimethyl sulfide has been identified as the breath odor which follows DMSO treatment. 5. 5. Dimethyl sulfoxide has a wide range of primary pharmacologic actions including membrane penetration, anti-inflammation, local analgesia, bacteriostasis, diuresis, cholinesterase inhibition, enhancement of the action of a concomitantly administered drug, solvent for collagen, nonspecific enhancement of immunity, and vasodilation. Clinical usefulness in surgery and the surgical subspecialities has been shown in the treatment of acute trauma, postoperative incisional pain, certain urologie disorders such as Peyronie's disease, early Dupuytren's contracture, keloids, and subcutaneous fibrosis associated with cobalt irradiation. Dimethyl sulfoxide will effectively carry local anesthetics into the deeper layers of the skin and into the ear drum, permitting incision without pain.