Dimethyl Sulfoxide (DMSO)
Dimethyl sulfoxide, or DMSO, is a highly penetrant organic solvent with several pharmacologic effects. Veterinary topical products are used to reduce acute traumatic swelling, particularly in horses and, with appropriate products, dogs. Systemic or additional anti-inflammatory applications are largely empirical and have a much weaker clinical evidence base.
Group
Solvent with anti-inflammatory properties
Mechanism of Action
DMSO penetrates biological membranes and can scavenge reactive oxygen species, including hydroxyl radicals, reducing some oxidative reactions in experimental systems. Proposed additional effects include modification of membrane properties and local inflammatory responses. These actions may contribute to reduction of swelling, but the precise relationship between individual molecular effects and clinical benefit is incompletely defined.
Dose Rates
Dog
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Inflammation adjunct | 1 g/kg | IV | Do not use in: IV concentration above 10%; Infuse slowly at a concentration no greater than 10%. Do not exceed 1 g/kg. |
Cat
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Inflammation adjunct | 1 g/kg | IV | Do not use in: IV concentration above 10%; Infuse slowly at a concentration no greater than 10%. Do not exceed 1 g/kg. |
Horse
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Inflammation adjunct | 1 g/kg | IV | Every 12 h | Do not use in: IV concentration above 10%; Infuse slowly at a concentration no greater than 10%. Do not exceed 1 g/kg. |
| Surgical colic adjunct | 25 mg/kg | IV | Every 12 h | Up to 2 days; Begin intraoperatively; the described postoperative course is 24–48 hours. Use a suitably diluted IV formulation. |
| Acute rhabdomyolysis adjunct | 1 g/kg | IV, PO | Only after hydration is restored; described as a 10% solution in balanced crystalloid. | |
| Laminitis adjunct | 0.1–1 g/kg | IV | Every 8–12 h | Do not exceed 10% IV concentration. |
Cattle
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Inflammation adjunct | 1 g/kg | IV | Every 12 h | Do not use in: IV concentration above 10%; Infuse slowly at a concentration no greater than 10%. Do not exceed 1 g/kg. |
Indications
- Topical reduction of acute swelling associated with trauma in horses and dogs, using a product indicated for the species.
- Empirical adjunctive treatment of selected equine inflammatory conditions, including synovitis or soft-tissue inflammation; evidence for disease-specific clinical benefit is limited.
Contraindications
- Do not administer concentrated DMSO IV or use IV concentrations above 10%.
- Avoid IV amounts above 1 g/kg.
Interactions
- Enhances penetration of contaminants or other chemicals through skin.
Adverse effects
- Skin and mucosal irritation
- Hemolysis, colic, diarrhea, tremors or collapse with concentrated/high-dose IV use
- Odor; lens changes after prolonged laboratory exposure
Toxicity
Concentrated IV administration can cause serious hemolysis and systemic reactions.
Monitoring and Administration
Use clean skin for topical administration. Dilute IV solutions to no more than 10% and administer slowly.
Monitor CBC and clinical response. Evidence does not establish efficacy for equine intestinal reperfusion injury, laminitis or neurologic disease.
For persistent cyclophosphamide-associated hemorrhagic cystitis, the source describes intravesical instillation of 10 mL medical-grade 50% DMSO mixed with 10 mL water, retained for 20 minutes then removed. Intravesical administration is not a supported calculator route.