Why is Dimethyl Sulfoxide (DMSO) not used more widely?

Limited Medical Use of DMSO: Understanding the Restrictions

DMSO (dimethyl sulfoxide) is not widely used in medical practice primarily due to its significant adverse effects profile, limited FDA approvals, and the availability of safer alternatives, despite its potential benefits in specific applications.

Current Approved Medical Uses

DMSO has limited approved medical applications:

• FDA-approved for diclofenac sodium topical solution for osteoarthritis 1
• Approved in Europe for idoxuridine topical solution for herpes zoster treatment 1
• FDA-approved for the palliative treatment of interstitial cystitis 2
• Used in cryopreservation of stem cells 3

Safety Concerns Limiting Widespread Use

Adverse Reactions

• Gastrointestinal and skin reactions are the most commonly reported adverse effects 3
• Dose-dependent relationship with adverse effects - higher concentrations cause more side effects 4
• Local reactions include:
  • Skin rash and pruritus after dermal application
  • Erythema that may affect evaluation of tissue damage
  • Local irritation, especially at higher concentrations 4, 2

Administration Challenges

• Mechanical difficulties with intravenous administration due to DMSO's solvent properties dissolving standard IV infusion systems 5
• Complex to use in clinical settings, particularly for intracranial hypertension treatment 5
• Potential for fluid overload and severe electrolyte disturbances with IV administration 5

Drug Interaction Concerns

• Safety of DMSO in combination with other drugs is not fully established
• Reported neurotoxic interactions with sulindac 4, 2

Concentration and Safety Guidelines

• For any route of administration, DMSO concentration should not exceed 10% to minimize adverse reactions 4
• For experimental agents in animal studies, DMSO should not exceed 5 ml/kg or 10% of injected volume 4
• Starting with lower concentrations (around 50%) is recommended to minimize skin irritation for topical applications 4

Potential Applications with Limited Evidence

Despite limited approvals, DMSO shows potential in several areas:

• Penetration enhancer for topical medications 4, 1
• Treatment option for extravasations during chemotherapy infusions (evidence level III, B) 4
• Pain management, particularly for neuropathic pain 4
• Treatment for cutaneous manifestations of scleroderma (equivocal evidence) 2
• Potential benefit in amyloidosis treatment through mobilizing amyloid deposits 2
• Enhancer in photodynamic therapy for basal cell carcinoma 4

Barriers to Wider Adoption

1. Lack of quality clinical trials: Most studies lack proper experimental design for objective statistical evaluation of efficacy 2
2. Regulatory limitations: Restricted by FDA to specific applications 2
3. Commercial factors: As an inexpensive, non-patentable substance, pharmaceutical companies have limited incentive for development 6
4. Safety profile concerns: Despite most adverse effects being transient, the risk-benefit profile favors newer alternatives in many cases 3

Monitoring Recommendations

When DMSO is used clinically:

• Document baseline symptoms before treatment
• Assess for adverse effects regularly
• If using for pain management, reassess using validated pain scales at 2-4 weeks
• Consider alternative treatments if no improvement after 4-6 weeks 4

DMSO remains underexplored despite being inexpensive and having potential therapeutic applications. The limitations in its wider adoption stem primarily from its adverse effect profile, limited regulatory approvals, and the pharmaceutical industry's lack of interest in developing a non-patentable substance.