For anyone interested. My apologies for the length: Page 241 Plumb
Handbook of Veterinary Drugs:
�DMSO is a clear, colorless to straw-yellow liquid. It is dipolar,
aprotic (acts as a Lewis base) and extremely hygroscopic. It has a
melting/freezing point of 18.5 C�It is miscible with water (heat is
produced), alcohol, acetone, chloroform, ether and many organic
solvents�
Storage/Stability/Compatibility � Must be stored in airtight
containers and away from light. As DMSO may react with some
plastics, it should be stored in glass or in the container provided
by the mfg. If DMSO is allowed to contact room air it will
self-dilute to a concentration of 66-67%. DMSO is apparently
compatible with many compounds, but because of the cancers for
accidental percutaneous absorption of potentially toxic compounds,
the admixing of DMSO with other compounds is not to be done
casually.
Pharmacology � The pharmacologic effects of DMSO are diverse. DMSO
traps free radical hydroxide and its metabolite, dimethyl sulfide
(DMS) traps free radical oxygen. It appears that these actions help
to explain some of the anti-inflammatory, cryopreservative,
antiischemic (improves blood flow) and radioprotective qualities of
DMSO.
DMSO will easily penetrate the skin. It also serves as a carrier
agent in promoting the percutaneous absorption of other compounds
(including drugs and toxins) that normally would not penetrate.
Drugs such as insulin, heparin, phenylbutazone, and sulfonamides
will be absorbed systemically when mixed with DMSO…
DMSO has weak antibacterial activity when used clinically and
possible clinical efficacy when used topically as an antifungal. The
mechanism for these antimicrobial effects has not been elucidated.
The anti-inflammatory/analgesic properties of DMSO have been
thoroughly investigated. DMSO appears to be more effective an
anti-inflammatory agent when used for acute inflammation versus
chronic inflammatory conditions. The analgesic effects of DMSO have
been compared to that produced by narcotic analgesics and is
efficacious for both acute and chronic musculoskeletal pain.
DMSO decreases platelet aggregation, but reports on its effects on
coagulability have been conflicting, as has its effect on the
myocardium (heart muscle). DMSO has diuretic activity independent of
the method of administration. It also provokes histamine release
from mast cells, which probably contributes to the local
vasodilatory effects seen after topical administration. DMSO also
apparently has some anticholinesterase acitivity and enhances
prostaglandin E but blocks the synthesis of E2, F2 alpha, H2 and Gs.
It inhibits the enzyme alcohol dehydrogenase, which not only is
responsible for the metabolism of alcohol but also the metabolism of
ethylene glycol (antifreeze) into toxic metabolites.
Uses/Indications: Purported uses for DMSO are rampant, but the only
FDA-approved veterinary indication for DMSO is: �…as a topical
application to reduce acute swelling due to trauma� (Package
insert). Other possible indications include: adjunctive treatment in
transient ischemic conditions (frost-bite), CNS trauma and cerebral
edema, skin ulcers/wounds/burns, adjunctive therapy in intestinal
surgeries, and analgesia for post-operative or intractable pain,
amyloidosis in dogs, reduction of mammary engorgement in the nursing
bitch, enhancement of antibiotic penetration in mastitis in cattle
and limitation of tissue damage following extravasation injuries
secondary to chemotherapeutic agents. DMSO�s effect on alcohol
dehydrogenase many make it useful in the treatment of ethylene
glycol poisoning, but this has not been sufficiently studied as of
yet. DMSO�s attributes as a potential carrier of therapeutic agents
across the skin and into the systemic circulation and its
synergistic effects with other agents are potentially exciting, but
require more study…
Pharmacokinetics � DMSO is well absorbed after topical
administration…it is extensively and rapidly distributed to
virtually every area of the body�DMSO is metabolized to dimethyl
sulfide (DMS) and is primarily excreted by the kidneys although
biliary and respiratory excretion also takes place.
Contraindications/Precautions � Wear rubber gloves when applying
topically and apply with clean or sterile cotton to minimize the
chances for contamination with potentially harmful substances. Apply
only to clean, dry areas to avoid carrying other chemicals�DMSO may
mask existing pathology with its anti-inflammatory and analgesic
activity. Because DMSO may degranulate mast cells, use with extreme
caution in animals with mastocytomas�used cautiously in animals
suffering from dehydration or shock as its diuretic and peripheral
vasodilatory effects may exacerbate these conditions.
Adverse Effects/Warnings � When used as labelled, DMSO appears to be
an extremely safe drug. Local effects (�burning�, erythema,
vesiculation, dry skin, local allergic reactions) and garlic or
oyster-like breath odor are the most likely adverse effects. They
are transient and quickly resolve when therapy is discontinued. …At
high doses…causes myopia and lenticular changes. These effects are
slowly reversible after the drug is discontinued. When administered
intravenously to horses it may cause hemolysis and hemoglobinuria.
…Reports of hepatotoxicity and renal toxicity have also been
reported for various species and dosages. These occur fairly rarely
and some clinicians actually believe DMSO has a protective effect on
ischemically insulted renal tissue. (It is currently being used in
human medicine as an important treatment for interstitial
cystitis�it�s scavenging of radical effects may be useful as a
preventative for certain types of cancer. My words)