P. Kane, Ph.D. and J. Mercola, D.O.
What is DMSA and Why Don't We Recommend It?
DMSA is a FDA currently approved drug. It is a mixed disulfide in which each of the sulfur atoms is in disulfide linkage with a cysteine molecule forming water soluble chelates which increases the urinary excretion of lead.
There are a number of physicians who have started to use DMSA to remove the mercury from children with autism. The dose used for mercury detoxification is much lower than that for lead and some children seem to have received benefit from this approach.
A time released DMSA has been suggested for 7 days on, 7 days off or 3 days on, 4 days off for an extended period of time (up to 6 months).
However, some natural medicine clinicians have some serious concerns about the use of DMSA.
There have been cases of:
- seizures
- increased self-stimming
- and compromised central nervous system function in some children
DMSA and Mercury Redistribution To The Brain
It appears that DMSA and lipoic acid can create tissue redistribution of mercury as decreasing Hg levels in the kidney (the organ accumulating Hg most abundantly) increases Hg concentrations of Hg in blood, brain, lung, heart, muscle and liver (Gregus et al).
Natural medical physicians throughout the US have reported MS symptoms in adults and intractable seizures in pediatric patients with high dose and extended use of DMSA (2, 3-dimercaptosuccinic acid), Chemet or Succimer.
Other Problems With DMSA
Extended use of DMSA can cause mild to moderate neutropenia with increased SGOT, SGPT, Platelet count, Cholesterol, Alkaline Phosphatase and Blood Urea Nitrogen (BUN). Adverse reactions to DMSA include ataxia, convulsions, rash, nausea, diarrhea, anorexia, headache, dizziness, sensorimotor neuropathy, decreased urination, arrhythmia, infection. Zinc excretion doubles during the administration of DMSA. Patients must be kept hydrated as renal function can be compromised.
For the above described reasons in all good conscious we can not recommend the use of DMSA for the treatment of mercury toxic pediatric patients.
Approaching the fragile brain architecture of young children with autism, PDD and seizure disorders brings about tremendous responsibility in protecting the children from invasive interventions that risk alteration in brain function.
DMPS Recommended Chelating Agent
The physicians who support the use of DMSA claim that they do not use DMPS because it is an unapproved drug and the cost.
Both of these concerns are not valid as DMPS has undergone phase one and two FDA trials and has been approved for use distribution in bulk form by compounding pharmacists. Phase 3 trials were not completed due to lack of funding.
The medical literature favors DMPS over DMSA as the drug of choice. Challenge doses of DMSA to determine heavy metal load are often unremarkable as DMSA is a weak chelator. DMPS yields clinically useful spills of mercury and other heavy metals into the urine.
Dose for dose DMSA costs much less than DMPS. But since the DMPS is only used once per month, the total cost is actually significantly lower than DMSA which must be used 28 times per month.
Hair Analysis For Diagnosis and Treatment
First, a determination must be made if, in fact, there is a heavy metal burden and if so specifically which heavy metals are involved such as aluminum, mercury, lead or others.
This is the reason why hair analysis is a recommended initial screen. At this time we only advise two labs for this determination. Trace Elements in Austin, Texas and Analytical Research in Arizona.
Both of these labs do not wash the hair samples prior to analysis. This is a key factor to proper interpretation of the other nontoxic minerals.
Other labs would likely give proper heavy metal results, but the interpretation of the other minerals is key to an effective supplementation program. Chelation removes other minerals aside from mercury and these must be replaced properly if one wished to avoid complications.
Establishing Metabolic Stability Prior To Detoxification
One must be relatively healthy to sustain the process of detoxification. Once metabolic stability is established physicians often find that gentle biological interventions clear heavy metal burdens without the need for medication that holds the potential risk of negative side effects or merely redistribution of heavy metals.
Clearing heavy metals may be approached by first reestablishing the mineral base, supporting biliary function/ digestion, insuring the patient is properly hydrated (children with autism are frequently dehydrated), and most importantly supporting hepatic function and metabolism
Adults with heavy metal toxicity generally have significant suppression of omega 6 arachidonic acid and a significant elevation of very long chain fatty acids (Kane) as the cellular impact of heavy metals burdens block receptor sites such as G proteins and ultimately suppress the beta oxidation of lipids and cellular respiration.
Children with autism consistently present with an elevation of very long chain fatty acids.However, red cell lipid levels of arachidonic are variable, elevated in some patients while deeply suppressed in others.
Dietary Fat Intervention Must Be Considered
Administration of fish oils suppresses omega 6 and structural lipids and this will suppress the production of arachidonic acid. To balance fat metabolism it is crucial to stabilize omega 6 fatty acids and arachidonic acid before introducing omega 3 lipids.
Patient outcomes may be compromised if one uses fish oils prior to omega 6 fatty acids. The omega 6 fatty acid of choice would be evening primrose oil. Additionally, supporting the digestion of fats with bile salts and lipase is frequently required to maximize fat absorption and digestion.
Japan and Mercury Exposure Example
The impact of Hg upon human health was brought to light in the mid-50s with the Minamata disaster in Japan. As noted in the documentary 'Message to Minamata to the World' the impact of mercury is devastating, most prominently to the CNS. Interestingly, autistic behavior can observed in the documentary of Minamata children in original footage after the disaster.
In 1993 Kane found an interesting correlation in the literature between autism and mercury with the occurrence of autism presenting in adulthood occurring in Japan. The presentation of autism in these individuals was linked to ornithine transcarbamylase deficiency, the most common urea cycle defect. Damage to this enzyme can occur with exposure to mercury.
Low levels of ornithine transcarbamylase (OTC) leads to states of hyperammonemia, seizures and stroke. The enzyme OTC controls ammonia, critical issues in states of epilepsy and autism.
The often spacy, confused behavior 'brain fog' that is frequently observed in these disorders may be attributed states of hyperammonemia as ammonia reaches the brain.
Suggested treatment of mildly suppressed levels of OTC includes sodium benzoate and phenylacetate. However, Kane and other clinicians have observed positive clinical usefulness of Ca/Mg butyrate, digestive intervention targeted to biliary flow, appropriate buffers, and stabilization of electrolytes and the trace mineral base.
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