Post on 12-Feb-2018
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Mike Carnes, D.O., F.A.A.O.
University of Pikeville
Kentucky College of Osteopathic Medicine
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N-methyl-D-aspartate (NMDA) receptors Ca2+channel that is blocked physiologically by Mg2+
Methadone is unique amongst the narcotics
Zinc also can block these receptors
Neuropathic pain Neuronal damage
Acute excitotoxic activity and oxidative stress with rapidCa2+influx
Delayed signaling leading to cell apoptosis is a problemwhen the receptors are blocked pharmacologically
Searching for a pathologically activated NMDA receptorantagonist
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Mitochondrial ATP production
Cofactor in thiamine dependent reactions Cofactor in Na+K+ATPase activity
K+secretion block (deficiency of Mg2+ low K+)
Can inhibit acetylcholine release (myasthenia gravis)
Deficiency may lead to hypocalcemia 20to effect on PTHsecretion
Aerobic metabolism, anaerobic metabolism, glycolysis,oxidative phosphorylation
Cofactor in some 300 enzymatic reactions
Low Mg2+& vitamin D (and some other micronutrients)can contribute to accelerated aging and adverseoutcomes
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Adult
25 grams Bone 50%
25% of the total body Mg2+insoluble mineral phase
99% of extraskeletal Mg2+is intracellular
Less than 1% of total body magnesium is in ECF Serum concentrations are closely regulated by the body
30% protein bound
15% loosely complexed to phosphate and other anions
Serum level below 1.8 mg/dL is indicative of total bodymagnesium deficit
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Nuts, unpolished grains, green leafy vegetables, halibut
Meats, lentils, starches, milk Absorbed in distal jejunum and ilium (30 40%)
1, 25-(OH)2D can stimulate this to reach 70% in times ofmagnesium depletion
Low protein diets (less than 30 grams/day) decreasesmagnesium absorption
RDA
Women 360 mg/d (14-18) tapers to 320 mg/d Men 420 mg/d gradually increasing with age
60 % of US population does not get their RDA
Excreted by nephron in the loop of Henle
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Extremely rare in the absence of renal dysfunction % absorbed inversely related to amount ingested
Renal function may worsen with supplementation
Tetanus therapeutic dose may also effect diaphragm
4.8 mg/dL - hypotension, neuromuscular blockade
9 mg/dL - loss of DTRs, respiratory suppression, nausea,
lethargy 20 mg/dL asystole
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Neuropathic pain
Migraines/headache, Bruxism, Nocturnal muscle cramp
Chronic Fatigue Syndrome / Fibromyalgia
Sickle crisis / anemia (pain, RBC dehydration, vascular
adhesion) Dysmenorrhea
Post-operative pain
Ischemic stroke
Asthma Acute nebulized or IV
Chronic oral
Cardiac arrhythmias (particularly QT prolongation)
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Oral increase by one tab every 3 4 days to bowel
tolerance, then decrease by one tab Topical MgCl 20% cream
Epsom Salt soak (MgCl)
Parenteral
for pain or spasm with intact renal function 4 gram dose intraoperatively
1 1.5 grams per hour
Scale 2.4 2.5 mg/dL = 1 gram mag sulfate in 50 cc NS
2.2 2.3 mg/dL = 2 grams mag sulfate in 100 cc NS
2.0 2.1 mg/dL = 3 grams mag sulfate in 150 cc NS
1.8 1.9 mg/dL = 4 grams mag sulfate in 250 cc NS
1.6 1.7 mg/dL = 6 grams mag sulfate in 250 cc NS
1.5 or below = 8 grams mag sulfate in 500 cc NS
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Harrison's Principles of Internal Medicine, 18th Edition.McGraw-Hill Professional Publishing, 07/2011.
Present Knowledge in Nutrition, 10th Edition., John Wiley& Sons, Inc., 2012