Milk-alkali syndrome (MAS), also referred to as calcium-alkali syndrome, is the third most common cause of hypercalcemia. Milk-alkali syndrome is characterized by elevated blood calcium levels, metabolic alkalosis, and acute kidney injury.Milk-alkali syndrome can be caused by the excessive intake of calcium and absorbable alkali. Sources of calcium and alkali include dietary supplements taken for the prevention of osteoporosis or hyperparathyroidism and antacids taken for peptic ulcer disease. Common acute symptoms of milk-alkali syndrome include nausea and vomiting, dry mouth, confusion, lethargy, and distaste for milk. If left untreated, milk-alkali syndrome may lead to kidney failure or even death. Signs and symptoms
The signs and symptoms of milk-alkali syndrome can develop after only a few days and up to several months following the initial ingestion of absorbable calcium and alkali. However, the severity of signs and symptoms of milk-alkali syndrome is largely dependent upon the duration and quantity of calcium and alkali ingested.Acute milk-alkali syndrome is characterized by several biochemical alterations, mainly alkalosis, hypochloremia, hypokalemia, and hypercalcemia. In the acute phase of milk-alkali syndrome (Cope syndrome), the first symptoms of toxicity are nausea, vomiting, anorexia, headache, dizziness, vertigo, apathy, weakness, confusion, irritability, dry mouth, and repulsion to milk. In individuals with chronic milk-alkali syndrome (Burnett syndrome), symptoms may include muscle aches, psychosis, tremor, polyuria (producing large volumes of dilute urine), polydipsia (intense thirst), pruritus (itchy sensation on skin), band keratopathy and abnormal calcifications.
Toxicity is associated to both dose and duration of treatment. Hence the use of (S,S)-enantiomer greatly improved the risk/benefit balance. Medical uses
Ethambutol is used along with other medications to treat a number of infections including: tuberculosis, Mycobacterium avium complex, and Mycobacterium kansasii. Adverse effects
Optic neuritis (hence contraindicated in children below six years of age)
Red-green color blindness People taking ethambutol should be monitored for changes in visual acuity and color discrimination. Arthralgia
Hyperuricaemia
Vertical nystagmus
Milk skin reaction

Mechanism of action
Ethambutol is bacteriostatic against actively growing TB bacilli. It works by obstructing the formation of cell wall. Mycolic acids attach to the 5-hydroxyl groups of D-arabinose residues of arabinogalactan and form mycolyl-arabinogalactan-peptidoglycan complex in the cell wall. It disrupts arabinogalactan synthesis by inhibiting the enzyme arabinosyl transferase. Disruption of the arabinogalactan synthesis inhibits the formation of this complex and leads to increased permeability of the cell wall. Pharmacokinetics
It is well absorbed from the gastrointestinal tract and well distributed in body tissues and fluids. 50% is excreted unchanged in urine. See also
chiral drugs
chirality
enantiopure drug
stereochemistry

References
External links
"Ethambutol". Medicine Plus. "Ethambutol". Drug Information Portal. U.S. National Library of Medicine.