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Don't treat yourself with methionine. It is POSSIBLY UNSAFE to self-medicate with methionine if you use larger amounts than those typically found in food. Too much methionine can cause brain damage and death. Methionine can increase blood levels of homocysteine, a chemical that might cause heart disease. Methionine might also promote the growth of some tumors.
Special Precautions & Warnings:Children: Methionine is POSSIBLY SAFE for children when given by mouth or injected intravenously (by IV) to treat acetaminophen poisoning, but only under the supervision of a healthcare professional. Methionine is POSSIBLY UNSAFE when injected intravenously into infants that are receiving parenteral nutrition.
Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking methionine if you are pregnant or breast-feeding. Stay on the safe side and avoid use.
Acidosis: Methionine can cause changes in acidity of the blood and should not be used in people with a condition called acidosis.
"Hardening of the arteries" (atherosclerosis): There is some concern that methionine might make atherosclerosis worse. Methionine can increase blood levels of a chemical called homocysteine, especially in people who don't have enough folate, vitamin B12, or vitamin B6 in their bodies, or in people whose bodies have trouble processing homocysteine. Too much homocysteine is linked to an increased risk for diseases of the heart and blood vessels.
Liver disease, including cirrhosis: Methionine might make liver disease worse.
Methylenetetrahydrofolate reductase (MTHFR) deficiency: This is an inherited disorder. It changes the way the body processes homocysteine. People who have this disorder should not take methionine supplements because methionine might cause homocysteine to build up in these people. Too much homocysteine might increase the chance of developing diseases of the heart or blood vessels.
Schizophrenia: Large doses of methionine (e.g., 20 g/day for 5 days) might cause confusion, disorientation, delirium, agitation, listlessness, and other similar symptoms in people with schizophrenia.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.