Products
Methionine is commercially available in the form of tablets. Acimethine film-coated tablets, which require a prescription, were approved as a drug in 1988. Burgerstein L-Methionine is a dietary supplement with no indication.
Structure and properties
L-methionine (C7H13NO3S, Mr = 191.2 g/mol) is a natural, sulfur-containing, and essential amino acid used in the body for, among other things, the biosynthesis of proteins. Methionine exists as a white crystalline powder or as colorless crystals and is soluble in water.
Effects
Methionine (ATC V03AB26) causes urinary acidification, thereby inhibiting bacterial attachment to urothelial cells and bacterial growth. The effects are based on the formation of sulfate, which is excreted by the kidneys. In the process, protons are secreted into the urine and it becomes acidified. Methionine improves stone solubility, inhibits stone formation and improves the effect of some antibiotics. It is important in the body for the synthesis of S-adenosylmethionine, homocysteine, cysteine and taurine, among others.
Indications
- For urinary acidification in chronic urinary tract infections.
- For the prevention of phosphate stones.
- To optimize the effect of antibiotics with optimum action in acidic urine, such as ampicillin, carbenicillin, sulfonamides, nalidixic acid and nitrofurantoin.
- For parenteral nutrition (intravenous infusion solutions).
- As a food supplement.
Dosage
According to the professional information. As a rule, 500 to 1000 mg is taken three times a day before meals. Sufficient water should be drunk during treatment. Methionine is a precursor of homocysteine. High levels of this amino acid are considered a risk factor for cardiovascular disease. Therefore, during long-term therapy with methionine, care should be taken to ensure an adequate supply of B vitamins (B2, B6, B12) and folic acid. This is because these vitamins are involved in the breakdown of homocysteine.
Contraindications
- Hypersensitivity
- Metabolic acidosis, renal tubular acidosis.
- Severe hepatic insufficiency
- Hyperuricemia, hyperuricosuria
- Uric acid cystine diathesis
- Oxalosis
- Congenital metabolic disorders (eg, homocysteinuria).
- Severe renal insufficiency
- Infants, children under 12 years
Full precautions can be found in the drug label.
Interactions
The effects of drugs that are increasingly reabsorbed in the kidney as a result of urinary acidification may be increased. These include the antibiotics mentioned above. Another interaction has been described with levodopa.
Adverse effects
Possible adverse effects include acidification of the blood; gastrointestinal symptoms such as nausea, vomiting, and diarrhea; and irritability.