DL-methionine kan inwendig gebruikt worden.
Martindale beschrijft:
L-Methionine is an essential amino acid and is therefore included in amino-acid solutions for parenteral nutrition […].
Methionine also enhances the synthesis fo glutathione and is used as an alternative to acetylcysteine in the treatment of paracetamol poisoning to prevent hepatotoxicity […]. The literature relating to the use of methionine in paracetamol poisoning is, in general, imprecise as to the form of methionine used. In the UK, the usual dose of DL-methionine is 2,5 g by mouth every 4 hours for 4 doses starting less than 10 to 12 hours after ingestion of the paracetamol. Children under 6 years old may be given 1 g very 4 hours for 4 doses. Methionine has also been given intravenously. Preparations containing both methionine and paracetamol have been formulated for use in situations where overdosage may occur. However, the issue of wether methionine should be routinely added to paracetamol prerarations is contentious for medical and ethical reasons.
Methionine has also been given orally to lower urinary pH and as an adjunct in the treatment of liver disoerders. It has also been used in the assessment of hyperhomocysteinaemia.
Acetylmethionine has also been used.
