methionine

Action and Spectrum

Actions and Spectrum: 

It plays crucial roles in protein synthesis, methylation reactions, and the production of various molecules involved in cellular processes. While methionine itself does not have a direct antibiotic or therapeutic action like some drugs, its biological functions are essential for overall health. 

• Protein Synthesis: methionine is the initiating amino acid in protein synthesis. The start codon (AUG) codes for methionine, which is often removed after translation to form the mature protein. 
• Methylation Reactions: methionine is a precursor for S-adenosylmethionine (SAM), which is a crucial methyl donor in various methylation reactions. Methylation is a common post-translational modification of proteins and is involved in the regulation of gene expression, protein function, and cellular processes. 
• Antioxidant Properties: methionine contains a sulfur atom, and its derivatives have antioxidant properties. These properties are important for protecting cells from oxidative stress and damage caused by free radicals. 
• Detoxification: methionine is involved in the synthesis of glutathione, an essential antioxidant and detoxifying agent in the body. Glutathione helps neutralize harmful substances and plays a role in detoxifying drugs and pollutants. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Nausea and vomiting 

Drowsiness 

Black Box Warning

Black box warning: 

None 

Contraindication / Caution

Contraindications/caution: 

Contraindications: 

• Allergies or Sensitivities: Individuals with allergies or sensitivities to methionine or any of its derivatives should avoid supplementation. 
• Kidney Disorders: Individuals with kidney disorders may need to be cautious with methionine supplementation. Methionine metabolism involves the kidneys, and excessive methionine intake may be problematic for individuals with impaired kidney function. 
• Liver Disorders: methionine metabolism is closely linked to liver function. Individuals with liver disorders should exercise caution with methionine supplementation, as it may affect liver function. 
• Homocystinuria: Homocystinuria is a rare genetic disorder characterized by the inability to metabolize methionine properly. Individuals with this condition should avoid excess methionine intake. 
• Cardiovascular Disease: High levels of methionine in the diet have been associated with an increased risk of cardiovascular disease. However, this is more relevant to dietary intake than supplemental methionine. 

Caution: 

• Individual Health Conditions: Individuals with pre-existing health conditions, such as kidney or liver disorders, should exercise caution when considering methionine supplementation. methionine metabolism is closely linked to these organs, and excessive intake may exacerbate existing issues. 
• Allergic Reactions: Some individuals may be allergic or sensitive to methionine or its derivatives. Before starting any supplementation, it’s important to be aware of potential allergic reactions and consult with a healthcare professional if there are concerns. 

Pregnancy / Lactation

Pregnancy consideration: Insufficient data available 

Lactation: Excretion of the drug in human breast milk is unknown 

Pregnancy category: 

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence, these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category 

Pharmacology

Pharmacology: 

methionine is an essential amino acid, and its pharmacology primarily revolves around its role in protein synthesis, methylation reactions, and other biochemical processes in the body. Unlike drugs with specific pharmacological actions, methionine’s effects are part of the broader landscape of normal physiological functions. Here are critical aspects of the pharmacology of methionine: 

• Protein Synthesis: methionine is essential for the initiation of protein synthesis. It serves as the starting amino acid in the formation of polypeptide chains during translation. 
• Methylation Reactions: methionine is a precursor for S-adenosylmethionine (SAM), a cofactor involved in numerous methylation reactions. SAM is crucial for the methylation of DNA, RNA, proteins, and other molecules, playing a role in gene expression, neurotransmitter synthesis, and various cellular processes. 
• Antioxidant Properties: methionine and its derivatives contribute to antioxidant defenses. The sulfur-containing structure of methionine is important for the synthesis of glutathione, an essential antioxidant involved in protecting cells from oxidative stress. 
• Detoxification: methionine is involved in the synthesis of glutathione, which plays a central role in detoxifying harmful substances in the liver. This includes the detoxification of drugs, pollutants, and other xenobiotics. 
• Cofactor for Enzymes: methionine acts as a cofactor for certain enzymes involved in various metabolic pathways. It participates in reactions that contribute to the synthesis of important molecules in the body. 

Pharmacokinetics: 

Absorption 

methionine is absorbed in the small intestine during the process of digestion. It is taken up by the enterocytes, the cells lining the small intestine, and then enters the bloodstream. Absorption efficiency may be influenced by factors such as dietary composition and the presence of other amino acids. 

Distribution 

Once absorbed, methionine is distributed throughout the body via the bloodstream. It enters cells and tissues where it is utilized for various biological processes, including protein synthesis, methylation reactions, and antioxidant mechanisms. 

Metabolism 

methionine undergoes metabolic transformations within the body. One of its major metabolic pathways involves conversion to S-adenosylmethionine (SAM), a crucial methyl donor in various biochemical reactions. SAM is involved in methylation reactions, contributing to the regulation of gene expression, neurotransmitter synthesis, and other cellular processes. 

Elimination and Excretion: 

methionine and its metabolites are excreted from the body through various routes. The primary route is through the urine, but excretion may also occur through other pathways, such as bile and feces. 

Adminstartion

Administration: 

N/A 

Patient Information Leaflet

Patient information leaflet 

Generic Name: methionine 

Why do we use methionine? 

methionine, as an essential amino acid, plays several important roles in the body. 

• Protein Synthesis: methionine is a critical amino acid involved in the initiation of protein synthesis, playing a crucial role in the formation of polypeptide chains. 
• Methylation Reactions: methionine serves as a precursor for S-adenosylmethionine (SAM), a vital methyl donor involved in various methylation reactions, including the regulation of gene expression and protein modification. 
• Antioxidant Properties: methionine contributes to antioxidant defenses, protecting cells from oxidative stress. It is involved in the synthesis of molecules like glutathione, which plays a key role in neutralizing free radicals. 
• Liver Function Support: methionine is important for liver health, participating in the synthesis of phosphatidylcholine, a component of cell membranes crucial for proper liver function. 
• Detoxification: methionine is involved in the synthesis of glutathione, contributing to the detoxification of harmful substances, including drugs and environmental toxins. 
• Joint Health: methionine is a precursor to cysteine, essential for the synthesis of cartilage components like collagen, supporting joint health and connective tissue integrity.