Cautionary Notes for Use of S-Adenosylmethionine
Pathology
S-adenosylmethionine (SAMe) is an endogenous molecule that is widely present in the body and is synthesized by cells.
Adenosylmethionine is formed by the action of adenosylmethionine synthase (this enzyme is produced in the liver and is a limited intermediate product of the liver) from methionine and ATP.
S-adenosylmethionine is an essential part of the following three main biochemical pathways: methylation, sulfation, and transamidation.
The normal function of these pathways is particularly important for the liver, as many metabolic reactions occur here.
In the methylation pathway, SAMe acts as a methyl donor (many substances and drugs require it for activation and/or elimination).
The methylation reaction is a necessary reaction for phospholipid synthesis, which is very important for the structure, fluidity, and function of cell membranes.
In the transamidation pathway, SAMe provides the amino propyl group, which is the source of polyamines.
The amino propyl group plays an important role in the production of anti-inflammatory substances, protein and DNA synthesis, cell replication, and liver tissue renewal.
In the sulfation pathway, S-adenosylmethionine forms sulfur-containing compounds, including reaction products used for detoxification and as the precursor of glutathione (GSH).
Glutathione is very important in many metabolic processes and cellular detoxification.
The conversion of S-adenosylmethionine to glutathione requires folic acid, vitamin B12, and pyridoxine (B6).
Usually, the liver produces sufficient SAMe, but when liver diseases or toxic substances occur, the internal conversion of glutathione becomes insufficient.
Exogenous SAMe has the effect of increasing the levels of glutathione in the liver and red blood cells and/or preventing its deficiency.
S-adenosylmethionine can inhibit hepatocyte apoptosis caused by ethanol or bile acids.
Indications
S-adenosylmethionine is most commonly used as an adjunctive treatment for liver diseases (such as chronic hepatitis, fatty liver, cholangitis, and trisomy disease in cats).
S-adenosylmethionine also has certain effects on osteoarthritis and can be used to treat liver toxicity induced by acute liver toxins (such as acetaminophen toxicity) and animals that have been using drugs with potential liver toxicity for a long time.
Excessive dosage
S-adenosylmethionine is very safe.
The LD50 for rodents exceeds 4.65 g/kg.
Toxicity studies in cats and dogs at conventional doses show no adverse reactions.
In cases of excessive use, intestinal reactions can be observed, but usually no treatment is required.
Drug interactions
Theoretically, the concurrent use of SAMe with tramadol, pethidine, meperidine, pentazocine, monoamine oxidase inhibitors including seligiline, selective 5-hydroxytryptamine reuptake inhibitors (such as fluoxetine), or other antidepressants (such as amitriptyline, clomipramine) can lead to an additive effect on 5-hydroxytryptamineergic neurons.
Dosage
Dogs and Cats:
Daily dosage based on the animal's weight:
5.5 kg: 1 tablet of 90mg.
5.5 - 11 kg: 2 tablets of 90mg (or 1 tablet of 225mg).
11 - 16 kg: 1 tablet of 225mg.
16 - 29.5 kg: 2 tablets of 225mg.
29.5 - 41 kg: 3 tablets of 225mg.
Over 41 kg: 4 tablets of 225mg.
The daily dose can also be calculated based on 8mg/kg of body weight, and then rounded up to the nearest quality of tablet or combined with different specifications.
It should be taken on an empty stomach, at least 1 hour before eating.
If more than 1 tablet is given, the total daily dose can be divided and administered twice a day.
According to the needs of the animals, the dosage can be gradually increased or decreased.
Adjuvant treatment for chronic hepatitis:
Dog: 17-20 mg/kg per day or a higher dose, administered on an empty stomach.
Cat: 200 mg per day, administered on an empty stomach.
