by Jane Grimshaw

Created on: July 25, 2011   Last Updated: July 26, 2011

Methionine, which is sold under the brand names of Methio-Form and Ammonil, belongs to a group of compounds called lipotropics that enable the liver to process lipids (fats). It is an essential amino acid that needs to be obtained from the diet because it cannot be made by the body. It also provides the body with sulphur and helps to prevent certain disorders of the skin, hair and nails. Methionine is generally used as a urinary acidifier that can treat and prevent certain types of urinary stones in dogs. It helps to reduce the chances of stones in dogs by chelating heavy metals, such as mercury, lead and cadmium, and removing them from the body. Methionine can also be used to treat conditions in a variety of other animals, such as cats, rats, pigs and horses, and humans.

Dosage instructions

Methionine can only be bought by prescription and the usual dosage is half a tablet per 4.5 kg of your dog’s body weight, given once or twice daily. The dosage may need to be adjusted in certain cases, however, to enable your dog to maintain a consistent urine pH of below 6.6. It is important to administer the medication at regular intervals, but if you do forget to give your dog one of its doses then the dose should be administered as soon as you remember - but never give more than one dose at the same time. It is also best to give your dog food with the medication, as this can increase its effectiveness and reduce the possibility of side effects. The duration of treatment will depend on the condition being treated, the severity of the condition, how well your dog responds to it and whether the animal develops any side effects. Unless advised otherwise by your vet, you should make sure that your dog completes the prescribed medication, even if it does appear to be better, to prevent a relapse from occurring.

Allergic reactions and other side effects

Methionine can unfortunately cause some unpleasant side effects, such as swelling of the face, pale gums, loss of appetite, vomiting and diarrhoea, seizures, and in some cases coma may even occur. If your dog does display any of these symptoms, you should stop administering the medication and consult your vet immediately. Methionine should also be used with caution if your dog suffers from kidney failure, liver or pancreatic disease.      

Drug interactions

Methionine can interact with other medications too, including vitamin supplements; so don’t forget to tell your vet if your dog is on any other medication. Methionine is also known to increase the urinary excretion of quinidine by acidifying the urine. Aminoglycoside antibiotics used to treat urinary tract infections work best in alkaline conditions, and urinary acidification from using methionine can reduce its effectiveness. If your dog is on a diet that acidifies the urine, you should not use methionine.

Conclusion

It appears that methionine is actually more important to canine health than many people realise, as it is essential for absorption, transportation and bioavailability of zinc and selenium in the body. Cysteine, taurine and carnitine also require adequate quantities of methionine for their synthesis. Some recent studies have even highlighted the fact that methionine can slow down the development of age-related cataracts.

During treatment with methionine, your dog’s urine pH and blood pH should be monitored regularly to ensure that the methionine is working properly and not having any adverse effects on your dog. If you are at all worried about anything during treatment, you should not hesitate to discuss the concerns with your vet.

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