Methionine (Oral)


Also known as Racemethionine, Methionine is an amino acid which is essential for certain functions of the body. Crucial to the formation of new blood vessels, Methionine has been shown to be effective in treating Parkinson's disease, depression, alcoholism, schizophrenia, allergies and asthma, when it is used in conjunction with other medications.

However, Methionine can also be used to increase the acidity of urine. When urine comes into contact with the skin, it can cause irritation and discomfort, particularly if it is in contact with the skin for a significant length of time. Continuous irritation can lead to broken skin, bleeding and increases the risk of an infection occurring.

If patients have limited bladder control or a complete loss of bladder control, Methionine may be used to alter the pH balance of their urine. By increasing the acidity of the urine, it will cause less irritation if and when it comes into contact with the skin. In addition to this, Methionine can be used to reduce the smell of urine if a particularly potent odor is present when the patient urinates.

As well as being used to treat adult patients, Methionine may be used to increase the urine acidity of infants. If a child is experiencing severe diaper rash, increasing urine acidity can help to prevent further irritation. Whilst topical medications may be used to treat diaper rash, Methionine can be used to prevent any further irritation from occurring.

Conditions Treated

  • Used to relieve skin irritation caused by contact with urine

Type Of Medicine

  • Urine acidifier

Side Effects

Although patients can experience adverse effects when they are taking any type of medicine, Methionine has been associated with only a few side-effects. Typically, these are more prominent when patients first start taking Methionine but may decrease over time, particularly if the patient's body becomes accustomed to the medication.

When patients take Methionine, they may notice the following adverse effects:

  • Nausea
  • Drowsiness
  • Vomiting

If the above side-effects diminish over time and are fairly mild, the patient may not require any additional medical treatment for them. However, if the patient's side-effects are severe or continuing, they should seek medical help.

In addition to this, patients should obtain medical advice or assistance if they experience any other adverse effects when they are taking Methionine as a urine acidifier.


If patients are prescribed Methionine, their dose will depend on their age, their medical history and the type of medication they are given.

If adults are prescribed Methionine capsules, for example, they are usually instructed to take 200mg, three to four times per day. For pediatric patients, a smaller dose of 200mg per day is typical. If necessary, the contents of the capsule may be added to a glass of fruit juice, water, warm milk or formula.

However, Methionine can be prescribed as an oral solution and it may be easier for infants to take this form of medication. For patients between the ages of two to six months, 75mg may be given three times per day, usually for a period of three to five days. If patients are between the ages of six and fourteen months, they are usually prescribed 75mg, four times per day, for a period of three to five days. Alternatively, patients over the age of fourteen months can be prescribed 200mg, three to four times per day.

If patients are prescribed Methionine as an oral solution, a medicine spoon, measuring cup or oral syringe should be used to measure their dose of medication. Standard household spoons are unlikely to provide an accurate measurement and the patient may not be given the correct dose if these type of spoons are used.

As well as being available as an oral solution and in capsule format, Methionine can also be prescribed as a tablet. However, Methionine tablets are only usually prescribed to adult patients. In this format, patients are usually instructed to take 500mg, three to four times per day.

Before taking Methionine, patients should tell their physician if they are following any special diets or if they have a restricted food intake.

In most cases, Methionine should be taken with food or just after consuming a meal.

Although Methionine should be taken in accordance with a physician's instructions, patients may occasionally forget to take a dose of medication. If so, they should take it as soon as they remember to do so. However, if their next dose of medication is due relatively soon, patients should skip the missed dose and continue taking their medication at normal. Patients should not take or be given an extra or double dose of Methionine, even if an earlier dose has been missed.

If patients or their caregivers are unsure how to use Methionine or when to take the medication, they should obtain medical advice from a physician or pharmacist.

Potential Drug Interactions

Before treatment with Methionine is started, the patient's physician should be told if the patient is taking any other medicines, vitamins or supplements. As some medicines can interact with one another, it may not be appropriate to take certain medicines in conjunction with Methionine.

Similarly, patients should obtain medical advice before using any new medicines, supplements or vitamins, once they have started taking Methionine.


If the patients has any other health problems, their physician should be informed before Methionine is prescribed. There are some conditions which can affect treatment with Methionine and these may include:

When patients are taking Methionine, they should notice a reduction in their symptoms fairly quickly. However, if the patient's skin rash or skin irritation has not improved within ten days of taking the medicine, they should seek further medical advice.

Currently the effects of Methionine on pregnant patients are unknown. Whilst harmful effects associated with Methionine have not been documented, this medication could still present a risk and may cause harm to an unborn fetus. Due to this, Methionine may not be prescribed to patients who are pregnant. If patients are pregnant, they must inform their physician before taking this medicine.

If patients become pregnant when using Methionine, they should notify their physician straight away.

Although some medications can be excreted in breast milk, it is not known if Methionine is transferred in this way or if it would pose a risk to an infant. Due to this, patients may be instructed not to breastfeed whilst taking Methionine and should obtain medical advice before doing so. As medications can remain in the system for some time, patients should not breastfeed soon after taking their final dose of Methionine as the medication could still pose a risk to the infant.

Before taking Methionine, patients should tell their physician if they have any existing allergies. This includes allergies to chemicals, medicines, preservatives, animals, dyes and any other substances. In rare cases, patients may experience an allergic reactions when taking Methionine and, if so, they will require emergency medical treatment. The symptoms of an allergic reaction can take the following form:

  • Itching
  • Difficulty breathing
  • Hoarseness
  • Rash on the skin
  • Difficulty swallowing
  • Swelling, which may affect the lips, tongue, mouth, throat, hands or face
  • Gasping for breath


When keeping medication at home, it's vital that patients or their caregivers keep the medicine in a safe location. Using a locked medicine cabinet or lockable medicine box may help to prevent children and/or pets from gaining access to Methionine.

If the medication is ingested by someone who isn't the intended patient or if the medication is taken in too high a dose, patients or their caregivers should call 911, access help from their nearest Emergency Room or contact a Poison Control Center immediately.

To store Methionine properly, patients should follow the medication guide and the manufacturer's instructions. Whilst most forms of Methionine can be kept at room temperature, some may need to be refrigerated. Similarly, Methionine should be protected from light, heat and moisture and should not be stored in environments which are subject to extreme temperatures.

If patients are advised to stop taking Methionine or if the medication reaches its use-by date, it should be disposed of carefully. It is not appropriate to throw medication out with normal household waste as it may pose a risk to other people. Instead, patients or their caregivers should contact a physician's office or pharmacist and make use of a specialist medicine disposal service.


If the skin is exposed to urine, it can cause painful and uncomfortable symptoms. Patients may complain of a stinging or burning sensation on the skin and irritation may worsen over time. If effective treatment isn't implemented, the skin may swell, break or develop an infection.

While urine should always be removed from the skin as quickly as possible, Methionine can be used to prevent irritation from occurring when the skin does come into contact with urine. By changing the urine's pH levels and making it more acidic, Methionine reduces the effect of the urine on the skin and, therefore, prevents irritation from occurring.