Methionine Tablets 250mg

1. Name Of The Medicinal Product

Methionine Tablets 250mg

2. Qualitative And Quantitative Composition

Methionine (DL) 250 mg

For excipients see section 6.1.

3. Pharmaceutical Form

Tablet

4. Clinical Particulars

4.1 Therapeutic Indications

Methionine is given, by mouth, for the treatment of paracetamol overdose if n-acetyl cysteine is not available or if the patient cannot tolerate n-acetyl cysteine.

4.2 Posology And Method Of Administration

Paracetamol Overdose: Give within 10 hours of paracetamol ingestion, subsequent to any emesis being induced.

Adults and the elderly: 2.5g (10 tablets) every 4 hours to a maximum of 10g

Children (up to 6 years): 1g (4 tablets) every 4 hours to a maximum of 4g

Children (6 years and over): As adult dose

4.3 Contraindications

Methionine should not be used for the treatment of paracetamol overdosage if more than 10 hours have elapsed since the time of the overdose.

Do not use in patients with metabolic acidosis.

4.4 Special Warnings And Precautions For Use

Use methionine with care in patients with established liver disease as hepatic encephalopathy may be precipitated.

Use with caution in patients with schizophrenia as daily methionine doses of 10 to 20g have been reported to precipitate acute exacerbation of symptoms in such patients.

4.5 Interaction With Other Medicinal Products And Other Forms Of Interaction

The anti-parkinsonism effects of levodopa may be reduced by methionine, especially if large doses of methionine are given.

Methionine may be adsorbed by activated charcoal and the effect of oral methionine may be reduced if they are given together. It is recommended that activated charcoal should be cleared from the stomach or avoided if methionine is to be used.

4.6 Pregnancy And Lactation

The safety, in human pregnancy or during lactation, of the ingestion of higher levels of methionine than would normally be encountered in the diet, has not been established. Methionine should only be used during pregnancy or lactation if the benefit of its use has been weighed against any potential risks.

4.7 Effects On Ability To Drive And Use Machines

Patients should be advised that methionine may cause drowsiness and their ability to drive or operate machinery may be affected.

4.8 Undesirable Effects

Oral doses of methionine may cause nausea, vomiting, drowsiness and irritability. Daily doses of 6 to 20g can cause neurological changes and precipitate Encephalopathy in patients with hepatic cirrhosis especially if portal hypertension is present.

4.9 Overdose

Overdosage with methionine may be associated with the appearance of the above mentioned side-effects (nausea, vomiting, drowsiness, irritability). As methionine forms part of the normal diet, no specific recommendations for treatment of overdose are available. General support measures may be appropriate.

5. Pharmacological Properties

5.1 Pharmacodynamic Properties

Methionine is an essential amino acid that plays a vital role in intermediary metabolism. It is the primary donor of methyl groups for biosynthetic reactions but must first be converted to s-adenosylmethionine, its active moiety. It is then involved in the transmethylation of nucleic acids, proteins, lipids and other metabolites and in the synthesis of choline. Methionine is converted to cysteine, a precursor of glutathione, in the liver. Methionine is thought to prevent liver damage in paracetamol overdose by facilitating glutathione synthesis. Methionine has a lipotropic action which prevents the development of fatty liver and it also stimulates pancreatic insulin release.

5.2 Pharmacokinetic Properties

Absorption: Methionine is absorbed from the gastro-intestinal tract. Absorption is unpredictable in patients who are vomiting.

Half-Life: Not known

Distribution: Not known

Metabolism: Methionine is metabolised via s-adenosylmethionine to homocysteine. About 80% is further converted to cystathionine, cysteine, taurine and inorganic sulphate.

Excretion: Methionine is excreted in the urine as an inorganic sulphate.

5.3 Preclinical Safety Data

None stated

6. Pharmaceutical Particulars

6.1 List Of Excipients

Alginic acid

Starch maize

Tragacanth powdered

Magnesium stearate

Talc

Coating:

Acacia syrup solution

Talc

Light calcium carbonate

Acacia mucilage

Titanium dioxide 1700 ansteads

Opaglos AG 7350 containing :

Beeswax white

Carnauba wax yellow

Polysorbate 20

Sorbic acid (E200)

Purified water

Opacode S-1-8100HV Black containing :

Industrial Methylated Spirits

Shellac (E904)

Iron Oxide Black (E172)

Purified Water

2-Ethoxyethanol

Soya Lecithin MC Thin (E322)

Antifoam DC 1510

6.2 Incompatibilities

None known

6.3 Shelf Life

36 months

6.4 Special Precautions For Storage

Store at room temperature

6.5 Nature And Contents Of Container

Pigmented polypropylene container with tamper-evident closure of low density polyethylene. Containers hold either 50, 200 or 250 tablets

6.6 Special Precautions For Disposal And Other Handling

None stated

7. Marketing Authorisation Holder

UCB Pharma Ltd

208 Bath Road

Slough

Berkshire

SL1 3WE

8. Marketing Authorisation Number(S)

PL 00039/0553

9. Date Of First Authorisation/Renewal Of The Authorisation

4 July 2005

10. Date Of Revision Of The Text

Approved: October 2009

11 DOSIMETRY (IF APPLICABLE)

Not applicable

12 INSTRUCTIONS FOR PREPARATION OF RADIOPHARMACEUTICALS (IF APPLICABLE)

Not applicable