How does it work?

Zyvox tablets, oral solution and infusion all contain the active ingredient linezolid, which belongs to a new class of antibiotics called the oxazolidinones. It is used to treat infections caused by bacteria.

Linezolid works by interfering with the production of proteins that bacteria need to multiply and divide. This inhibits the ability of the bacteria to grow and replicate and therefore stops the spread of bacterial infection. The remaining bacteria subsequently die or are killed by the immune system.

Linezolid can only be used to treat infections with a specific sub-group of bacteria called Gram positive bacteria.

Linezolid has a different mechanism of action to all the other classes of antibiotics. This means it can be used to treat Gram positive bacterial infections that are resistant to other antibiotics. An example of this is infection with the 'superbug' MRSA (methicillin-resistant staphylococcus aureus). Such bacterial infections have become more common, particularly in hospitals, due to increasing resistance of bacteria to antibiotic treatment. As linezolid works in a different way to other antibiotics, it may provide doctors with a new line of attack for these types of infections.

To make sure the bacteria causing an infection are susceptible to linezolid your doctor may take a tissue sample, for example a swab from the skin, or a sputum sample.

What is it used for?

• Complicated skin and soft tissue infections.
• Pneumonia.

Warning!

• This medicine may cause dizziness and so may affect your ability to drive or operate machinery safely. Do not drive or operate machinery until you know how this medicine affects you and you are sure it won't affect your performance.
• While taking this antibiotic you should avoid consuming large amounts of foods and drink that contain high levels of the amino acid tyramine, as this can cause a dangerous rise in blood pressure. Tyramine-rich foods include matured cheeses, yeast extracts (eg Oxo, Bovril, Marmite), undistilled alcoholic drinks (particularly draught beer and wine) and fermented soya bean products (eg soy sauce).Ask your pharmacist for more information. If you develop athrobbing headache after eating ordrinking, tell your doctor or pharmacist.
• This medicine may cause a decrease in the normal amount of blood cells in the blood. Decreased red blood cells or haemoglobin can result in anaemia, decreased white blood cells can increase susceptibility to infections and decreased numbers of cells called platelets can cause problems with blood clotting. For this reason, you will need to have a weekly blood test to monitor the composition of your blood while taking this antibiotic. The following groups of people may need to be more closely monitored: people who already have anaemia, low white blood cell counts or low platelet counts, people taking other medicines that can reduce blood counts, levels of platelets or haemoglobin, people with impaired kidney function and people who receive more than 10-14 days of treatment with this medicine.
• Antibiotics can sometimes cause inflammation of the bowel (colitis). For this reason, if you get diarrhoea either during or after taking this medicine, particularly if it becomes severe or persistent or contains blood or mucus, you should consult your doctor immediately.
• You should consult your doctor as soon as possible if you experience any changes in your vision, for example, blurred vision, tunnel vision, difficulty seeing fine detail, or changes in your colour vision, while taking this antibiotic.
• Unless your doctor tells you otherwise, it is important that you finish the prescribed course of this antibiotic medicine, even if you feel better or it seems the infection has cleared up. Stopping the course early increases the chance that the infection will come back and that the bacteria will grow resistant to the antibiotic.
• The manufacturer states that this antibiotic should not normally be used for longer than 28 days, as they have not studied its safety and effectiveness when used for longer than this. If for any reason your doctor has asked you to keep taking this antibiotic for longer than 28 days, your eyesight should be regularly monitored.

Use with caution in

• Decreased kidney function.
• People having haemodialysis for kidney failure.
• Severely decreased liver function.
• Uncontrolled high blood pressure (hypertension).
• Tumour of the adrenal gland (phaeochromocytoma).
• Tumour in the intestine called a carcinoid tumour.
• Thyrotoxicosis.
• Bipolar affective disorder (manic depression).
• Mental disorder with symptoms of schizophrenia and mood disorder.
• Acute states of confusion.
• Anaemia.
• People with low numbers of white blood cells in their blood.
• People with low numbers of cells called platelets in their blood (thrombocytopenia).

Not to be used in

• People who have taken a monoamine-oxidase inhibitor medicine in the last 14 days (see below for more information).
• Breastfeeding.
• Zyvox oral solution contains aspartame, which is a source of phenylalanine, and so is not suitable for people with phenylketonuria.
• Zyvox oral solution also contains sucrose and so is not suitable for people with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency.
• This antibiotic is not recommended for children and adolescents under 18 years of age, as there is no information regarding its safety and efficacy in this age group.

This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

• The safety of this medicine for use during pregnancy has not been established. It is not recommended for use in pregnancy unless considered essential by your doctor. Seek medical advice from your doctor.
• This medicine may pass into breast milk. Mothers who need to take this medicine should not breastfeed their infants during treatment. Discuss with your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

Common (affect between 1 in 10 and 1 in 100 people)

• Headache.
• Diarrhoea.
• Nausea.
• Yeast infection of the moist areas of the body, especially the vagina and mouth (candidiasis).

Uncommon (affect between 1 in 100 and 1 in 1000 people)

• Decreased numbers of red blood cells, haemoglobin, white blood cells or platelets in the blood
• Inflammation of the vagina (vaginitis).
• Difficulty in sleeping (insomnia)
• Pins and needles sensations (paraesthesia) or numbness.
• Blurred vision.
• Sensation of ringing or buzzing in the ears (tinnitus).
• Inflammation of the wall of a vein with a blood clot forming in the affected segment of vein (thrombophlebitis).
• Inflammation of the pancreas (pancreatitis).
• Inflammation of the stomach (gastitis).
• Disturbances of the gut such as constipation, vomiting, abdominal pain, dry mouth, indigestion,
• Discoloration of the tongue.
• Skin reactions such as rash, itching.
• Fever.
• Fatigue.

Rare (affect between 1 in 1000 and 1 in 10,000 people)

• Increased heart rate (tachycardia).
• Sudden loss of brain function with full recovery within 24 hours (transient ischaemic attack).
• Kidney failure.

Frequency unknown

• Inflammation of the large intestine (colitis).
• Elevated levels of lactic acid in the blood (lactic acidosis).
• Swelling of the optic nerve which results in blurring of vision (optic neuritis).
• Decreased amount of sodium in the blood (hyponatraemia).
• Discoloation of the teeth.
• Hair loss.
• Severe blistering skin reactions, eg Stevens-Johnson Syndrome, toxic epidermal necrolysis.

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, ask your doctor or pharmacist before taking any new medicines while taking this one, so they can check that the combination is safe.

This medicine must not be taken by people who are taking monoamine oxidase inhibitor medicines (MAOIs - used to treat depression or Parkinson's disease), or who have taken an MAOI medicine in the previous two weeks. MAOIs are:

• the antidepressants phenelzine, isocarboxacid or tranylcypromine
• moclobemide for depression
• selegiline or rasagiline for Parkinson's disease.

Linezolid should not be taken by people taking any of the following medicines unless the individual is under close medical observation and their blood pressure is monitored:

• SSRI antidepressants, eg fluoxetine, paroxetine
• tricyclic antidepressants, eg amitriptyline, imipramine
• triptans for migraine, eg sumatriptan, almotriptan, rizatriptan
• decongestants, eg pseudoephedrine, phenylpropanolamine, ephedrine, phenylephrine (these are often found in cold and flu remedies)
• medicines that open the airways, eg salbutamol, salmeterol, terbutaline
• amphetamines
• methylphenidate
• adrenaline
• noradrenaline
• pethidine
• buspirone
• dopamine
• dobutamine.

Other medicines containing the same active ingredient

There are currently no other medicines available in the UK that contain linezolid as the active ingredient.