Vancomycin: oral capsules for C. diff and the injected form explained

Vancomycin is an antibiotic that belongs to the group called glycopeptides. The manufacturer leaflet for the capsules says it works by eliminating certain bacteria that cause infections. It is a prescription-only medicine and is used in hospitals and in the community under specialist or GP direction.

It is not a first-choice antibiotic for everyday infections. Instead it is kept for specific roles: treating C. difficile infection of the bowel when taken by mouth, and treating serious infections caused by susceptible bacteria when given into a vein.

Because the same drug behaves very differently depending on how it is given, it helps to know which form you have been prescribed. Capsules or a liquid made up for swallowing act inside the bowel. A drip acts throughout the body and is carefully monitored.

The NHS describes C. diff as a type of bacteria that can cause diarrhoea and that often affects people who have been taking antibiotics. Symptoms include diarrhoea, a high temperature, loss of appetite, feeling sick and a stomach ache. It says treatment usually involves stopping any antibiotics you are on if possible and taking a new 10-day course of another antibiotic that can treat the infection.

NICE guideline NG199 sets out the choice for adults. For a first episode of mild, moderate or severe infection, the first-line antibiotic is vancomycin 125 mg by mouth four times a day for 10 days. If vancomycin is ineffective, fidaxomicin 200 mg twice a day for 10 days is the second-line option. For a relapse within 12 weeks fidaxomicin is listed, and for a recurrence more than 12 weeks later either vancomycin or fidaxomicin can be used. For life-threatening infection, specialists may use higher oral doses of vancomycin with intravenous metronidazole.

The capsule leaflet gives the recommended dose as 125 mg every 6 hours, with a higher dose of up to 500 mg every 6 hours in some cases, a usual duration of 10 days, and capsules swallowed whole with water. Take the full course even if you feel better. The NHS warns that stopping early could allow symptoms to come back.

NICE says it is not usually possible to judge that treatment has failed until day 7, because diarrhoea may take 1 to 2 weeks to resolve. The NHS says symptoms should improve a few days after starting but it may be 1 to 2 weeks before the infection clears completely, and to go back to the GP if you get worse, feel very unwell or symptoms return.

If C. diff returns two or more times, the NHS says a faecal microbiota transplant may be offered. NICE also says not to give antibiotics to prevent C. diff, and not to advise prebiotics or probiotics for prevention.

The leaflet for the infusion form says vancomycin is used by infusion, in all age groups, for serious infections of the skin and tissues below the skin, bones and joints, pneumonia, infection of the lining of the heart (endocarditis), infections of the central nervous system and blood infections linked to these. It is always given by medical staff in hospital, into a vein over at least 60 minutes, and never into a muscle.

The leaflet says the dose depends on your age, weight, the infection, how well your kidneys work, your hearing and other medicines. For adults the usual infusion dose is 15 to 20 mg for each kilogram of body weight, usually every 8 to 12 hours, and treatment may last a number of weeks. During treatment you might have blood tests, urine samples and possibly hearing tests to look for side effects. People who are elderly, pregnant or have kidney disorders, including those on dialysis, may need a different dose.

The infusion leaflet names several medicines that can interact, including gentamicin and other aminoglycosides, piperacillin with tazobactam, amphotericin B, cisplatin and anaesthetic agents, and says more frequent blood and kidney tests may be needed. It also notes that NSAIDs such as ibuprofen can increase the risk of kidney damage. The piperacillin with tazobactam leaflet says the same: taking the two together may increase the risk of kidney injury even if you have no kidney problems.

Redness of the upper body and face, a fall in blood pressure and itching are listed among the more common effects. If you notice flushing, wheeziness, rash or itching during a drip, tell the nurse straight away.

The leaflet says to talk to your doctor or pharmacist before taking capsules if you have a kidney disorder, an inflammatory bowel disorder, a hearing disorder, are elderly, or are receiving vancomycin for a long time. Long-term use may allow another type of infection to develop.

Allergic reactions are possible though serious ones are rare. Tell a doctor immediately about sudden wheeziness, difficulty breathing, redness on the upper body, rash or itching. Stop and seek urgent help for target-like patches with blisters, peeling skin, ulcers of the mouth, throat, nose, genitals and eyes, a widespread rash with fever and swollen glands, a red scaly rash with pustules, or chest pain that could signal a serious allergic reaction.

Because very little is absorbed from capsules, most people have few problems, but the leaflet lists common effects of the infusion form such as a fall in blood pressure, liver enzyme changes, rash, itching and kidney problems found on blood tests. Uncommon effects include hearing loss, and rare effects include tinnitus, dizziness, loss of balance and low blood cell counts.

Pregnant or breastfeeding women should ask a doctor or pharmacist for advice. The leaflet says the capsules should not affect driving.

C. diff spreads easily. The NHS advises staying at home until at least 48 hours after diarrhoea stops, washing hands regularly with soap and water because hand sanitiser does not kill it, cleaning the toilet and surrounding area with disinfectant after each use, washing soiled clothes and sheets separately at the highest possible temperature, and not sharing towels or flannels.

Drink plenty of fluids. NICE says people should be advised about fluids to avoid dehydration, preventing the spread of infection and seeking help if symptoms worsen rapidly. NICE also advises that a diagnosis of C. diff be recorded, so that it is taken into account before any future antibiotics are prescribed. Mention a past episode whenever you are offered a new antibiotic.

Treatment of C. diff in the community usually starts through the GP, with referral to hospital if the person is severely unwell or at risk of complications, as NICE describes. Private hospitals use vancomycin in the same way. The treatment pathway is similar in both sectors.