The patient had a to penicillin

Antibiotics are used to treat or prevent some types of bacterial infection. They kill bacteria or prevent them from reproducing and spreading.

Antibiotics aren't effective against viral infections. This includes the common cold, flu, most coughs and sore throats.

Antibiotics aren't routinely prescribed for mild bacterial infections. This is because the immune system can usually clear these on it's own.

When are antibiotics used?

Antibiotics may be used to treat bacterial infections that:

• are unlikely to clear up without antibiotics
• could infect others unless treated
• could take too long to clear without treatment
• carry a risk of more serious complications

Antibiotics to prevent infection

Antibiotics are sometimes given as a precaution to prevent an infection. This is known as antibiotic prophylaxis.

Surgery

Antibiotic prophylaxis is normally recommended if you're having surgery in a certain area. This is because there could be a higher risk of infection.

Your surgical team will be able to tell you if you need antibiotic prophylaxis.

People vulnerable to infection

Antibiotics may be recommended for people who are more vulnerable to infection. This includes:

• people aged over 75 years
• babies less than 72 hours old with a confirmed bacterial infection
• babies with a high risk of developing a bacterial infection
• people with heart failure
• people who have to take insulin to control their diabetes
• people with a weakened immune system

Bites or wounds

Antibiotic prophylaxis may be recommended for a wound that has a high chance of becoming infected. This could be an animal or human bite, for example, or a wound that has come into contact with soil or faeces.

Medical conditions

There are several medical conditions that make people particularly vulnerable to infection. This makes antibiotic prophylaxis necessary.

The spleen plays an important role in filtering out harmful bacteria from the blood. If your spleen doesn't work properly, this means antibiotics can help prevent infection.

People more vulnerable to infection include those:

• who've had their spleen removed
• having chemotherapy for cancer
• with the blood disorder sickle cell anaemia

Recurring infection

Antibiotic prophylaxis may also be recommended for a recurring infection, like:

Types of antibiotics

There are many different types of antibiotic. Most can be put into 6 different groups.

Penicillins

These are widely used to treat a variety of infections, including:

• skin infections
• chest infections
• urinary tract infections

Cephalosporins

These can be used to treat a wide range of infections. Some are also effective for treating more serious infections, like:

Aminoglycosides

These are usually used in hospital to treat very serious illnesses like septicaemia. This is because they can cause serious side effects like hearing loss and kidney damage.

Aminoglycosides are usually given by injection. They may also be given as drops for some ear or eye infections.

Tetracyclines

These can be used to treat a wide range of infections. They are commonly used to treat moderate to severe acne and rosacea.

Macrolides

These can be particularly useful for treating lung and chest infections.

Macrolides are used as an alternative for people with a penicillin allergy. They can also be used to treat penicillin-resistant strains of bacteria

The phrase �allergic to penicillin� is commonly seen in medical notes and on medicine charts. The diagnosis of �penicillin allergy� is often simply accepted without obtaining a detailed history of the reaction. It has been reported that a significant percentage of patients labelled as �penicillin allergic� are not truly allergic to the drug. As a result, penicillins are unnecessarily withheld from these patients, which may subsequently affect their clinical outcomes.

What is the True Incidence of �Penicillin Allergy�?
General hypersensitivity reactions (e.g. rashes) to penicillin occur in between 1 and 10% of exposed patients but true anaphylactic reactions (which can be fatal) occur in less than 0.05% of treated patients. Please note that patients who have a vague history of symptoms or gastro-intestinal intolerance are probably not truly allergic to penicillins.

Who is at risk?
Patients with a history of atopic allergy (e.g. asthma, eczema, hay fever) are more likely to be allergic to penicillins.

Who should not be prescribed or administered penicillins?
Individuals with a history of Type I allergy clinically recognisable by features of urticaria, laryngeal oedema, bronchospasm, hypotension or local swelling within 72 hours of administration, or development of a pruritic rash (even after 72 hours) should NOT receive a penicillin.

Are there situations where cephalosporins or other beta-lactam antibiotics can be prescribed for patients with penicillin hypersensitivity?
Clinical studies suggest that the incidence of cross-reactivity to cephalosporins in penicillin-allergic patients is around 10% but this is thought to be an overestimate. The true incidence of cross-sensitivity is uncertain. Second and third generation cephalosporins are unlikely to be associated with cross reactivity as they have different side chains to penicillin.

• Patients with no evidence of Type I allergy to penicillin may be treated with any cephalosporin or beta lactam antibiotic for infections of any severity.

• Patients with symptoms suggestive of a Type I allergy should avoid cephalosporins and other beta-lactam antibiotics for mild or moderate infections when a suitable alternative exists. In life threatening infections, when use of a non-cephalosporin antibiotic would be sub-optimal, consider giving, under observation, a second or third generation cephalosporin (e.g. cefuroxime, ceftriaxone, ceftazidime).  If necessary seek advice from ID or Microbiology.

What about other types of antibiotics?
Tetracyclines (e.g. doxycycline), quinolones (e.g. ciprofloxacin), macrolides (e.g. clarithromycin), aminoglycosides (e.g. gentamicin) and glycopeptides (e.g. vancomycin) are all unrelated to penicillins and are safe to use in the penicillin allergic patient.

Prescribing Issues
Always identify and document the nature of the reported allergy and drug name on the medicine chart and in the medical notes. The prescriber has the primary responsibility for ensuring that the allergy/sensitivity details are completed on all relevant medicine charts and medical notes.

What should be prescribed for truly penicillin allergic patients?

Urinary Tract InfectionsFemale Lower UTITrimethoprim or nitrofurantoinFemale Upper UTICo-trimoxazole + gentamicinMale UTITrimethoprim or ciprofloxacin
Upper Respiratory Tract InfectionsSinusitisDoxycyclineTonsillitisErythromycin or clarithromycinOtitis MediaErythromycin or clarithromycin
Lower Respiratory Tract InfectionsCommunity Acquired Pneumonia (non-severe)DoxycyclineCommunity Acquired Pneumonia (severe)IV Levofloxacin then oral doxycyclineAspiration or Hospital Acquired Pneumonia (severe)IV Vancomycin + metronidazole + gentamicin (and seek advice)Aspiration or Hospital Acquired Pneumonia (non-severe)Co-trimoxazole (+metronidazole if aspiration suspected)Infective Exacerbation of COPDDoxycycline
Peritonitis/Biliary Tract/Intra-abdominal InfectionsSevereIV Vancomycin + metronidazole + gentamicin (and seek advice)Step down to oralCotrimoxazole
Skin InfectionsCellulitis (see separate protocol)DoxycyclineAnimal bitesMetronidazole + doxycyclineSurgical ProphylaxisSee separate protocol

Click here for information on which antibiotics should be avoided in penicillin allergy, those that should be used with caution, and those that are safe.

How is penicillin given to a patient?

What happens during a penicillin reaction?

Which disease is caused by penicillin?

What is the penicillin used for?