Antibiotics are prescribed to treat bacterial infections, most commonly those related to the ear, nose and throat. They are not effective for use against viral infections. 

  1. Prescribed to treat bacterial infections.
  2. Ineffective against infections caused by viruses.
  3. Should only be used when necessary.

If you are concerned you may have an infection, and you would like to speak to a registered clinician, you can make an appointment using our online video consultation service between 9.30am-4.30pm, Monday to Friday. 

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What are antibiotic medications?

Antibiotic medications are used to treat bacterial infections that are not likely to clear up on their own. They may also be used for bacterial infections that carry additional risks, or are likely to take a prolonged amount of time to clear without them. In rare cases, some people may be offered them as a preventative measure; for example, to ward off infection after surgery. 

There are many forms of bacterial infection, and they range from mild to severe in nature. Although they are effective, they may not work in all circumstances. Some of the most common or noteworthy bacterial infections that antibiotics treat include bronchitis, pneumonia, chlamydia and kidney infections.

What is bronchitis?

Bronchitis is an infection of the main airways of the lungs. When the airways become infected, inflammation develops, causing symptoms that include a sore throat, headaches, coughing, a blocked nose, aches and pains, fever, shortness of breath, wheezing and fatigue. Bronchitis can be caused by a viral or a bacterial infection, but antibiotics are only effective against a bacterial infection of the condition.

The body is able to clear up most acute infections itself, alongside the use of painkillers and over the counter medications to manage symptoms. However, if you have a cough that lasts for three weeks, a fever that persists for more than three days, are coughing up blood, getting recurring bronchial infections or have an underlying condition (a heart condition or asthma for example), you should speak to your doctor. Chronic infections (infections that last for months) require lifestyle changes in order to regulate symptoms, such as quitting smoking, eating a healthy diet and getting sufficient exercise.

What is pneumonia? 

Pneumonia is an infection of the lungs, or more specifically the small air sacs found at the end of the lung’s breathing tubes. Pneumonia can be a serious infection that requires a doctor’s visit if it’s suspected. In more severe cases, you should seek immediate medical attention; for instance, if you are having trouble breathing, experiencing chest pain or confusion. Milder symptoms include coughing up blood, headaches, joint or muscle pain, tiredness and wheezing, with disorientation is more likely in the elderly. Pneumonia can affect any age at any time of year but is more prevalent in the very young and elderly during the autumn and winter months, for whom it is also often more serious. 

What causes pneumonia?

The majority of pneumonia cases are triggered by the bacteria Streptococcus pneumoniae, although other bacteria, viruses and even fungi can be causes. Diagnosing pneumonia can be done with a doctor or nurse asking you what your symptoms are, checking your temperature and listening to your chest, but tests to rule out other conditions, such as colds, flus and asthma, may also be required. Milder cases can be dealt with by getting plenty of bed rest, drinking fluids and taking a course of antibiotics, but at risk groups may require hospital admission.

Complications related to pneumonia are serious and include blood poisoning, pleurisy ( inflammation of the tissue between the lungs and ribs that can lead to respiratory failure) and lung abscesses. The effects of pneumonia can last for as long as six months in more severe cases, but you should notice a slow and steady improvement during recovery. Lifestyle changes, such as quitting smoking, can also be of significant benefit during this time.

What is chlamydia? 

Chlamydia is the most common sexually transmitted infection of teenagers the UK. It is caused by unprotected sex with someone who has the condition. Symptoms of chlamydia include pain during urination and discharge from the penis, vagina or anus. In women, it may also include  abdominal pain and bleeding during sex, while men can experience pain and swelling of the testicles. In many cases, however, symptoms do not appear. This can be dangerous as, although it usually clears up with a short course of antibiotics, it can spread to other parts of the body, causing long term damage. 

Testing for chlamydia usually requires a swab or urine test, which can be carried out at a GP surgery or GUM clinic. People under 25 can also get tested at colleges, pharmacies and contraceptive clinics via the NCSP (National Chlamydia Screening Programme). Treatment for chlamydia requires a course of antibiotics that can last either one day or one week, although rare cases may require longer treatment. You should avoid having sex for one week after taking the one-day treatment and during the entirety of the weeklong treatment. You can prevent chlamydia by using condoms and refraining from sharing sex toys.

What is a kidney infection?

A kidney infection is an unpleasant condition that is caused by bacteria travelling from the bladder to one or both of the kidneys. It is not a serious condition if caught early, but permanent damage to vital organs can occur if it’s left untreated. Kidney infections are caused by bladder infections, usually E. coli, travelling up the tubes that eliminate urine and into the kidneys. They are more common in women (particularly younger women), than men, but can occur at any age. Kidney infections can also be triggered by cystitis, which is a bladder infection that may cause symptoms including cloudy and strong smelling urine, pain when urinating and feeling generally unwell. If these symptoms do not improve, you should seek medical advice from your doctor. 

How is a kidney infection diagnosed?

If an infection spreads to the kidney, it may trigger a fever, shivering, feeling sick and pain in the side or back.  A doctor will carry out a urine test to establish if you also have a urinary tract infection (UTI) such as cystitis, and they will ask you about your symptoms. If you’re a man and it’s determined that you have UTI, a doctor will refer you to a urologist for further examination. 

In terms of treatment, in most cases, kidney infections require an immediate course of antibiotics to prevent the infection from damaging the kidneys and getting into the bloodstream. Painkillers may also help to manage symptoms. If you’re particularly susceptible to the effects of an infection (for instance, if you have a long-term health condition or are pregnant), hospital admission may be required, and treatment with antibiotics via a drip. After a course of antibiotics, you should recover around two weeks later.

Our GPhC-registered clinicians can provide advice about antibiotics via our online video consultation service. They are available between 9.30am-4.30pm, five days a week, and can also issue fit notes and referrals to specialists for treatment, where suitable.  

Page last reviewed:  18/06/2020
Side effects and warnings

What side effects can antibiotics cause?

As there are many forms of antibiotics, side effects can vary. The most commonly prescribed antibiotic is penicillin, the side effects of which may include:

Common (may affect up to 1 in 10 people): skin rash, nausea and diarrhoea.

Uncommon (may affect up to 1 in 100 people): vomiting.

Very rare (may affect up to 1 in 10,000 people): thrush, kidney problems, seizures, dizziness, hyperactivity, crystals in the urine, which may be seen as cloudy urine, or difficulty or discomfort in passing urine, discoloured or hairy appearing tongue, anaemia and a low number of white blood cells or cells involved with blood clotting.

If you experience any of the following allergic reactions (very rare), you should discontinue use and seek immediate attention: skin itching or rash, swelling of the face, lips tongue, body or breathing difficulties, a rash or pinpoint flat red round spots under the skin surface or bruising of the skin, fever, joint pain, enlargement of lymph nodes, reddish purple patches on the palms of the hands or soles of the feet, hives, fever, blistering, pustules, peeling, redness, pain, itching, scaling, flu-like symptoms, abnormal blood test results, muscle pain, inflammation of the large bowel with diarrhoea with bleeding, darker urine or paler stools or yellowing of the skin or the whites of the eyes.

Taking antibiotics with other medications

Before you start any treatment, you should inform your doctor about other medications you are currently or have recently taken. Different antibiotics may have different contraindications (issues that make treatment unsuitable or problematic), so it should be noted that the following treatments apply to penicillin only: allopurinol, probenecid, warfarin, tetracycline and methotrexate.

Warnings and precautions

Penicillin may not be suitable for you if you have any of the following conditions: kidney problems, glandular fever, lymphatic leukaemia, HIV infections or issues with urinating. If you have any of these conditions, you should alert your doctor to them. 

It should also be noted that some blood tests may be affected by this treatment, so you should inform your doctor before you undergo any tests.

What types of antibiotics are there?

Antibiotics can be found in many forms, from tablets and capsules to oral suspensions and creams. They treat many bacterial infections. Some of the most common include penicillins (amoxycillin), tetracyclines (minocycline), cephalosporins (cefuroxime), quinolones (ciprofloxacin), lincomycins (clindamycin), macrolides (erythromycin), sulphonamides (sulfasalazine), glycopeptides (dalbavancin) and carbapenems (meropenem).

Page last reviewed:  18/06/2020

Is it safe to use antibiotics during pregnancy or while pregnant?

It depends on the antibiotic and the risks associated with the infection. You should inform your prescribing clinician if you are pregnant or breastfeeding.

Will antibiotics affect my ability to drive?

Some people may experience side effects such as dizziness, and you should refrain from driving in these circumstances. You should establish what effects your treatment has on you before operating any heavy machinery.

Can I consume alcohol during treatment?

Alcohol has no impact on some treatments, but may not be suitable with other antibiotics. You should discuss this with your clinician before starting a course of treatment with antibiotics.  

Could I be allergic to antibiotics?

Around one in 15 people in the UK are allergic to antibiotics, most commonly penicillin and cephalosporin. Typically, these amount to little more than a mild rash or coughing, which can be treated with antihistamines. In rare cases however, serious reactions called anaphylaxis can be life threatening. If you have a suspected allergy to any antibiotic, inform your doctor.

Can I buy antibiotics over the counter?

No. Antibiotics are available via prescription only. 

Where can I find out more about antibiotics online?

If you would like to speak to a GMC-registered clinician about antibiotics, our online video consultation service is available from 9.30am-4.30pm, Monday to Friday. Our clinicians can also provide fit notes and referral to specialists for treatment, where suitable. 

Page last reviewed:  18/06/2020

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