Understanding Antibiotics

With GP surgeries buckling under increasing workloads, the public is encouraged to make better use of their local pharmacies. Pharmacists are trained and qualified to offer advice and dispense certain medications without a prescription. But one item they are not allowed to dispense off-prescription is antibiotics. Why is this? Are antibiotics so dangerous they can only be taken under medical supervision and if so, why?

What are antibiotics?

Antibiotics are medicines that are commonly used to treat or prevent the escalation of bacterial or parasitical infections. They are useless against things like colds and flu, which are caused by viruses. They are usually taken orally in tablet form, but in severe infections they are given intravenously. They can also be given as creams or ointments to treat skin infections. 
The most familiar form of antibiotic is penicillin, which commonly goes under the name of flucloxacillin or amoxicillin. However, there are several different types and each type is designed to tackle specific bacteria. Antibiotics work by killing the bacteria or the parasite that causes the infection.

What are the side effects of antibiotics?

So what exactly is it about antibiotics that make them so dangerous and they can only be prescribed by doctors? Firstly, you need to look at why they are given. Antibiotics treat a wide range of illnesses and infections, some of which can only be accurately diagnosed by a doctor. The doctor will have access to relevant information, such as the function of a patient’s liver and kidneys, severity of the infection and the patient’s medical history. He or she can then choose the appropriate treatment. It is the powerful effects and side-effects that are the key reason why antibiotics should be carefully prescribed.

The side-effects of antibiotics can vary according to the type, but the most common side-effects include nausea and either diarrhoea or constipation. Less common effects can include allergic reactions of varying severity. They can sometimes destroy good bacteria in the body, leading to secondary infections like thrush. 

For many years, doctors would avoid prescribing antibiotics to pregnant women believing that they could cause foetal defects. However, recent Canadian research has shown that macrolides (a range of antibiotics used instead of allergy-inducing penicillin) are no longer considered to be detrimental to pregnant women. A study by the Quebec Pregnancy Cohort involving 135,839 pregnancies concluded that the risk of major foetal malformations is more likely to come from other medical issues rather than the antibiotics used to treat them.  

What affects antibiotics?

A patient who is prescribed antibiotics will be told whether to take them with food or on an empty stomach. Certain foods can affect how medicines work, either by interfering with the digestion and absorption of medicines or by blocking how the medicine is broken down and processed by the liver, kidneys or intestines. For example, milk can block antibiotic (in particular tetracyclines) absorption in the stomach; some fats and fibres can slow down digestion, thereby slowing the rate of absorption of the medicine. It is said that highly acidic foods like grapefruit can interfere with antibiotic absorption. It’s important to remember that the various types of antibiotics may be subject to differing degrees of interference although most common antibiotics should be taken with food. 

The NHS advises that in most cases, a patient need not to refrain from drinking alcohol when taking antibiotics but this should be in moderation only. However, there are some cases when alcohol should be avoided completely and these are the treatments that include:

• Metronidazole
• Tinidazole
• Co-trimoxazole
• Linezolid
• Doxycycline
• Erythromycin

Symptoms of side effects can include breathlessness, headaches, nausea, chest pain and lightheadedness. Antibiotics can also react with other drugs such as the contraceptive pill, antifungals and diuretics.

Why self-medication is dangerous

We have often heard of this term, where patients diagnose their illness and decide for themselves what medicine they need. Whilst the intention may be good, it is never a good idea because of a) the danger of getting it wrong and b) the danger of taking the wrong medication. Most doctors are familiar with patients who are convinced that antibiotics are the answer to their problems, but, unfortunately, overuse of these powerful medicines has led to the phenomenon of antibiotic resistance and the rise of ‘superbugs’ like c.diff and MRSA.

It is vital that we do not squander the advances made in the field of antibiotics by over-using them, so if you have any concern about a certain treatment that includes antibiotics, please don't hesitate to get in touch.