Side effects: what everyone needs to know

We're living longer than ever, and on the whole we're living well. But treating and preventing the big killers of the past (heart attack, stroke, heart failure, diabetes) usually means taking tablets, and all tablets can have side effects.

If a new symptom listed as a side effect starts within hours or days of taking a new medicine, the medicine is likely to be to blame. If you get the same symptom after taking a medicine without problems for months, it's much more likely to be down to an unrelated cause.

There are a few exceptions - for instance, a group of drugs called the ACE inhibitors, widely used to treat high blood pressure, can cause a dry cough which may start many months after you go on to treatment. This isn't dangerous but can be extremely disruptive to your life. A potentially more serious side effect of ACE inhibitors is a condition called angio-oedema which can also develop long after you start treatment. Anti-inflammatory tablets are very widely taken for pain and inflammation. Many people have no side effects in the short term, but in people taking higher doses for long periods, they're more likely to cause side effects such as indigestion or bleeding from the stomach. They may also increase your risk of heart attack and stroke if you take them long term.

Remember that many side effects are temporary, wearing off within a few weeks if you stick with treatment. Others may be connected to how you take your medicine - for instance, anti-inflammatory drugs and some antibiotics like erythromycin are far more likely to cause sickness and tummy pain if you take them on an empty stomach. Likewise, the side effects of 'not' taking the tablets (eg damage from raised blood sugar if you're taking tablets for type 2 diabetes, heart attack if you don't take statin tablets when you've been advised to) may be more serious than the short-term side effects of the medication.

Once allergic, always allergic

If you're told you're allergic to one kind of penicillin, you must never take any kind of penicillin again, as the reaction might be much worse next time. About one in 10 people allergic to penicillin are also allergic to another family of antibiotics called the cephalosporins. Make sure your dentist, as well as your doctor, knows.

Your friendly pharmacist

Your doctor and pharmacist should check before you get your medicine if there's any reason you definitely shouldn't take a given medicine. But if you do get side effects, make your pharmacist your first port of call for advice.

How common is common?

If you were to read every side effect on the patient information leaflet that comes with prescription medicines, you'd probably throw them all in the bin immediately! Remember that side effects are divided into:

- Very common (more than one in 10 people taking the medicine are likely to get that side effect)

- Common (between one in 10 and one in 100)

- Uncommon (one in 100 to one in 1,000)

- Rare (one in 1,000 to one in 10,000)

- Very rare (under one in 10,000)

A 'common' side effect still means up to 99% of people won't be affected, and just because 'cough' is listed as a possible side effect doesn't automatically mean your tablet is to blame.

Cutting the risks of side effects

- Always check with your pharmacist when you first get a medicine to see if there are special instructions on how to take it

- Tell your doctor or pharmacist about all the medicines you take, including non-prescription drugs and herbal remedies, so they'll know if a new tablet might interact with them

- Always stick to the prescribed dosage

- Check with your pharmacist if any other factors, like drinking alcohol or eating certain foods, could increase the risk of side effects.

With thanks to 'My Weekly' magazine where this article was originally published.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.