Taking medicines

This information explains what medicines do, possible side effects, how to take medicines safely and where to find further advice.

What do medicines do?

The medicine you are taking may:

  • Treat your condition, for example an antibiotic to treat certain infections.
  • Control your condition, for example a medicine to lower your blood pressure.
  • Treat the symptoms of your condition, for example a painkiller for toothache.
  • Prevent you from becoming unwell, for example a vaccination against disease.

Will my medicine cause side effects?

Most people take medicines without suffering any unwanted side effects, but all medicines can cause side effects which may vary from person to person.

The medication information leaflet supplied with your medicine will list all the known side effects that the medicine may cause.

What is meant by a “common” or “rare” side effect?

The chance, or risk, of having a side effect may be described using words or figures, or both. This is how risk may be described in your medication information leaflet:

  • Very common means that more than 1 in 10 people taking the medicine are likely to have the side effect.
  • Common means that between 1 in 10 and 1 in 100 people are affected.
  • Uncommon means that between 1 in 100 and 1 in 1,000 people are affected.
  • Rare means that between 1 in 1,000 and 1 in 10,000 people are affected.
  • Very rare means that fewer than 1 in 10,000 people are affected.

Important: if a side effect has a risk of 1 in 10,000, then 9,999 out of every 10,000 people taking the medicine are not expected to experience that side effect.

How much medicine should I take?

To get the most benefit from your medicine, you need to take the dose recommended for you and for the length of time advised.

For medicines that have been prescribed for you, the dose instruction will be on the pharmacy label on the medication. This dose takes into account your age, weight, other clinical factors and any other medicines you may be taking. Only change this dose if you have discussed it with the clinician who prescribed it.

With some medicines, you may start on a low dose and gradually increase the dose. For other medicines, you may stay on the same fixed dose throughout your course of treatment.

Sometimes, when you need to stop taking a medicine, your doctor will gradually reduce the dose to avoid unpleasant withdrawal effects.

Important: check the medication information leaflet and speak to your doctor or pharmacist if you feel unwell after your dose has changed.

How can I reduce the risk of side effects?

Be careful about mixing medicines. Some medicines should not be taken together.

Before taking a new medicine, it is important to tell the pharmacist or clinician who prescribed it about any other medicines you are already taking. Do not forget to tell them about herbal remedies or any non-prescription medicines you may have bought in a pharmacy, supermarket or online.

Be aware that some things can increase the chance of your medicine causing side effects. Your medication information leaflet will tell you about any known risk factors and what you can do to help reduce the chance of side effects.

For example, you may be able to lower the risk of side effects by not drinking alcohol or not eating certain foods during your course of treatment.

Do side effects always come on straight away?

It depends on the medicine and the person.

Some side effects can happen immediately, for example an allergic reaction.

Some side effects might not start for several days or weeks, for example skin rashes, or may take even longer to appear, for example stomach problems with some painkillers.

In general, side effects are most likely to happen soon after you start a new medicine or after your dose has changed.

Quite often, mild side effects will go away as your body adjusts to the new medicine or dose.

Medicines of animal origin which may be a concern

If you are concerned about medication products of animal origin, for example from pig or gelatine, please speak to your doctor or pharmacist.

Taking medicines: where to find further advice

  • Check your medication information leaflet for information on side effects and action to take.
  • If in doubt, speak to your doctor, nurse, midwife or pharmacist, or call NHS 111 out of hours.
  • You or your healthcare provider can report suspected side effects in confidence to the drug safety regulatory agency, the Medicines and Healthcare products Regulatory Agency (MHRA), using the Yellow Card scheme.

It is easy to report suspected side effects:

Pharmacy Medicines Information Patient Helpline

If you need further advice about your medicines, you can also contact the Pharmacy Medicines Information Patient Helpline, Monday to Friday, 9am to 5pm.

Out of hours, please contact NHS 111.

Patient Advice and Liaison Service (PALS)

If you have concerns, comments or feedback about your care, treatment or experience at our hospitals, our Patient Advice and Liaison Service (PALS) can help.

For information about how to contact PALS or share feedback with the Trust, please visit our Patient Advice and Liaison Service (PALS) page.