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When can medicine problems occur?

While problems with medicines can happen at any time, there are some situations when they are more likely to happen. Medicine mistakes are particularly common if you are going into or leaving hospital. Around half of medication errors in hospitals occur when you are admitted or discharged home. Changes in your health and your medicines can also result in more side effects, interactions and medicine mistakes. Lack of communication with — and between — the people involved in your health care often contributes to medicine problems happening. You may find it helpful to have a carer or family/whānau member with you when talking to anyone involved in your health care.


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When your medicines change

Let your doctor, pharmacist and other health professionals know about:

  • any problems you experience or concerns that you have after starting a new medicine
  • any changes that are made during your treatment (e.g. changes in the dose you take).

All medicines — prescription and non-prescription — can cause side effects, interactions and other medicine problems. Non-prescription medicines include over-the-counter medicines from a pharmacy or supermarket, and complementary medicines such as herbal remedies, vitamins and minerals.

Starting a new medicine

Side effects and medicine interactions are often more likely — and can be more severe — when you first take a new medicine. This can be because your body isn't yet used to the effects of the medicine.

Side effects that can be more problematic when you start taking a medicine include:

  • dizziness or light-headedness
  • drowsiness or reduced alertness
  • feeling agitated or restless
  • nausea or vomiting.

Starting another medicine may also mean that you begin to have trouble managing all of your medicines, especially if you are already taking several different medicines.

Changes in the dose of your medicines

Side effects and medicine interactions may depend on the dose of the medicines you are taking. Generally, the more of a medicine you take, the more likely you are to experience these problems.

You may begin to experience side effects and interactions when your medicine dose increases. With some medicines, decreasing the dose could also affect another medicine you take.

Dose adjustments can mean changes to when and how much of your medicines you take, which may make it harder for you to manage your medicines, or easier to confuse and mix them up.

Having to take a medicine for a long time can cause problems too. For example, dependence on sleeping pills such as temazepam is more likely when you take them for longer than 2 weeks.

When your health changes

If you develop a new medical condition or a new symptom, you may be prescribed another medicine. This can increase your chance of side effects and medicine interactions.

Medicines you currently take for one medical condition may affect a newly diagnosed condition. For example, heart failure can be worsened by a non-steroidal anti-inflammatory medicine taken to relieve pain or inflammation.

Problems can also arise if you take a medicine left over from a previous illness or a medicine that is not prescribed or recommended for you. What's right for another person or medical condition may not be right for you. Do not share medicines with other people, even if they have the same health problem.

Some medical conditions or symptoms can also interfere with how well you manage your medicines. Common causes of medicine problems include:

  • confusion or memory loss
  • poor eyesight or hearing
  • difficulty swallowing
  • reduced physical ability due to muscle or joint problems.

When your health care services change

Multiple health problems when you are older can mean that you will need to see more than one doctor or other health professional, and sometimes you may need to be cared for in hospital.

Going into and leaving hospital

New medicines are often started in hospital, and medicines you have been taking for a long time may be changed or stopped. This can increase your chance of medicine problems for various reasons. For example, you may:

  • end up taking more medicines after you leave hospital
  • be prescribed medicines that can cause serious problems
  • have to take your usual medicines differently, or in a more complicated way
  • be given a different brand of medicine from the one you usually take.

Lack of communication and medicine mistakes in hospital

  • Hospital staff may not have correct or complete information about all the medicines you are currently taking.
  • You and your usual doctor may not be fully informed about changes to your medicines after you leave hospital, including new and stopped medicines.
  • Your doctor may not immediately receive the information they need about your hospital treatment.

Keeping an up-to-date medicines list is a good way to keep track of all the medicines you are taking.

Seeing many health professionals

It is important that you tell all the people involved in your health care about all the medicines you are taking. This will help to make sure that they have all the information they need when prescribing or recommending medicines for you.

For example, your GP needs to know about medicines prescribed by your specialist before they prescribe another medicine for you. This is important to help you avoid medicine problems such as side effects and interactions.

What else can I do?

  • Use a medicines list to help keep track of your medicines: record any changes that are made to your medicines, and show the list to all the people involved in your health care.
  • Talk to your health professional about your health, your wellbeing, and your medicines. Ask if any new symptoms you are experiencing could be due to any medicines you are taking.
  • Ask your doctor or pharmacist about having your medicines reviewed if you have recently spent time in hospital.
  • Find out about other ways that you and your carers can help to prevent medicine problems.

It’s OK to ask questions
If you have questions about your symptoms or the medicines managing your symptoms, speak with your health professional.

You can also download this information as a pdf (398 KB).

Adapted from NPS MedicineWise (2013), When can medicine problems occur? Reasonable care is taken to provide accurate information at the time of creation. This information is not intended as a substitute for medical advice and should not be exclusively relied on to manage or diagnose a medical condition. NPS MedicineWise and Choosing Wisely New Zealand do not assume any responsibility or liability arising from any error or omission or from reliance on any information in this resource.