Medicines Q&As
Q&A 338.2
What should people do if they miss a dose of their medicine?
Prepared by UK Medicines Information (UKMi) pharmacists for NHS healthcare professionals
Before using this Q&A, read the disclaimer at www.ukmi.nhs.uk/activities/medicinesQAs/default.asp
Date prepared: 19th November 2013
Background
Sometimes people forget to take their medication at the normal time. This causes a problem because
missing a dose may make the medicine less effective, but taking subsequent doses too close together
increases the risk of side effects.
It is very difficult to give general guidance on what to do in these situations. Each situation needs to
be looked at individually. However, this Medicines Q&A offers some general guidance, which may
help people who occasionally forget or delay a dose. This guidance does not apply to patients
who forget doses frequently.
Answer
Always look first in the manufacturer’s Patient Information Leaflet (PIL) supplied with the medicine.
Many of these can be viewed at the electronic Medicines Compendium (eMC). Type the name of the
medicine into the search box and if there is a PIL, it will be listed. PILs usually contain specific advice
about missed doses. Note that not all medicines are included, and that the Summaries of Product
Characteristics (SPCs) on the same website generally do not have missed dose information. Only use
the rest of this document if you cannot find a PIL.
There will be many situations that cannot be covered by a document like this and if in doubt contact
the GP or a pharmacist for advice. This is particularly advisable if more than one day of treatment has
been missed.
General Advice
There is no situation where the next dose should be doubled if one is missed. This could be harmful.
As a general rule for all oral medicines it is usually acceptable to take a dose up to 2 hours
late. In these circumstances any warnings about taking before or after meals can usually be
ignored, as it is more important to take the dose.
If people take medicines at shorter intervals than usual, they may get more side effects.
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If the dose is more than 2 hours late for medicines taken once or twice each day people
should usually take the dose as soon as they remember as long as the next dose is not due
within a few hours. People should then continue as normal. The definition of a “few hours” will
vary with each situation. Seek further advice if you’re not sure what this means for you.

If the dose is more than 2 hours late for medicines taken frequently throughout the day
it is usually advised to omit the missed dose, wait until the next dose is due, then continue as
normal. For example, this advice would apply to an antibiotic or painkiller taken four times per
day.
Available through NICE Evidence Search at www.evidence.nhs.uk
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Medicines Q&As
Specific Medicines
 Epilepsy medicines: it is especially important for patients with epilepsy to take their antiepileptic medicines regularly. Missing a dose could trigger a seizure. Usually people should
take their dose as soon as they remember unless the next dose is due within a few hours.
People who miss doses should avoid activities where having a seizure could be dangerous.
Specific advice from the Epilepsy Society about children (aged 12 and under) with epilepsy
states that if medication is usually taken once a day, a forgotten dose should be given as
soon as it is remembered. For twice a day medication, a forgotten dose can be given if it is
within six hours of being due, otherwise it should be omitted and the next dose given at the
usual time (1).

Oral contraceptives: look in the manufacturer’s Patient Information Leaflet (PIL) supplied
with the medicine or contact a pharmacist for advice.

Warfarin: warfarin should be taken at the same time each day (2).
If patients usually take warfarin in the evening and remember before midnight on the
same day that they have missed a dose, they can take the dose. After midnight, the dose
should not be taken. Subsequent doses should be taken at the usual time (2).
If patients normally take warfarin in the morning and have forgotten a dose, the
general advice is (2):
 if the dose is less than two hours late, they should take the dose as soon as they
remember and then continue as normal.
 if the dose is more than two hours late, they can take the dose as soon as they
remember, but if it is time to take the next dose, they should omit the missed dose.
Never take a double dose (2).
If a dose is not taken, make a note in the warfarin booklet and remember to tell the doctor at
the next blood test appointment. If you are worried contact the anticoagulant clinic or the
doctor for advice on any increased monitoring requirements.

Insulin: follow the advice given by the GP or diabetic clinic.

Methotrexate once-weekly: if a dose is missed, it can be taken as soon as it is remembered
if this is within two days. However, if the dose has been missed for more than two days then a
doctor should be contacted for advice. A double dose should not be taken to make up for a
missed dose (3).

Immune therapy and cancer medicines: ask the doctor for advice on what to do if a dose of
transplant rejection or cancer medicine is missed.
People who frequently forget doses should speak to a pharmacist. The pharmacist can advise how to
change medication to a simpler regimen, give tips on ways to help remember, or recommend a
compliance aid. These aids are boxes which allow medicines to be put into labelled compartments to
remind people to take them at specific times of the day or days of the week. There are many different
types, some of which are pocket-sized, but note that not all medicines are suitable for these devices.
Available through NICE Evidence Search at www.evidence.nhs.uk
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Medicines Q&As
Summary
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Patient Information Leaflets (PILs) usually have advice on missed doses.
If people take medicines at shorter intervals than usual, they may get more side effects. Never
double the next dose if one is missed.
For any oral medicine it is usually all right to take a dose up to 2 hours late.
If the dose is more than 2 hours late, and for medicines taken once or twice each day people
should usually take the dose as soon as they remember as long as the next dose is not due within
a few hours. For medicines taken more frequently, the missed dose should be omitted.
For missed doses of warfarin, insulin, oral contraceptives, epilepsy medicines, once-weekly
methotrexate, cancer medicines or immunosuppressants see above.
If more than one day of treatment has been missed then contact the GP or a pharmacist for
advice.
People should speak to their pharmacist if they regularly forget doses.
Limitations
This is not intended as definitive guidance, but general advice based on the opinions of the authors
and their advisers. It may not be applicable in all circumstances. Seek appropriate advice if uncertain.
It is very difficult to give general guidance on what to do in these situations. Each situation needs to
be looked at individually. This Medicines Q&A does not cover the situation where a patient vomits
their medication.
References
1. Epilepsy Society. Medication for children. Accessed on 19th November 2013 via
http://www.epilepsysociety.org.uk/anti-epileptic-drugs-children
2. Patient Information Leaflet. Marevan® 1mg, 3mg & 5mg tablets. Amdipharm Mercury
Company Limited. Accessed on 19th November 2013 via http://www.medicines.org.uk/emc/
3. Patient Information Leaflet. Maxtrex® tablets 2.5mg. Pharmacia Ltd. Accessed on 19th
November 2013 via http://www.medicines.org.uk/emc/
Quality Assurance
Prepared by
Sue Gough, Critical Evaluation Pharmacist (based on earlier work by Simon Wills and Katie Taylor),
Wessex Drug and Medicines Information Centre, University Hospital Southampton NHS Foundation
Trust
Date Prepared
19th November 2013
Checked by
Kate Pickett, Medicines Q&A Pharmacist, Wessex Drug and Medicines Information Centre, University
Hospital Southampton NHS Foundation Trust
Date of check
26th November 2013
Search strategy
 In-house clinical experts.
 Consensus view of a national medicines information team.
 Electronic medicines compendium. Accessed via http://www.medicines.org.uk/emc/
Available through NICE Evidence Search at www.evidence.nhs.uk
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