Advising on missed or delayed doses of medicines

Samantha Owen, Principal Pharmacist Critical Evaluation and UKMi Medicines Q&A Lead, Southampton Medicines Advice Service, University Hospital of Southampton NHS Foundation TrustPublished Last updated See all updates

Guidance to advise people who occasionally forget or are late in taking a dose of their medicine(s).

Problems with missed doses of medicines

Sometimes people forget to take their medicines at the usual time.

This may cause a problem because missing a dose may make the medicine less effective, but taking doses too close together may increase the risk of side effects.

Here we provide guidance on the steps to follow (see below) to advise patients who occasionally forget or are late taking a dose of their medicine(s). The guidance does not apply to patients who frequently miss doses.

Do not take a double dose

Never take a double dose to make up for a forgotten dose unless specifically advised.

Limitations of our advice

There will be many situations that cannot be covered by general advice such as this, and healthcare professionals should always consider individual circumstances.

If in doubt, people should seek advice from a pharmacist, doctor or their specialist nurse/clinic.

This is particularly advisable if:

  • they have missed more than one day of treatment
  • they are taking the medicine less frequently than once a day (e.g. on alternate days, once weekly, monthly) or they are following a less typical dosing regimen
  • they are taking certain medicines that need special care or have special instructions (see ‘Advice for Specific Medicines’ below)

The guidance does not apply to missed or delayed doses in hospital. Refer to the SPS Tool: Reducing harm from omitted or delayed medicines in adults in hospitals or contact the hospital pharmacy or medicines information department for advice and information on missed doses in this setting.

Advice for specific medicines

There are many medicines that need special care or have special instructions, and it is not possible to include advice for them all.

Below we give advice for some of the more common medicines people may be taking that would fall into this category.

For all these medicines, the advice still applies to:

  • check the Patient Information Leaflet for specific instructions on missed or forgotten doses.
  • seek further advice from a pharmacist, doctor or specialist nurse/clinic if there are any concerns or any doubt as to what to do.

Epilepsy medicines

It is especially important for people with epilepsy to take their anti-epileptic medicines regularly.

Missing a dose could trigger a seizure, although this would be rare.

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.

An Epilepsy Society website article on Strategies and tools for taking medication recommends that:

  • If a medication is usually taken once a day, a forgotten dose should be taken as soon as it is remembered.
  • For medicines taken twice a day, a forgotten dose can be taken if it is within 6 hours after it was due (i.e. less than 6 hours late). If the dose is more than 6 hours late, it should be omitted and the next dose taken at the usual time.

Oral contraceptives

Protection against pregnancy may be affected if people miss doses of their oral contraceptive pill.

The advice varies according to:

  • the type of oral contraceptive, i.e. combined pill or progestogen only pill (mini-pill),
  • how many pills have been missed, and
  • when the pills have been missed

It is safe to follow advice in the Patient Information Leaflet supplied with the pill. But this doesn’t necessarily follow official guidance from experts and can sometimes be overly cautious.

For this reason, people should speak to a pharmacist or call 111 for advice on missed doses of oral contraceptive pills.

Alternatively the following organisations provide reliable advice:

Warfarin

Warfarin should be taken as a single dose at the same time each day.

Advice on missed or forgotten doses in manufacturers’ Patient Information Leaflets (PILs) varies.

Although it is perfectly safe and acceptable to follow the advice in the PIL, people may prefer to follow the pragmatic advice offered in the Warfarin Anticoagulant Record (Yellow Book):

“If you miss a dose and remember before midnight, you can still take that dose. If you forget your dose for a longer time, do not take that dose to catch up, but take your next dose when it is due.”

People should make a note of any missed doses, preferably in their anticoagulant record book, and remember to tell the healthcare staff at their next blood test appointment.

If they are worried, or have missed more than one dose, they should contact the anticoagulant clinic or their doctor for advice.

Never take a double dose of warfarin to make up for a missed dose.

Insulin

People with diabetes (type 1 or type 2) will be at risk of high blood glucose (hyperglycaemia), and possibly diabetic ketoacidosis, if they unintentionally miss insulin doses.

They should follow any specific instructions given by their diabetes nurse/clinic or GP for this scenario.

Never take a double dose of insulin to make up for a forgotten dose.

People should check their blood glucose level, and they may also need to test their urine for ketones, particularly if they have any symptoms.

They should contact their diabetes nurse/clinic or GP if they have any concerns or need advice on subsequent doses.

Methotrexate once-weekly

Doses of once-weekly methotrexate should normally be taken on the same day each week. The NHS National Patient Safety Agency patient information leaflet: Methotrexate treatment gives guidance on what to do if people forget to take their tablets.

If a dose is missed, advice depends on when it is remembered:

  • Within 2 days: take the forgotten dose now, then take the next dose as normal. For instance if a person normally takes their methotrexate on a Tuesday, they could take it on Wednesday or Thursday, then take their next dose on Tuesday as normal.
  • 3 or more days later: contact a doctor or the patient’s specialist nurse/clinic for advice.

Never take a double dose of methotrexate to make up for a missed dose.

It is unlikely that a disease flare-up would occur as a result of a single missed dose.

Parkinson’s disease medicines

Taking medicines for Parkinson’s disease on time is extremely important for managing Parkinson’s symptoms.

A missed or late dose could mean the patient is unable to move, get out of bed, swallow, walk or talk.

Even a delay of 30 minutes could be serious, with a risk of Neuroleptic Malignant Syndrome (NMS) when medicines for Parkinson’s disease are suddenly stopped.  This is a rare, but serious and potentially fatal reaction. Symptoms include stiffness, muscle twitching, shaking, agitation, confusion, high body temperature (hyperpyrexia), increased heart rate, unstable blood pressure and coma.

Further information and advice about taking medicines for Parkinson’s disease on time is available from:

A Parkinson’s UK Q&A: The Importance of getting Parkinson’s Medication on Time gives the following advice for people if they forget to take a dose of their medicine(s):

  • “If you forget to take your dose, take it as soon as you remember and then adjust the time of your next dose. For example, if you normally take doses at 8am, 12pm, 4pm and 8pm and you forget your midday dose until 2pm, take it then and adjust your next doses to 6pm and 10pm.

  • Do not take two doses together to make up for a dose that you forgot to take or take your late dose really close to your next one. This is because you might experience side effects including nausea or dizziness.

  • If you are taking a once daily medication and you forget a dose, you can still take the dose if you remember on the same day. But, if you don’t remember until the following day you shouldn’t double up your dose.

  • If you forget your medication you may experience increased Parkinson’s symptoms. It can happen on the same day or the day after, so make sure you are careful about driving your car or using machinery.”

People should contact their Parkinson’s nurse/clinic, pharmacist or GP if they have any concerns about a missed or late dose, or need advice on subsequent doses.

Advice and tips on managing medicines for Parkinson’s disease are available for patients and carers on the Parkinson’s UK website: Managing drug treatments for Parkinson’s.

Bisphosphonates for osteoporosis

Bisphosphonate medicines for treating or preventing osteoporosis (alendronic acid, risedronate, ibandronic acid) have very specific instructions on how and when to take them.

They must be taken on an empty stomach, sitting or standing upright, with a full glass of plain water. This is to make sure they work properly and to reduce possible irritation of the oesophagus.

For this reason, the advice is usually to take them shortly after getting up for the day, 30 to 60 minutes before the first food, drink (other than plain water) or other medicines of the day.

Doses of bisphosphonate medicines vary. Alendronic acid and risedronate may be taken once daily or once weekly, while ibandronic acid is taken monthly. For once weekly or monthly dosing, people are advised to stick to a schedule, i.e. same day each week or a certain day each month.

If they miss or forget a dose, it is important for people to follow the advice in the PIL specific to the bisphosphonate they are taking.

Royal Osteoporosis Society advice on getting the best from your osteoporosis medication reassures people that missing the odd dose is unlikely to affect overall bone health.

The following advice may be offered if a PIL is not available:

Once daily alendronic acid: If you forget to take your dose at your usual time, skip that dose. Take the next dose as usual the next day. Do not take two doses on the same day.

Once daily risedronate: If you forget to take your dose at your usual time, you can either:

  • skip that dose, then take the next dose as usual the next day, or:
  • take the missed dose at the next possible time, making sure you take it on an empty stomach. This could be between meals or in the evening, as long as it is at least 2 hours after your last food, drink (other than plain water) or other medicines. You should wait for 2 hours after taking the dose before eating or drinking (other than plain water).

Do not lie down for 30 minutes after taking a dose. Do not take two doses on the same day.

Once weekly alendronic acid or risedronate: If you forget to take your dose at your usual time, do not take it later that day. Instead, take the missed dose the morning after you remember. Do not take two doses on the same day. Then go back to taking your dose once as week as usual on your chosen day.

Monthly ibandronic acid: If you forget to take your dose on your chosen day, check when your next scheduled dose is due:

  • if it is more than 7 days away, take the missed dose the morning after you remember. Do not take a dose later in the day.
  • if it is 7 days or less away, skip the missed dose, and take the next dose as scheduled. Do not take two doses within the same week.

Then continue taking one tablet once a month on the scheduled days as planned.

Immunosuppressant (transplant rejection) therapy and cancer medicines

People should ask their doctor or specialist nurse/clinic for advice on what to do if they have missed a dose of transplant rejection or cancer medicine.

Other useful SPS content

Change history

  1. Amended term 'blood sugar' to 'blood glucose' following user feedback
  1. Amended title to improve searchability of the article, and minor edits to include links to SPS tool for omitted or delayed doses in hospitals.
  1. Published