Taking antiseizure medicines regularly is especially important for people with epilepsy. Missing a dose could trigger a seizure, although this would be unlikely.

Advice

The Epilepsy Society recommends that for once-daily medicines, 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. If the dose is more than 6 hours late, it should be omitted and the next dose taken at the usual time.

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

People who miss doses should avoid activities where having a seizure could be dangerous, for example driving or watersports.

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

While the PIL’s advice on missed doses is safe, it may not align with official expert guidance and can be overly cautious.

Advice

This varies according to the type of oral contraceptive, how many pills have been missed, and when the pills have been missed.

Patient.Info provides advice on missed doses of combined oral contraceptives (COCs) and the progestogen-only pill (POP). They also recommend if additional barrier contraception and emergency contraception are required. The advice is based on COC and POP guidance from the Faculty of Sexual and Reproductive Healthcare Clinical Effectiveness Unit.

PILs providing advice on missed COCs and POPs doses are available from the Family Planning Association.

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

Risks of missed doses

Missed or delayed doses may worsen Parkinson’s symptoms. It could mean the patient is unable to move, get out of bed, swallow, walk or talk.

This could happen on the same day as the missed dose, or the day after, so they will need to be careful, especially when driving or using machinery.

Even a delay of 30 minutes could be serious, with a risk of Neuroleptic Malignant Syndrome when medicines for Parkinson’s disease are suddenly stopped.

Advice

Parkinson’s UK provides practical advice to follow when people forget to take a dose of their medicine(s).

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

If taking a once daily medication, take the forgotten dose if you remember on the same day. If you don’t remember until the next day, skip the forgotten dose.

Never take two doses together to make up for a forgotten dose or take your late dose close to your next one.

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

People with diabetes mellitus will be at risk of high blood glucose (hyperglycaemia), and possibly diabetic ketoacidosis and hyperosmolar hyperglycaemic state, if they miss insulin doses.

Advice

People should follow instructions given by the usual team who manages their diabetes. 

The Right Decision Service from Health Improvement Scotland provides advice for when a dose of insulin is missed. This varies according to the type of insulin and how late the dose is. It includes information on any extra monitoring of glucose or ketones that may be required. This advice may be followed if their usual diabetes team are not available in a timely manner for advice.

Healthcare professionals should advise people to:

• look out for any signs of hypoglycaemia or hyperglycaemia, and check their glucose levels more regularly than usual over the next 24 hours
• contact the usual team who manages their diabetes if they have any concerns or need advice on subsequent doses
• never take a double dose of insulin to make up for a missed dose

Doses of once-weekly methotrexate should be taken on the same day each week.

Advice

The NHS Methotrexate medicines page gives advice on what to do if people forget to take their dose.

Take the dose if it is remembered on the next day or the day after. For example, if a person normally takes their methotrexate on a Tuesday, they can take it on the Wednesday or Thursday. The next dose can be taken as usual, on the following Tuesday.

If the dose is 3 or more days late, skip the forgotten dose entirely, and take the next dose as scheduled on the usual day.

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

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

Advice

Advice on missed or forgotten doses in manufacturers’ PILs varies.

It is safe and acceptable to follow the advice in the PIL. People may however prefer to follow the 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 and it’s after midnight, do not take that dose to catch up, take your next dose when it is due
• never take a double dose of warfarin to make up for a missed dose

Reporting missed doses

People should make a note of any missed doses in their anticoagulant record book and 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 for advice.

People should ask their specialist doctor, nurse or clinic for advice if they have missed a dose of transplant rejection or cancer medicine.