Anastasia Aluvilu
Frieda Shigwedha
Statistics show that more than 80% of people occasionally miss a dose of their medication. While this is unintentional, the effects of missing a dose may be clinically important. In most cases, individuals end up doubling doses to make up for the missed dose(s), not taking at all, or taking other wrong actions with even more detrimental effects.
This article will educate readers on the effects of missing doses, provide sources to consult for more information when a dose is missed and how to minimise forgetfulness.
Treatment with antimicrobials such as antifungals, antibiotics and antiparasitics usually follow a diagnosis of an infection, to treat the causative microorganisms. Antimicrobials require that a certain concentration of an antimicrobial is reached first before they can work, to inhibit or kill the microorganism. Missing a dose will reduce the chances of reaching this concentration and consequently make the treatment ineffective.
In addition, missing doses or not taking as recommended allows the microorganisms to adapt leading to antimicrobial resistance, making treatments less effective in the future for the individual and the larger population.
This also applies to antiretroviral (ARV) medicines.
Blood levels of medicines like anti-seizures (phenytoin) and psychotropics (lithium), blood thinners (warfarin), and heart failure or heart rhythm regulating medicines (digoxin) need to be within a certain range known as the therapeutic window. Levels below the lower limit will make the medicines ineffective, which can be serious and life threatening.
Missing doses of these medicines have serious consequences, some of which are evident right away, and others after a few doses have been missed. This includes relapsing or worsening of the seizure episodes, increased risks of blood clots leading to strokes or worsening of heart failure or heart dysrhythmias. Taking medicines as advised by the healthcare providers will ensure that the medicine levels will remain within the safe window to treat the medical conditions.
Missed doses of oral contraceptives have been well studied
Women taking oral contraceptives should be aware of the possibility of becoming pregnant if they have missed taking the pill. There is an increased risk of becoming pregnant if pills are missed during the first week or at the end of the current pack. Also, the type of the pill missed, whether the inactive or active pill matters and will be treated differently, and sometimes the use of additional contraception may be necessary.
Insulins are a common component of the therapy for diabetes mellitus (DM) type one and in some cases of DM type two and require taking it at the same time every day to keep the glucose levels controlled. The short-acting and rapid-acting insulins (Insulin glulisine, Insulin aspart, Insulin lispro, Insulin regular) are usually taken before meals, while intermediate-acting insulins (Isophane NPH) and long-acting insulins (Insulin glargine, Insulin detemir, Insulin degludec) are for controlling glucose levels over long periods. Missing an insulin dose can lead to a rapid rise in dangerous glucose levels (hyperglycaemia) and may lead to a life-threatening complication called diabetes ketoacidosis, leading to diabetic coma and then death.
Treatment of asthma and allergic conditions usually includes medicines for immediate relief of acute attacks and medicines to keep the symptoms under control and prevent future episodes. Missing doses of your preventive asthmatic or allergy treatment will increase your chances of experiencing these attacks and the frequency of their occurrence.
Usually, each medicine is accompanied by a patient information leaflet, providing information on that medicine including guidance on missed doses. Therefore, always refer to the product information or your healthcare provider for more information in these cases. Information generally includes statements such as:
If you forget to take one or more doses, take your next dose at the normal time and in the normal amount. Do not double the dose.
If you miss one dose, skip it, and continue with your normal schedule.
Take as soon as possible, making sure that there are at least several hours between the dose you are taking and your regular dosing schedule. However, if it is time for the next dose, skip the missed dose and go back to the regular dosing schedule.
The benefits of maintaining a stable and efficient medication schedule outweigh the consequences and steps to be taken following the missed doses. Therefore, patients should explore effective methods to prevent forgetting such as:
Taking the medications at the same time every day to develop a routine
Using pill containers, breaking down doses by day and time, usually available to buy in pharmacies
Using a medicine calendar, setting reminders and daily alarms on mobile phones
Involving and asking to be reminded by a partner, caretaker, relative or housemate
If everything else fails, patients should consult their healthcare providers for guidance to establish other effective ways
Anastasia Aluvilu and Frieda Shigwedha are medicines information and safety pharmacists at the Therapeutics Information and Pharmacovigilance Centre, Namibia Medicines Regulatory Council.