Taking Prescription Medicines Safely

December 12, 2023 by Doctor Vernon Coleman

The following essay is taken from `The Medicine Men’ (first published in 1975):

Many patients have an extraordinary disregard for the dangers they are courting by taking tablets willy nilly. If given once- or twice-a-day therapy, many patients feel that they are not being properly treated and they may simply take more tablets three or four times a day. Some patients even use the simple expedient of finishing up half empty bottles first – regardless of the contents.

The fact is simply that patients tend to take their tablets very much as they please regardless of the instructions they have been given. In many cases when treatment has failed, it can be shown that the patient himself has decided when and how to take his tablets. Some who have got better stop taking drugs which they should continue taking until the course is finished; others stop taking tablets because they have not got better within a couple of days.

In one study of patients given seven-day courses of oral penicillin for acute streptococcal infections, nearly 50 per cent of patients failed to take their medicine as instructed. In another survey conducted on children given antibiotics to take for ten days, 71 per cent had stopped after six days. Parents were seemingly careless of the fact that a complete course of an antibiotic is essential if any good is to be done.

It is not only patients who take short courses of tablets who fail to take medicine as prescribed. It is common for patients to forget to take digoxin and drugs for hypertension, and in fact four entirely independent surveys have shown that patients with TB (who should theoretically be highly motivated and conditioned) do not take their tablets as prescribed (one survey has shown a 50 per cent failure rate). Similarly, diabetics often fail to do what they are told: some 54 per cent failed to take injections as they should do, according to one reliable study. Women attending antenatal clinics had a failure rate of between 33 per cent and 40 per cent when given iron tablets to take. Patients with rheumatoid arthritis are recorded as having a 50 per cent failure rate, and patients with schizophrenia are said to have a 46 per cent failure rate. And, of course, many women taking the contraceptive pill forget or omit to take all their pills, with the result that they become pregnant and then blame the efficiency of the pill.

As a writer in the Journal of the Royal College of General Practitioners put it in 1968: '... Many medical practitioners suspect that the drugs which they prescribe are often taken in doses and at intervals which are decided arbitrarily by the patients, rather than in accordance with the doctors instructions.' He went on to say that 'In many cases where treatment appears to have failed the fault lies in the mode of administration rather than the drug itself.'

A recent survey published in the British Medical Journal showed that 60 per cent of patients in general practice had stopped taking their drugs by the end of the third week and 70 per cent had stopped taking their drugs by the end of the fourth week. Of the rest, only half were taking their drugs properly. Some of these stopped taking tablets because their supply ran out and though they had been told to return to the surgery they did not bother to do so.

In a survey the results of which were published in the American Journal of Hospital Pharmacy in 1966, a nursing instructor studied the medication errors made by patients at home. Of the forty patients in the study thirty-six had made some kind of medication error. The commonest error was one of timing: in other words the patient did not know when to take the tablets which had been prescribed. From this and other research it appears that it is not enough to say to a patient 'Take these tablets four times a day': the doctor should say 'Take these tablets at 8 am, 12 noon, 4 pm and 8 pm.' Some patients were taking medicines that had been stopped: some had several bottles with the same drugs. Some patients made mistakes because they just did not know what their drugs were for. So, for example, a woman who was taking too much digoxin turned out to be taking extra tablets because she thought the digoxin had been prescribed to relieve her asthma. (However, it appeared from the survey that if patients were taught what medicines they were taking and why it did not make much difference to the number of mistakes made.)

The results of the latest survey to deal with this problem were published in the Journal of the American Medical Association in February 1974. A number of patients were interviewed and asked how they would take tablets when given certain instructions. For example, patients were asked what they would do if told to take their tablets every six hours. Only about a third said that they would take their tablets every six hours. A quarter, for example, said that they would not take a dose during the night-time hours. Patients told to take tablets with meals did not seem to know whether to take their tablets with meals, before meals or after meals. Since some drugs are not absorbed properly unless taken when there is no food in the stomach while other drugs cause stomach irritation unless taken when there is food in the stomach, it is easy to see that the effectiveness of prescribed drugs depends very much upon the patient's understanding of instructions given and the doctor's ability to give clear instructions.

As might be expected, psychiatric patients are among the least reliable when it comes to taking medicines. According to three workers reporting in 1966, no more than 50 per cent of patients attending aday-hospital followed instructions faithfully. At Christmas, in particular, many patients threw away their tablets so that they could drink without fear of reactions.

These researchers writing in the journal of the College of General Practitioners found that generally patients stop taking tablets or take them irregularly simply because they forget, because they cannot remember why the drugs were prescribed, because of side-effects or because they are frightened of the potential dangers of drugs. On the other hand they concluded, some patients fear certain colours (such as black or grey) and consequently leave those tablets which frighten them.

Though some of the patients who do not take their drugs cannot be blamed for defaulting (for example, it has been suggested that elderly patients should not be expected to take more than three different drngs) other results are more surprising. For example, surveys have shown that even, in hospitals there are error rates of between 15 and 25 per cent when it comes to patients taking tablets.

One important effect of this unreliability of patients given tablets to take is that the clinical trials done on new and known drugs are of little use unless there is real evidence to show that the tablets given have actually been taken. So according to a writer in the British Medical Journal as long ago as 1965 'Drug trials in which there is no reliable check on whether the patients are taking the drugs as prescribed can be seriously misleading.'

During drug trials patients can be tested either by urine examinations or by careful counts of tablets left. Indeed, the failure of patients to take their drugs may explain why drugs which work well under trial conditions fail when given to patients under ordinary circumstances when it is not really practicable to keep such a close check on patients.

As a result of these problems it has been suggested that patients and relatives should be given a 'tablet sheet' containing clear detailsof which tablets should be taken and when. It is certainly my experience that patients who are given carefully written out details of which tablets to take can be trusted to do as they are advised. It would also help if doctors would cut down the number of pills given to patients. Too many patients are given several bottles of drugs and expected to sort out for themselves when to take them. This is not easy when one drug has to be taken three times a day, another four times a day and another twice a day on alternate days. That is by no means an unusual regime, and it is not difficult to see why patients get confused.

Taken from `The Medicine Men’ by Vernon Coleman. First published in 1975, The Medicine Men is now available again as a paperback. You can purchase a copy via the bookshop on www.vernoncoleman.com