Over the counter medication
June 2005
Misuse
Misuse of OTC drugs is of concern in a minority of users, as this next section will illustrate. The potential for misuse of OTC drugs has also been the subject of recent media stories. It is important that healthcare professionals and the public are aware of these issues and work in partnership to reduce them.
Although clear, written, and often verbal guidance on OTC medicines is given, patients may deliberately or inadvertently take the medicine differently from the labelled instructions and recommendations. Deliberate misuse would include the taking of a drug purely for recreational effect (eg an opioid, or an antihistamine), or exceeding the recommended OTC dose, or duration of treatment, to experience enhanced medicinal effects (eg an analgesic or a sleep aid). Inadvertent misuse could include long-term regular use of a drug with increased risk of developing side effects, (for example NSAID use). While products sold from pharmacies will be subject to supervision from the pharmacist, who may use a variety of protocols to maximise benefit and minimise harm to patients, this is not the case for products sold from general retail outlets. Pharmacists’ Code of Ethics requires that, ‘pharmacists and their staff must be aware of the abuse potential of certain OTC products and should not supply where there are reasonable grounds for suspecting misuse’ (RPSGB 2004). While reasonable grounds are not defined within the Code, examples might be that customers were obviously purchasing quantities in excess of those required under a standard dosing schedule, or regular purchase without apparent clinical indications for using the drug.
Research shows that community pharmacists are concerned about possible misuse of OTC medicines and use a variety of strategies to detect and prevent this, including registers of use, refusing sales (in line with their Code of Ethics), removing certain products from display or not stocking them at all (Pates et al 2002, Hughes et al 1999). Work conducted in Scotland in 1995 and 2000 (Matheson et al 2002) found that over two thirds of community pharmacists reported having suspicions of the misuse of OTC medicines, confirming an earlier small survey in Wales (Pates et al 2002). This was particularly the case in urban areas. Four broad categories of products were mentioned: antihistamines, opioids, mild stimulants, and laxatives. Throughout Scotland, the misuse of antihistamine-containing products was suspected by more than half of all community pharmacists: this could be excessive use (outside the recommended dosage) for sleep disturbances or to mask other drug dependence. There was a reduction in the suspected misuse of codeine linctus across the two surveys, although not other codeine containing products. Similarly, sleep aids and codeine containing analgesics were products found to generate the most concern in another UK study (Phelan et al 2003). An international survey of strategies used and suggested by community pharmacists to reduce misuse of OTC sleep aids identified some key areas. These included improving access to current information, improved staff training, and addressing the issues of OTC sales from non-pharmacy outlets and over the internet (McBride et al 2003). Pharmacists must, therefore, continue to be vigilant regarding the potential for inappropriate or excessive consumption or use of these medicines, in line with their Code of Ethics.
Drugs with a serious potential for addiction are covered by the Misuse of Drugs Act, and their distribution controlled carefully through formal prescribing. Small doses of controlled drugs, such as dihydrocodeine, codeine and morphine are, however, still allowable OTC as components of compound preparations. There are still several proprietary brands of antidiarrhoeals for example, which contain small amounts of morphine, and cough remedies which contain codeine. Codeine and dihydrocodeine are constituents of some OTC analgesics, in combination with aspirin, paracetamol or ibuprofen. Pharmacists are reported to be concerned about drug misusers attempting to purchase codeine-containing analgesics (Pates et al 2002, Hughes et al 1999).
There has been some research specifically into the overuse of sleep aids. First generation antihistamines (FGAs) including diphenydramine and promethazine are available over the counter in several countries as sleep aids. Such products may be inadvertently misused by people whose sleep disorder is other than a temporary problem. They may also be deliberately misused by people dependent on other medicines. A UK study found that some users had been taking the sleep aid for longer than the recommended time (Phelan et al 2003). Usage of antihistamine sleep aids in the USA is higher than that of benzodiazepines and a US study of people with sleep problems found that 6.4 per cent of men and 11.4 per cent of women reported using OTC sleep aids (Pillitteri et al 1994). The percentages of men and women reporting using alcohol to help them sleep were higher, at 23.4 per cent and 10.9 per cent. Just over a quarter of people aged over 60 in a Canadian survey of patients during hospital or pharmacy visits had used an OTC sleep aid within the last year (Sproule et al 1999). The same study found that 19 per cent of people who reported using a sleep aid cited paracetamol and 13 per cent alcohol.
Sleep aids and analgesics containing opioids may also be deliberately misused by people dependent on other medicines, but there is probably most concern about inadvertent dependence on such products developing following prolonged use. For example, the long-term use of analgesics in the treatment of chronic daily headache can lead to inadvertent dependence and rebound headache on withdrawal. This applies to both OTC and prescribed analgesics.
There are no epidemiological data to enable reliable estimates of incidence or prevalence of OTC medicine misuse. A support group for people dependent on OTC medicines, Over Count, estimated that 30,000 people might be affected by such dependence in Great Britain (Grieve D 2004). The lack of data on usage of OTC analgesics across the population of users, however, means it is impossible to support or refute this estimate. This again supports the need for a systematic approach to recording use of OTC medicines and their pharmacovigilance.
The individual case histories collected by Over Count do indicate that some users of OTC analgesics whose symptoms are not controlled within the parameters of recommended timescale and dose need support in obtaining further information and advice. Over Count has advocated that product labelling should warn of the possibility of dependence. Others have argued, however, that such labelling would be counter-productive (for example, deterring use by people who might benefit) and could encourage misuse (Adcock H 2001). Health professionals need to be aware of the small possibility of dependence on OTC medicines and of what support patients might need to stop using the medicine.
In summary, the important issue is probably whether misuse is deliberate or inadvertent. It is necessary to balance the important benefits of the OTC availability of effective treatments, to both the NHS and the majority of the population, against the risk of misuse. The efforts of regulators and healthcare professionals should go into ensuring that inadvertent misuse is avoided and that deliberate misuse (ie those taking a drug for recreational effect or enhanced medicinal effects) is identified early and dealt with appropriately.