Medication Use and Driving Risks by Tammie Lee Demler, BS Pharm, Pharmd

CONTINUING EDUCATION Medication Use and Driving Risks by Tammie Lee Demler, BS Pharm, PharmD pon successful completion of this ar- the influence of alcohol has Useful Websites ticle, pharmacists should be able to: long been accepted as one 1. Identify the key functional ele- of the most important causes ■ www.dot.gov/ or http://www.dot.gov/ ments that are required to ensure of traffic accidents and driv- odapc/ competent, safe driving. ing fatalities. Driving under Website of the U.S. Department of 2. Identify the side effects associated with pre- the influence of alcohol has Transportation, which contains trends Uscription, over-the-counter and herbal medi- been studied not only in ex- and law updates. It also contains an cations that can pose risks to drivers. perimental research, but also excellent search engine. 3. Describe the potential impact of certain medi- in epidemiological road side ■ www.mayoclinic.com/health/herbal- cation classes on driving competence. studies. The effort that society supplements/SA00044 4. Describe the pharmacist’s duty to warn re- has made to take serious le- Website for the Mayo Clinic, with garding medications that have the potential to gal action against those who information about herbal supplements. impair a patient’s driving competence. choose to drink and drive It offers an expert blog for further exploration about specific therapies and 5. Provide counseling points to support safe driv- has resulted in the significant to receive/share insight about personal ing in all patients who are receiving medication. deterrents of negative social driving impairment with herbal drugs. stigma and incarceration. ■ www.icadts.nl/ Upon successful completion of this article, phar- Recently, laws in some states Website of the International Council on macy technicians should be able to: were strengthened even fur- Alcohol, Drugs and Traffic Safety, which 1. Identify the key functional elements that are ther by making driving while works to reduce morbidity and mortality required to ensure competent, safe driving. intoxicated (DWI) a felony if brought about by use of alcohol and 2. List side effects associated with the use there is a child in the car. drugs by operators of vehicles using all of herbal remedies, over-the-counter and While the impact of modes of transportation. prescription medications that can pose risks alcohol on driving abilities to drivers. is well known, there are few 3. Describe the potential impact of certain medi- epidemiologic studies about the role of herbal remedies, cation classes on driving competence. over-the-counter and prescription drugs in motor vehicle 4. Describe situations when the pharmacist accidents. There are some lab experiments in which the should be alerted to counsel patients on the therapeutic doses of several drugs have been shown potential of a medication to impair driving to impair psychomotor skills related to driving. It is also competence. important to note that many medications may potentiate the impairing effects of alcohol and other drugs. Less INTRODUCTION attention has been given to driving under the influence We are all well aware of the impact of drink- of medication, whether prescription or OTC medication. ing and driving through the media coverage Illicit drug use also seems to receive less media attention of drinking related accidents and through the than alcohol, and is much more difficult to detect. Field public service announcements sponsored by sobriety tests and breathalyzer detection systems have law and advocacy groups. Driving while under been in place for some years to detect alcohol, but as yet www.americaspharmacist.net March 2012 | america’s PHARMACIST 35 there is no valid test to measure impairment from other severity of the effects differ between the medica- substances. Departments of motor vehicles (DMV) across tions studied, often depending on the half lives, the United States have tried to address this issue, and the dose, and formulation of the medications. New York state DMV medical advisory board tackled the There has been research looking at the issue of the impact of OTC medications on driving as a residual effects of benzodiazepines and non- specific focus of community outreach years ago. benzodiazepine hypnotics (z-hypnotics), using The issue of tracking the absolute impact of medi- single dose temazepam 20 mg and eszopiclone cations on driving is difficult unless there is an accident 7.5 mg in older drivers. Even though these two which requires further investigation and confirmatory medications would be expected to cause sig- blood tests that can be evaluated. The question remains, nificant residual side effects equally, the results however, whether appropriate use of herbal remedies and of the study do not support this hypothesis. The FDA approved medications poses a sufficiently significant study reported that single dose temazepam- potential hazard to suggest that these agents should not impaired driving performance in elderly patients be used while driving. Researchers must consider that the until 10 hours after bedtime administration, same dose of a certain medication can have wide vari- whereas eszopiclone impaired driving signifi- ability in both the intended therapeutic action of the drug, cantly until 11 hours after the dose. but also the side effects for individuals of different ages Antidepressants were evaluated for similar and states of health. People often drive without adequate effects. In a study of nefazodone, it was found knowledge of the degree of impairment their prescribed that impairment is the same for both elderly and and OTC medications can have on their driving skills. younger patients. It may be suggested that the Individual differences in the absorption, distribution, testing parameters may not have been sensitive metabolism and elimination of medications all cause enough to detect effects on specific features a difference in the effect of a drug on the body. As we of elderly drivers, especially when the same age, these differences become even more pronounced. medications have demonstrated moderate Coupled with the age-specific decline in physical and impairment in younger subjects. Some studies cognitive ability to drive and operate machinery, changes have examined the effects of chronic use versus of organ function and lean body mass can also play a role intermittent use of benzodiazepines with no dif- in driving deficits as we grow older. However, it is impor- ference noted, so caution should be extended tant to note that organ changes can be seen in younger even for those who use sedating medications on patients with chronic disease and comorbidities condi- a regular basis. tions as well. The impairment of behavioral, mental and Another factor to be considered is that while physical functions such as psychomotor performance, some drugs known to cause driving impairment visual perception, attention, memory and information pro- can be isolated and avoided, other substances cessing are all potential issues with medications. Aging which cause significant impairment are com- in itself is not the key to impairment. However, diseases bined with less impairing substances. Alcohol that are more likely to be experienced with increasing age, is known to impair driving, but also amplifies such as dementia and other medical comorbidities that what might be minor or insignificant impairment. can impact physical strength and executive function, are Multi-ingredient combinations may be perceived the real factors which must be considered as potential by the general population as less danger- contributions to decreased driving competence. With the ous products and sold to patients who would number of aging drivers expected to increase over time, otherwise not use the single source product. An these factors must be taken into account. One would example of this can be seen with OTC products expect that medications most commonly associated such as the combination of acetaminophen and with sedation, such as sleep medicines and/or sedative- diphenhydramine, which is marketed for pain hypnotics, would significantly increase risk. However, even relief at bedtime while improving sleep. The with these well-known offending drugs, the duration and diphenhydramine portion of this product is used 36 america’s PHARMACIST | March 2012 www.americaspharmacist.net alone as an OTC sleep aid. Other OTC medica- as being able to see a red light as a warning with discrete tions, such as anti-diarrheals, can also be very meaning when compared to a streetlight without meaning. sedating and impairing, so no medication should be considered entirely safe without consulting Visual Attention first with a health care professional. Another well- Visual attention is defined as the selection of visual stimuli studied category of impairing medication seen based on location in space. This is a key function for detect- prescribed in combination with other medica- ing road side targets, and impairment in this category can tions is the benzodiazepine class. Research be a reliable early indicator of many disorders including, but has demonstrated that use of multiple sedat- not limited to, dementia. Tests to determine the intactness of ing agents, such as duplicate benzodiazepine visual attention are available to specialists, however, are not therapy and benzodiazepines combined with widely available to most general practitioners. one or more antidepressants increases the risk Visual attention requires being able to pay attention of traffic

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