An increasing number of drugs can now be bought over the counter from pharmacies. Many of these preparations (e.g., cough mixtures and deconges-tants), contain drugs that can cause sedation, particularly the older antihista-mines (e.g., chlorpheniramine). The newer nonsedating antihistamines, such as terfenadine and astemizole, generally do not impair driving. However, one study that measured driving performance across differing doses of terfenadine found that performance was impaired at very high doses (240 mg), stressing the need to establish the behavioral effects of drugs over a range of doses (85). The second-generation group of antihistamines is less lipophilic than the previous generation and thus cross the blood-brain barrier less readily, which accounts for the lower levels of sedation observed with the newer drugs. Thus, although the second-generation antihistamines generally produce less sedation than first-generation compounds, if therapeutic doses are exceeded, the so-called nonsedating antihistamines become sedating and can impair driving.
Was this article helpful?
This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.