Given Kerry Kennedy’s recent court appearance for the charge of drunk driving, there has been renewed interest in sleeping pills’ known effect of impairing driving. The most common prescription, Ambien, or zolpidem as the generic is known, was implicated in Kennedy’s car crash earlier this summer. She reported having accidentally consumed the small sleeping pill in the morning, in lieu of her thyroid medication.
Zolpidem is a controlled substance available by prescription only, and specifically is a non-benzodiazepine hypnotic generally recommended for short-term treatment (of up to 4 weeks) of insomnia. Zolpidem shortens the time it takes to fall asleep, or sleep latency, and prolongs total sleep time in patients with insomnia. It also has weak anti-seizure properties.
The drug manufacturer Sanofi-Aventis states that patients should be cautioned against engaging in hazardous occupations requiring complete mental alertness or motor coordination, such as driving a motor vehicle, if they haven’t had at least 7-8 hours of sleep after taking the medication. Within the first 4-5 hours, zolpidem can produce significantly impaired coordination, reaction times and cognition following single oral doses of 10-20 mg. However, no significant adverse effects were observed during a 1.5 hour driving test on a rural road, 10-12 hours after drug administration. In reported cases of driving impairment in which zolpidem was the only drug detected, the mean blood concentrations of zolpidem was 0.65 mg/L. For context, the average blood concentration produced by the usual 10 mg dose at 1.6 hours after intake is 0.12 mg/L.
Symptoms of ambien-impairment while driving include weaving, lane travel, slow and slurred speech, slow reflexes, dazed appearance, disorientation, confusion, loss of balance and coordination, loss of short-term memory, blacking out, dilated pupils, double vision, poor performance on field sobriety tests, poor attention, and an inability to stand or walk unassisted.
Given this drug’s otherwise long track record and generally safe profile, patients need to beware of proper dosing instructions, in order to avoid the rare mishap suffered by Kennedy.