ILLNESSES AND MEDICATIONS
Posted by recep on March 26th, 2009Functional assessment is usually considered more relevant than a medical diagnosis in determining a person’s fitness to drive. Nonetheless, some conditions—such as coronary artery disease, neurologic disease, and diabetes mellitus—as well as the use of certain medications warrant special consideration (see TABLE 112-2).
Coronary Artery Disease
Although the incidence of sudden cardiac events while driving accounts for < 1 per 1000 collisions, the quandary for the clinician is estimating the risk in an individual patient. Patients with unstable angina should not drive until symptoms have been treated medically or surgically and the angina is either stabilized or does not occur for at least 1 mo. Some antianginal medications, such as nitroglycerin, can also interfere with driving by causing precipitous drops in blood pressure. Many noncardiac drugs, such as tricyclic antidepressants, also have cardiovascular side effects that can affect driving. Patients should avoid driving for 1 to 2 days after starting such medication.
After an uncomplicated myocardial infarction or a coronary artery bypass graft operation, patients should not drive for about 1 mo. After angioplasty, a delay of 3 to 4 days is warranted. Clinicians should consult local departments of motor vehicles or state medical advisory boards for local regulations and recommendations.
Neurologic Disease
The incidence of epilepsy rises with age. About 70% of persons with epilepsy can achieve adequate control with medication, although relapses often occur with a planned withdrawal of anticonvulsant therapy. Drivers with a history of a single episode and no underlying neurologic cause are the least likely to have a recurrence. Each state has adopted regulations for drivers with a seizure history; most require some seizure-free interval such as 6 mo before reinstating driving privileges.
The incidence rates for transient ischemic attacks and strokes are highest among the elderly. An otherwise healthy person who has had a transient ischemic attack should have an attack-free interval of s 3 mo before resuming driving. After a stroke, the two concerns are residual disability and the likelihood of a recurrence. A functional assessment can help identify residual disability. The probability of recurrence warrants an event-free interval of > 3 mo before resuming driving. One year after a stroke, about 50% of patients have permanently stopped driving.
Other neurologic diseases, such as demyelinating conditions and Parkinson’s disease, may also affect driving, but the degree of disability varies widely. Patients should undergo functional assessment before any clinical decision is made.
Diabetes Mellitus
The major risk for patients with insulin-dependent diabetes is sudden hypoglycemia while driving. A diabetic with autonomic neuropathy or one who is using a ?-blocker is less able to detect the onset of hypoglycemia.
Otherwise healthy persons with diabetes who have not had a sudden episode affecting awareness for 3 yr should not require driving restrictions. Those who have had such an episode should not drive for at least 3 mo, and diabetic control should be reevaluated before driving is resumed. For insulin-dependent diabetics who have wide fluctuations in glucose levels, including documented hypoglycemia, special scrutiny is warranted. A 3-mo period of good control with no hypoglycemic events is recommended before driving is resumed.
Diabetic patients should also undergo a functional assessment to determine the effects of other diabetic complications, such as retinopathy. Because diabetic complications usually take many years to develop, therapeutic control at higher blood glucose levels is often warranted for an elderly person with diabetes of recent onset. Only extremely high glucose levels are of concern because of potential acute visual impairment.
Medications
Drugs that cause sedation can impair driving. The most common are the benzodiazepines, many of which have extraordinarily long half-lives in the elderly. Other such drugs include diphenhydramine (available over the counter) and other antihistamines, antidepressants, and opioids. Alcohol, either alone or in combination with other sedating drugs, can have a disastrous effect on driving.
