Final answer:
The client showing dilated pupils, elevated heart rate, and high blood pressure is likely experiencing cocaine intoxication, as these symptoms align with the effects of a stimulant drug.
Step-by-step explanation:
If a client arrives at an urgent care clinic with dilated pupils, an elevated heart rate, and high blood pressure after requesting 'zolpidem', a healthcare professional should suspect cocaine intoxication. These symptoms are indicative of a stimulant effect rather than the depressant effects associated with substances like alcohol, barbiturates, and heroin. Barbiturates in overdose typically cause symptoms such as sluggishness, incoordination, and drowsiness; these signs are not presented in the client's condition. Conversely, cocaine, a stimulant, can cause an increase in both heart rate and blood pressure and pupil dilation. Cocaine acts as a central nervous system stimulant that affects dopamine neurotransmission - significantly different from the effects of barbiturates on the GABA system.