An overdose of which type of drug can result in central nervous system depression; shallow respiration; cold, clammy skin; and dilated pupils?

The characteristics described in the question align closely with the effects of sedatives and tranquilizers. These substances, which include medications like benzodiazepines or barbiturates, act as depressants on the central nervous system. When an individual overdoses on these drugs, the result can lead to significant respiratory depression, as the body’s drive to breathe decreases. This is commonly seen alongside shallow respiration, as the respiratory rate slows considerably.

In addition to affecting breathing, an overdose of sedatives and tranquilizers often results in cold, clammy skin due to the slowing of blood circulation and reduced metabolic rate. Furthermore, the effect of these drugs on the body's autonomic responses may lead to dilated pupils, contrasting with other types of drugs that can induce pinpoint pupils.

Understanding these effects is critical for EMTs, as identifying the signs and symptoms associated with specific drug overdoses allows for prompt and appropriate medical interventions, including airway management and respiratory support if necessary.