Final answer:
Some drugs indeed have multiple pharmacologic actions, acting as agonists for certain neurotransmitters while as antagonists for others. GABA-activating drugs such as benzodiazepines and barbiturates typically have depressant effects.
Step-by-step explanation:
Some drugs may have more than one pharmacologic action. This statement is true. Drugs can affect multiple systems or pathways in the body and therefore can have multiple pharmacological actions. For instance, a single drug might work as an agonist for one type of receptor and as an antagonist for another. Agonists increase the activity of neurotransmitters, whereas antagonists decrease it. Drugs that act by mimicking the effects of the neurotransmitter acetylcholine (ACh) at preganglionic synapses can cause an overall sympathetic effect in the body. On the other hand, drugs that activate receptors for the neurotransmitter gamma-aminobutyric acid (GABA) usually have a depressant effect because GABA is primarily inhibitory in the central nervous system. Examples of drugs affecting the GABA system include benzodiazepines and barbiturates.
Anxiolytics, such as benzodiazepines, are prescribed by physicians to reduce anxiety and these usually have a sedative effect because they enhance GABA activity. The nature of drug interactions can also be both synergistic, where drugs work together and enhance each other's effects, and antagonistic, where they work against each other, potentially reducing efficacy or increasing toxicity.