Question

What is a drug that alters synaptic transmission by blocking the reuptake of the neurotransmitter at the presynaptic membrane?

Answer 1

I think caffeine is one.

Explanation:

There is a chemical in our body called adenosine, which is one chemical that is responsible for our feeling of tiredness. When adenosine binds with our receptors, we feel sleepy. However, since the structure of caffeine is similar to adenosine, caffeine would just bind with the receptors, blocking out adenosine...
PS: Caffeine is still a drug :)