It is a common complication of diabetes. The most common cause is poorly controlled blood sugar over time. Diabetic nerve pain can take years to develop. In the early stages, you may have no signs at all, and then only start to feel a tingling or numbness in your feet. As it progresses, you may also feel the pain in your hands and it is often worse at night.
Lastly, the aging process affects how drugs are excreted (eliminated) from the body. The elderly have a decrease in kidney function and blood flow to the kidneys. Due to this decrease, it is common to decrease the dose of drugs that are eliminated by the kidneys.
HOW DRUGS AFFECT NEUROTRANSMITTERS. Dopamine appeared very early in the course of evolution and is involved in many functions that are essential for survival of the organism, such as motricity, attentiveness, motivation, learning, and memorization.ut not all drugs increase dopamine levels in the brain in the same way. 1  Some substances imitate natural neuromediators and take their place on their receptors. 2  Other substances increase the secretion of natural neuromediators. 3  Still other substances block a natural neuromediator.