Medications used in the treatment of nervous system disorders typically modulate neurotransmitter function or action potential propagation and alter neurologic function. This chapter reviews the principles of pharmacokinetics, the major targets for drug action to provide a basis for understanding how medications exert their action, and disease-specific treatments. An understanding of the pharmacokinetic principles of neurologic medications is important for prescribing and ordering medication. Multiple routes of administration, including intravenous, sublingual, intramuscular, subcutaneous, rectal, oral, and transdermal, are available for delivery of neurologic medications.