Pharmacodynamics - The actions of drugs within the body. Drugs enter and act within the body by binding with cell receptors, specialized fragments of proteins that instruct the cell to take or not take specific actions. This binding process, called selectivity, limits and directs the effects of drugs. Proteins are the basic components of the body’s biochemical messengers, hormones and neurotransmitters. The interactions they initiate are often intricate cascades that influence numerous biochemical processes (such as ion passage for cell communication) as well as DNA encoding and transcription (cell function and replication). Numerous factors influence the unfolding of these cascades, from a person’s general health status and existing health conditions to other drugs the person is taking. For example, INSULIN RESISTANCE and DIABETES affect the energy accessible to cells to carry out the functions of cellular METABOLISM, altering the processes and outcomes of receptor binding. Through different mechanisms HYPOTHYROIDISM slows and HYPERTHYROIDISM accelerates cellular metabolism, also affecting receptor binding. Pharmacodynamics gives doctors and pharmacists the ability to assess how individuals may react to specific drugs, depending on their unique health profiles.
See also ALCOHOL INTERACTIONS WITH MEDICATIONS; BIOAVAILABILITY; CYTOCHROME P450 (CYP450) ENZYMES; HORMONE; NEURON; NEUROTRANSMITTER; PHARMACOKINETICS.