The Autonomic       Nervous System   • The Autonomic Nervous System(ANS) along with endocrine system coordinates  the regulation amd integeration of body functions.    •The ANS largerly independent (autonomous) in that its activities are not under direct conscious control. It is concenred primarily with visceral functions such as cardiac output, blood flow to various organs and digestions, which is necessary for life.    • Drugs that produce their primary therpeutic effect by mimicking or altering the functions of ANS are called autonomic drugs.    - The autonomic agents act either by stimulating portion of ANS or by blocking the action of autonomic nerves .    Nervous System overview :    • The N.S is divided into 2 anatomical divisions : The Central Nervous System which is composed of brain & spinal cord and the Peripheral Nervous System .    • Peripheral nervous system includes neurons which located outside the brain and spinal cord.    • The peripheral nervous syste

Drug Clearance It refers to the ratio of rate of drug elimination to the concentration of drug in biological fluid(C).                       CL = rate of elimination / C Rate of elimination   • For most of the drugs, elimination is not saturable & rate of drug elimination is directly proportional to concentration.                     Rate of elimination = CL x C ==> The difference between drug clearance and drug elimination is that :     • Clearance is Volume of blood cleared of drug per unit time and Elimination is amount of drug cleared from blood per unit time.  Total Body Clearance   • The total body systemic clearance , CLtotal is the sum of all clearances from drug metabolising and drug eliminating organs.                                         OR   • Dividing the rate of elimination at each organ by concentration of drug presented to it yeilds respective clearance at that organ and sum of these is total body clearance.                CLx = rate of elimination x / C      

          Drug Elimination   • Drugs must be sufficiently polar to be eliminated from the body.  • Removal of drugs from body occur via number of routes; the most important is elimination through kidney in to urine.  Renal Elimination of Drug • A drug passes through several process in the kidney before elimination, Glomerular filtration, tubular seceration , and passive tubular reabsorption.     (1) Glomerular filteration :   • Drugs enter the kidney through renal artries, which divide to form a glomerular capillary plexus. Free drug (not bound to albumin) flows through the capillary bed into bowman’s space as a part of glomerular filterate.    > Glomerular filteration rate is normally about 120mL/min. But may decrease sugnificantly in renal disease.       > pH and lipid solubility do not influence the passage of drugs into glomerular filterate.      > Variation in GFR and protein binding to drugs donot affect this process.    > water and polar compounds easily enter in gl

   Q1: Pharmacokinetics include which of the following?           (a) Drug biotranformation in the organism           (b) Influence of drugs of genes           (c) Complications of drug therapy           (d) Influence of drug on metabolism procss    Answer ~ A Q2: Pharmacokinetics include :            (a) Interaction of substances           (b) Localization of drug action           (c) Mechanism of drug action           (d) Excreation of substances     Answer ~ D Q3: Pharmacokinetics include :             (a) Unwanted effects of drugs           (b) Pharmacological effects of drugs           (c) Distribution of the drug in the organisms           (d) Chemical structure of medical agent    Answer ~ C Q4: Which kind of substances can not cross membrane by passive diffusion ?           (a) Hydrophobic substances           (b) Hydrophilic substances           (c) Non-ionized substances           (d) Lipid soluble     Answer ~ B Q5: Pharamcokinetics parameter that reflects the effects of var