study guide 1.pptx

PSYCHOPHARMAC OLOGY PSYCHOTROPIC/PSYCHOACTIVE AGENTS can be: • ENDOGENOUS i.e. INTERNAL vs. • EXOGENOUS i.e. EXTERNAL AGENTS • ENDOGENOUS = NEUROTANSMITTERS • EXOGENOUS = DRUGS PSYCHOPHARMAC OLOGY NEUROTRANSMITTERS: are chemical compounds produced at varying sites within the body (i.e., endogeno...

PSYCHOPHARMAC OLOGY PSYCHOTROPIC/PSYCHOACTIVE AGENTS can be: • ENDOGENOUS i.e. INTERNAL vs. • EXOGENOUS i.e. EXTERNAL AGENTS • ENDOGENOUS = NEUROTANSMITTERS • EXOGENOUS = DRUGS PSYCHOPHARMAC OLOGY NEUROTRANSMITTERS: are chemical compounds produced at varying sites within the body (i.e., endogenous) having specific effects at specific locations within the body DRUGS: are chemical compounds from outside the body (i.e., exogenous) which have selective biological activity within the body PSYCHOPHARMAC OLOGY DRUGS biological activities (response) are dependent upon their DOSE-RESPONSE relationship within the body i.e. • the degree of biological activity is dependent on the amount of drug administered • a drug’s action depends upon how much of the drug reaches its site of action per unit of time KEY CONCEPTS IN PHARMACOLOGY PSYCHOPHARMAC OLOGY PHARMACO-KINETICS i.e., • what the body does to the drug PHARMACO-DYNAMICS i.e., • what the drug does to the body at the cellular level PSYCHOPHARMAC OLOGY DOSE-RESPONSE RELATIONSHIP is the basis for the THERAPEUTIC INDEX (TI) of a drug • TI of a drug derived from the interval between the drug’s 50% effective dose (ED) and its 50% toxic dose (TD)or lethal dose (LD), i.e. , the interval between ED50 and TD50 or LD50 • TI =(LD50/ED50) must exceed 7 to prevent overdose or death PSYCHOPHARMACOL OGY Formula for the therapeutic index (TI) is a ratio derived from the lethal dose (LD) or toxic dose (TD) over the effective dose (ED) at 50 percent. Example: • If the lethal dose of a drug is 700 mgs. and • The effective dose is 100 mgs. 700 mgs. 100 mgs. This equals a TI of 7 THERAPEUTIC INDEX of a drug (PHARMACO-KINETICS) depends upon three things: PSYCHOPHARMAC OLOGY • ROUTE OF ADMINISTRATION • RATE OF ADMINISTRATION • RATE OF ABSORPTION ROUTE OF ADMINSTRATION has two classes: PSYCHOPHARMAC OLOGY • ORAL (digestive aka p.o. = per os) and • PARENTERAL (nondigestive) e.g., anal, intravenous (IV), intramuscular (IM), inhalation, subcutaneous (SC), sublingual (SL), or transdermal (patch) PSYCHOPHARMAC OLOGY RATE OF ADMINISTRATION (PHRMACO-KINETICS) depends on the biological half-life of the drug i.e. when half of the drug’s compound is eliminated from the body e.g., every 8 hrs., 12 hrs., 24 hrs. • This is how the dosing schedule is determined: q.i.d.,(6x4) b.i.d. (12x2), once at day RATE OF ABSORPTION (PHARMACO-KINETICS) depends on PSYCHOPHARMAC OLOGY the physical state of the drug i.e.: • SOLID (slowest rate) • LIQUID (medium rate) • GAS (fastest rate) • Rate chosen depends on desired effect e.g. rapid effect = gas= general anesthetic PSYCHOPHARMAC OLOGY RATE OF ABSORPTION Absorption complete when a drug’s concentration in general circulation is equal to its concentration at the site of administration aka as a drug’s steady state. • A drug’s steady state usually equals 4-5 times the biological half-life of the drug PSYCHOPHARMAC OLOGY ABSORPTION-ELIMINATION CYCLE Once absorption is complete the drug is eliminated from the body via its physical state: • Gases eliminated via exhalation (lungs) • Liquids and solids eliminated via enzymatic degradation i.e. liver uses 450 enzymes to transform drugs then kidneys void them PSYCHOPHARMAC OLOGY • DRUG RESPONSE SPECIFICITY-is the result of drug-receptor affinity i.e., lock-key model • DRUG RESPONSE VARIABILITYmany factors influence a drug’s response e.g., age, gender, health, genetics, past experience with the drug and similar drugs Drugs are researched: 1) for their therapeutic effects in treatment of mental disorders PSYCHOPHARMAC OLOGY 2) to gain insight into mechanisms of the nervous system e.g. psychotomimetic 3) to understand and prevent the nature of abuse/addiction PSYCHOPHARMAC OLOGY: DRUG CLASSIFICATION Two Comprehensive Classes of Drugs: • Excitatory • Inhibitory Five General Sub Classes: • Stimulants • Antidepressants • Depressants • Tranquilizers • Hallucinogens STIMULANTS: PSYCHOPHARMAC OLOGY: DRUG CLASSIFICATION 1) XANTHINES 2) AMPHETAMINES/ ANTIOBESITY 3) CONVULSANTS/ ANTICONVULSANTS