general pharmacology special pharmacology (molekulární, buněčné, orgánové i na úrovni celého organismu) Aspirin_03 aspirin1 BASICS OF PHARMACODYNAMICS Image48 •Antagonism Competitive üligands compete for the same binding site ü c of antagonist decreases agonist effect and inversely üthe presence of antagonist incerases the amounts of agonist needed to evoke the effect Non-competitive üallosteric antagonism üirreverzible bounds ü c of agonist does not interrupt the effect of antagonist Hypersensitivity üincerase of receptor sensitivity/counts after chronic anatagonist exposure Rebound phenomenom after discontinuation of long-term administered drugs return to its original state or ↑ intensity of the original condition (hypersensitivity of receptors to endogenous ligands → up-regulation) Example: chronic administration of β blockers ü •Regulation of receptor sensitivity and counts •HYPERSENSITIVITY - INCERASE OF RECEPTOR SENSITIVITY/COUNTS AFTER CHRONIC ANTAGONIST EXPOSURE •REBOUND PHENOMENON •AFTER DISCONTINUATION OF LONG-TERM ADMINISTERED DRUGS RETURN TO ITS ORIGINAL STATE OR ↑ INTENSITY OF THE ORIGINAL CONDITION (HYPERSENSITIVITY OF RECEPTORS TO ENDOGENOUS LIGANDS → UP-REGULATION) •EXAMPLE: CHRONIC ADMINISTRATION OF Β BLOCKERS •DESENSITIZATION – REDUCED RECEPTOR SENSITIVITY/COUNTS AFTER CHRONIC AGONIST EXPOSURE •TOLERANCE – REDUCED SENSITIVITY TO THE ACTIVE SUBSTANCE, ARISING FROM THE REPEATED ADMINISTRATION OF THE DRUG (DAYS – WEEKS) → DOWN-REGULATION •EFFECT REQUIRES INCREASINGLY HIGHER DOSES •THE ORIGINAL REACTIVITY RETURNS A CERTAIN PERIOD OF TIME AFTER DISCONTINUATION OF THE DRUG •EX. OF TOLERANCE – OPIOIDS ADMINISTRATION •Receptor classification Katzung BG, 2001 rcpt_sys_nic_ag1 auto1 Image50 insulin-receptor-GLUT4_w500 BASICS OF PHARMACOKINETICS obrazek lepsi2 čas Oral administration AUC • •Effects of different bioavailability (F) on the pharmacokinetics •Presystemic elimination •First pass effect intupta http://icp.org.nz/icp_t6.html http://icp.org.nz/icp_t3.html?htmlCond=0 3l –plazma, 12l –extracel. tekutina, 42l –celk.těles.tek., 1000l – depo! Příklad léčiva s nízkým distribučním objemem Příklad léčiva s vysokým distribučním objemem http://icp.org.nz/icp_t2.html More hydrophilic compounds, sometimes active metabolites http://icp.org.nz/icp_t1.html polocas1 http://icp.org.nz/icp_t4.html biologický poločas