1 / 26

Interactions, Chronic Effects, & Nonspecific Factors

Interactions, Chronic Effects, & Nonspecific Factors. Lesson 7. Drug Interactions. Single drug Cumulative 2 different drugs Additive physiological antagonism potentiation ~. Drug Interactions. Cumulative single drug Additive 2 different drugs as if adding individual drug effects

wwild
Download Presentation

Interactions, Chronic Effects, & Nonspecific Factors

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Interactions, Chronic Effects, & Nonspecific Factors Lesson 7

  2. Drug Interactions • Single drug • Cumulative • 2 different drugs • Additive • physiological antagonism • potentiation ~

  3. Drug Interactions • Cumulative • single drug • Additive • 2 different drugs • as if adding individual drug effects • Potentiation • 2 different drugs • combined effect greatly enhanced • as if multiplying individual effects ~

  4. Single Drug • Cumulative • repeated administration • before drug completely eliminated •  blood concentration • Timing • half-life important • Time course different • Subjective effects • blood concentrtions ~

  5. Cumulative Effects Hi Response Lo Time

  6. Multiple Drug Interactions • Physiological antagonism • drugs have opposing effects • Additive effects • drugs have same effects • Potentiation • synergistic • greater than expected by individual drug effects ~

  7. Physiological Antagonism A A + B Hi Drug Effect B Lo

  8. Additive Effects A + B B A Drug Effect

  9. Potentiation A + B B Drug Effect A

  10. Chronic Use: Tolerance • After repeated use • Decreased response to the same dose • Compensatory responses • Not at a uniform rate • different for each drug effect ~

  11. Tolerance A B 100 % population 50 0 0 X DRUG DOSE

  12. Types of Tolerance • Tachyphylaxis • rapid & transient • usually between 1st 2 doses • NT depletion, receptors occupied • Drug Disposition Tolerance • enzyme induction ~

  13. Types of Tolerance • Pharmacodynamic Tolerance • decreased NT synthesis • Down-regulation of receptors • Behavioral Tolerance • Volitional vs. Associative • Cross Tolerance • tolerance to 1 drug  also to a 2d • e.g., alcohol & phenobarbitol ~

  14. Chronic Use: Tolerance • Repeated use:  response to same dose • Compensatory responses • Not at a uniform rate • Tachyphylaxis • Drug disposition • Pharmacodynamic • Behavioral • Cross-tolerance~

  15. Chronic Use: Sensitization • Increased response to a repeated dose • Reverse tolerance • Cocaine & amphetamine • motor activation • Don’t know mechanism • conditioning involved • increased NT & receptor synthesis? ~

  16. Tolerance / Sensitization • Tolerance for CNS depressants? • Sensitization for CNS stimulants? • It depends! • Alcohol: both • Cocaine: both

  17. Chronic Cocaine in Chicks

  18. Which curve shows sensitization? A B 100 % population 50 0 0 X DRUG DOSE

  19. Other Sources of Variability • Nonspecific factors • Organism • Psychological • Environmental • Task ~

  20. Organism Variables • Weight • Sex & Hormonal states • Interspecies differences • Intraspecies differences • codeine analgesia • Asian men < European • metabolism & clearance ~

  21. Organism Variables • Age • Disease • Nutrition • Biological rhythms ~

  22. Other Nonspecific Variables • Psychological • Expectations • set • Placebo effects • Environmental • Setting • Task • Rate-dependent effects ~

  23. Rate Dependency • Interaction of drug... & baseline rate of behavior • ADHD & ritalin • stimulant to treat hyperactivity? ~

  24. Different Effects, Same Dose • Why? • initial activity of system • Low activity in system • drug increases effects • High activity in system • drug may decrease effects ~

  25. drug dose drug dose x x max x Behavior x min lo hi Drug amount (dose) Difference in baseline activity.

  26. Should you take a drug? • Rational judgment process • But often not • Many factors involved • Learning: • Classical & Operant Conditioning ~

More Related