General Pharmacology

  1. What are the effects of noncompetitive inhibitors?
    • - Do not resemble the substrate.
    • - Can not be overcome by increasing substrate concentration
    • - Do not bind the active site
    • - Decrease Vmax
    • - Do not change Km
    • - Decrease efficacy
  2. What are the effects of competitive inhibitors?
    • - Resemble the substrate
    • - Can be overcome by increasing substrate concentration
    • - Bind the active site
    • - Do not change Vmax
    • - Increase Km
    • - Decrease potency
  3. Km reflects the _________ of the enzyme for the substrate.
    affinity
  4. Vmax is directly proportional to the _____________.
    enzyme concentration
  5. Volume of distribution
    (definition and equation)
    • - amount of drug in the body to the plasma concentration
    • - Vd of protein-bound drugs can be altered by liver and kidney disease

    Vd = amount of drug in the body/plasma drug concentration (units L)
  6. Where do drugs distribute with low Vd, medium Vd, and high Vd?
    • Low Vd: distribute in blood
    • Medium Vd: distribute in extracellular space or body water
    • High Vd: distributes in tissues
  7. Clearance
    • - relates the rate of elimination to the plasma concentration
    • Cl = rate of elimination/plasma drug concentration
    • = 0.7Vd / t1/2
  8. Half Life
    • - time required to change the amount of drug in the body by 1/2 during elimination
    • t1/2 = 0.7Vd/Cl (in hours)
    • - 1 t1/2: 50% concentration
    • - 2 t1/2: 75% concentration
    • - 3 t1/2: 87.5% concentration
    • - 4 t1/2: 94% concentration
  9. Loading Dose

    Maintenance Dose
    • Loading Dose = CpVd/F
    • Maintenance Dose = CpCl/F

    • Cp = target plasma concentration
    • F = bioavailability

    • - in patients with impaired renal or hepatic function,
    • loading dose remains the same
    • maintenance dose decreases
  10. Elimination of Drugs
    • Zero Order - rate of elimination is constant, regardless of concentration
    • - Cp decreases linearly with time
    • - phenytoin, ethanol, aspirin

    • First Order - rate of elimination is proportional to the concentration
    • - Cp decreases exponentially with time
  11. Urine pH and Drug Elimination
    • Ionized Species Get Trapped
    • Weak Acids
    • - trapped in basic environments
    • - treat overdose with bicarbonate
    • - pH > pKa nonprotonated form (ionic)

    • Weak Bases
    • - trapped in acidic environments
    • - treat overdose with ammonium chloride
    • - pH<pKa protonated form (ionic)
  12. Phase I and Phase II Metabolism
    • Phase I
    • - reduction, oxidation, hydrolysis
    • - slightly polar, water soluble metabolites
    • - cytochrome P450

    • Phase II
    • - acetylation, glucuronidation, sulfation
    • - usually yields very polar, inactive metabolites (renally excreted)
    • - conjugation

    Geriatric patients lose Phase I first
  13. Efficacy vs. Potency
    Efficacy - maximal effect a drug can produce (Vmax)

    Potency - amount of drug needed for a given effect (Km)
  14. How do partial agonists effect potency and efficacy?
    • - acts on the same receptor system as the full agonist but has a lower maximal efficacy, regardless of the dose
    • - potency is an independent factor; therefore, a partial agonist can have lower potency, equivalent potency, or higher potency
  15. Therapeutic Index
    • TI = Ld50/Ed50
    • - want a higher TI
    • - TILE pneumonic
  16. Acetylcholine Receptors
    • Nicotinic ACh Receptors - ligand gated Na+/K+ channels
    • - NN - autonomic ganglia
    • - NM - neuromuscular junctions

    • Muscarinic ACh Receptors - G-Protein coupled receptors
    • - 5 subtypes: M1 - M5
  17. Alpha-1 Receptor
    • - Sympathetic
    • - Gq protein class (IP3 increases Ca2+, DAG increases Protein Kinase C)
    • - increase vascular smooth muscle contraction
    • - mydriasis (pupillary dilator muscle contraction)
    • - increase sphincter contraction
  18. Alpha-2 Receptor
    • - Sympathetic
    • - Gi protein class (decreases cAMP and PKA)
    • - decrease sympathetic outflow
    • - decrease insulin release
  19. Beta-1 Receptor
    • - Sympathetic
    • - Gs protein class (increases cAMP and PKA)
    • - increases heart rate
    • - increases contractility
    • - increases renin release
    • - increases lipolysis
  20. Beta-2 Receptor
    • - Sympathetic
    • - Gs protein class (increases cAMP and PKA)
    • - vasodilation
    • - bronchodilation
    • - increase heart rate
    • - increase contractility
    • - increase lipolysis
    • - increase insulin release
    • - decrease uterine tone
  21. M1 Receptor
    • - Parasympathetic
    • - Gq protein class (IP3 increases Ca2+, DAG increases Protein Kinase C)
    • - CNS
    • - enteric nervous system
  22. M2 Receptor
    • - Parasympathetic
    • - Gi (decrease cAMP and PKA)
    • - decrease heart rate
    • - decrease contractility of atria
  23. M3 Receptor
    • - Parasympathetic
    • - Gq protein class (IP3 increases Ca2+, DAG increases Protein Kinase C)
    • - increase exocrine gland secretions
    • - increase gut peristalsis
    • - increase bladder contraction
    • - bronchoconstriction
    • - miosis (pupillary sphincter muscle contraction)
    • - accomodation (ciliary muscle contraction)
  24. D1 Receptor
    • - Dopamine
    • - Gs protein class (increase cAMP and PKA)
    • - relaxes renal vascular smooth muscle
  25. D2 Receptor
    • - Dopamine
    • - Gi protein class (decrease cAMP and PKA)
    • - modulates transmitter release (especially in the brain)
  26. H1 Receptor
    • - Histamine
    • - Gq protein class (IP3 increases Ca2+, DAG increases Protein Kinase C)
    • - increase nasal and bronchial mucus production
    • - contraction of bronchioles
    • - prutitis
    • - pain
  27. H2 Receptor
    • - Histamine
    • - Gs protein class (increase cAMP and PKA)
    • - increase gastric acid secretion
  28. V1 Receptor
    • - Vasopresssin
    • - Gq protein class (IP3 increases Ca2+, DAG increases Protein Kinase C)
    • - increase vascular smooth muscle contraction
  29. V2 Receptor
    • - Vasopressin
    • - Gs (increase cAMP and PKA)
    • - increase water permeability and reabsorption in the collecting tubules of the kindney
Author
eefynan
ID
76187
Card Set
General Pharmacology
Description
First Aid 2010 Pages 228 - 233
Updated