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Pharmacology

Pharmacology. Module #1 General Principles . Chapter 1. Information, Sources, Regulatory Agencies, Drug Legislation and Prescription Writing. What is Pharmacology?. Study of drugs and their effects on living organisms. Why study pharmacology?.

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Pharmacology

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  1. Pharmacology Module #1 General Principles

  2. Chapter 1 Information, Sources, Regulatory Agencies, Drug Legislation and Prescription Writing

  3. What is Pharmacology? • Study of drugs and their effects on living organisms

  4. Why study pharmacology? • Knowledge about pharmacology is imperative in order for the dental professional to perform important functions such as: • Obtaining health histories • Administering drugs in the office • Handling emergency situations • Planning appointments • Non-prescription medications • Discussing drugs

  5. What are drugs? • Any substance taken by mouth, injected into a muscle, the skin, a blood vessel or cavity of the body, or applied topically to treat or prevent a disease or condition. • Chemical substances that act on biologic systems to produce an effect • stimulate or depress cells

  6. Drug Names • Trade name • Registered trademark • Capitalized • generic name • U.S. Adopted Name Council • official name • lower case • Chemical name • chemical structure

  7. Calvin Klein Denims Gap Levi’s Silver Jeans Which names are generic?

  8. Brand vs. Generic Drugs • Patients may want to know: • Are they the same? • Do they work equally as well?

  9. Equivalency Laws • FDA requires that the active ingredients in generic products enter the bloodstream at the same rate as the brand name drug • To be sold in the US, generic drugs must be proven biologically and therapeutically equivalent to the brand name drug

  10. Types of Equivalence • Chemical equivalent • meet same chemical & physical standards • may not have same bioavailability • Biologic equivalent • similar concentrations in blood & tissues • Therapeutic equivalent • equal therapeutic effect

  11. Video- Brand vs. Generic • You Tube • https://www.youtube.com/watch?v=27oUml96BlQ

  12. Federal Regulatory Agencies • Food and Drug Administration (FDA) • Grants approval so that drugs can be marketed • Must be proven safe and effective • Quality control • Federal Trade Commission • Prohibits false advertising • Drug Enforcement Administration (DEA) • Regulates substances that have potential for abuse

  13. Clinical Evaluation of New Drugs • Animal studies • Phase 1 • Small # of healthy volunteers- determine safety • Phase 2 • Larger #- determine effectiveness • Phase 3 • Sick patients- determine dosage • Phase 4 • Post-marketing surveillance- toxicity?

  14. Controlled Substances • 5 schedules according to their abuse potential • Schedule 2 prescriptions: • Must be hand-written and signed • Cannot be called in to the pharmacy (patient must hand-deliver) • Never any refills (new Rx every time) • Schedule 3-5 prescriptions: • May be phoned in, no more than 5 refills

  15. Schedule of Controlled Drugs

  16. Prescription Writing • Dental practitioners need to be familiar with the basics of prescription writing for the following reasons: • If written correctly, it will save time • Carefully written prescriptions have fewer mistakes • Unusual prescriptions can be explained, saving the patient and pharmacist time

  17. Prescription Basics • Metric system • Milliliters (ml) • 1 tsp= 5ml • Milligrams (mg)

  18. Common Abbreviations • See page 9 • Table 1-5 • Know: • a - po • bid - prn • c -q • d -qid • h -stat • p -tid

  19. Writing Prescriptions

  20. Format • 3 parts: • Heading • Body • Closing

  21. Heading • Heading • Name*, address*, telephone number of prescriber (DDS) • Name*, address*, age, telephone number of patient • Date of prescription*

  22. Body • Body • The symbol Rx* • Name and dose size or concentration of the drug* • Amount to be dispensed* • Directions to the patient

  23. Closing • Closing • Prescribers signature* (DDS) • DEA number if required (controlled substances) • Refill instructions

  24. Format cont. • NOTE: • * Required by law

  25. Prescriptions from the DDS • Two criteria must be met: • Person for which the prescription is written must be a patient of record • Drug must be for a dental-related condition

  26. Patient Education • Patient should know: • How long and when to take their medication • What precautions to observe • What the medication is for

  27. Clinical Considerations • Keep prescription blanks in a secure place • DEA number should be hand-written only when needed

  28. Let’s Try it!!! • Get your prescription blanks • Write the following prescriptions • Make up any information that is not provided • Make sure you have everything included that is required by law

  29. Write a Prescription for: • Peridex for a 35 year old woman; with 3 refills • Chlorhexidinegluconate 0.12% • Dispense 16 oz. bottle • Rinse with 15 ml for 30 seconds bid after brushing & flossing; expectorate after rinsing

  30. Write a Prescription for: • Sodium fluoride for a 3 year old child - birth date 5/23, 0.5 ppm F in water • Sodium fluoride 0.25 mg • Dispense 30 tablets • 1 tab qd • Do not take with dairy products

  31. Write a Prescription for: • Amoxicillin premedication for a 24 year old man for 2 appointments • Amoxicillin 500 mg • Dispense 8 tablets • Take 4 tabs 1 h before appointment

  32. Chapter 2 Drug Action and Handling

  33. Log Dose Effect Curve

  34. What does it tell us? • How strong or potent a drug is • How well it works • How safe it is

  35. Potency • The amount of drug needed to produce an effect • Relative strength of the drug • Less drug needed = more potent • Determined by the location of the curve on the x-axis • The closer to zero, the more potent the drug

  36. Efficacy • The maximum effect of a drug regardless of dose • Relative effectiveness of the drug • More will not increase effect; may increase likelihood of an adverse reaction • Determined by the height of the curve on the y-axis • “Taller” curves have higher efficacy

  37. Potency vs. Efficacy Example • Hard liquor and beer • Which is more potent? • Which is more effective?

  38. Compare Efficacy & Potency

  39. Look at the previous chart… • Which drug is the most potent? • Which drug has the highest efficacy?

  40. Drug Safety • A log dose curve is also used to determine the: • ED50 • The dose that produces a response in one half of subjects • LD50 • The dose that kills one half of the subjects

  41. Therapeutic Index • These values help to determine the Therapeutic index (TI) or relative safety of a drug • TI= LD50 /ED50 • TI should be greater than 10 for a safe leeway between therapeutic dose and lethal dose

  42. Therapeutic Index

  43. Video- Log Dose Curve • You Tube • http://www.youtube.com/watch?v=UqCEADtuIgc

  44. Mechanism of Action of Drugs • Drugs do not impart a new function to the organism, they either: • Amplify the cell’s function, or • Block it.

  45. Nerve Transmission • Neurotransmitters are released at a synapse causing impulses (nerve action potential) • The neurotransmitter will bind to a receptor interact causing enzyme activation • See figure 2-7 page 15

  46. Nerve Transmission Continued • Enzyme activation causes a channel to open- so that things can enter cell • See Figure 2-6 page 14 • Example: sodium channel • This is how local anesthesia is achieved • Anesthetic blocks depolarization of nerve • Pain message cannot be sent to the brain

  47. Video- Nerve Transmission • You Tube • https://www.youtube.com/watch?v=LT3VKAr4roo

  48. Receptors • Drugs act by forming a chemical bond with specific receptor sites • Lock and key • The better the fit, the better the response • See Figure 2-8 on page 15

  49. Agonist • Agonist • The drug has an affinity for a receptor • Combines with the receptor • Produces an effect

  50. Antagonist • Antagonist - Counteracts the action of the agonist • Three types • Competitive – combines with the same receptor & gives no response. Reduces effect of agonist. • Noncompetitive – uses a different receptor & reduces maximal effect of agonist • Physiologic – uses a different receptor & creates an opposite effect of agonist

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