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RT 210 Pharmacology

RT 210 Pharmacology. Terminology. Drug Exerts biological effect used for Treatment Diagnosis Prevention Chemical name Chemical structure of the drug. Terminology. Generic name Name given by US Pharmacopoeia Trade name Brand or patented name Side effect: Other than desired effects

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RT 210 Pharmacology

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  1. RT 210 Pharmacology

  2. Terminology • Drug • Exerts biological effect used for • Treatment • Diagnosis • Prevention • Chemical name • Chemical structure of the drug

  3. Terminology • Generic name • Name given by US Pharmacopoeia • Trade name • Brand or patented name • Side effect: Other than desired effects • Half life: Length of time when 1/2 dosage is still active in the body

  4. Terminology • Tolerance: A condition in which the dose of a drug must be increased (over time) to obtain the desired effect -or- a decreasing intensity of responsiveness to a drug over time • Tachyphylaxis: Rapidly developing tolerance to a drug -or- a rapid decrease in responsiveness to a drug. • Additive effects: The effect of two chemicals acting simultaneously on the same receptors & is the simple sum of the effects that they would have if acting alone

  5. Terminology • Synergism: The presence of one chemical that enhances the effects of the second. Also, when 2 drugs act on a target organ by different mechanisms of action & the effect of the pair is greater than the sum of the separate effects of the drugs.

  6. Terminology Potentiation: Special case of synergism in which one drug has no effect, but can increase the activity of the other drug. Also, the action of these two drugs result in the total effect being greater than the sum of the independent effects.

  7. Terminology • Pharmaceutical phase: Method by which a drug is delivered • Inhalation (Benefits) • Immediate onset of action at desired site • Reduced systemic side effects • Smaller doses required • Ability of patient to self administer • Pharmacokinetic phase: Time required for drug absorption, distribution, metabolization, and excretion

  8. Terminology • Pharmacodynamic phase: Mechanism of action by which a drug causes its therapeutic effect • Agonist: A substance that binds to a receptor and triggers a response in the cell • Antagonist: A substance that binds to a receptor but fails to activate the receptor and actually blocks it from activation by agonists

  9. Prescription requirements • Patient name • Drug name • Dose • Frequency • Route of administration

  10. Check before administering drug • Chart for information • Patient's name band • Medication label • Dates of expiration or opening of the drug • Dosage • Response to previous administration of drug

  11. Normal routes of administration (fastest to slowest) • IV (intravenous) • Inhaled (aerosol to lung) • IM (intramuscular) • Sub Q (subcutaneous injection) • Sublingual or rectal absorption • Oral • Topical

  12. Concentration • The concentration is the percent solution of the active ingredient in the drug • It is the weight (in grams or mg) of solute dissolved in a volume (in ml) of solvent expressed as a percentage • 1% solution means that 1 gram (1000mg) of solute is dissolved in 100 ml of solvent • 1000 mg/100 ml = 10 mg/ml

  13. It is possible to determine the amount of solute or solvent needed in a solution of a known percentage • Before you can determine the amount of solute or solvent that is needed you must first express the concentration as mg/ml • Multiply the percentage by 10 • i.e. 1% * 10 = 10 mg/ml • 0.5% * 10 = 5 mg/ml

  14. Determine what you are trying to find • Solute (mg) = solvent (ml) * concentration (mg/ml) • You have 1 ml of a 1% solution. How much solute do you need? • 1% * 10 = 10 mg/ml • Y mg = 1 ml * 10 mg/ml • Y mg = 10 mg • Solvent (ml) = solute (mg) ÷ concentration (mg/ml) • You have 5 mg of a 1% solution. How much solvent do you need? • 1% * 10 = 10 mg/ml • Y ml = 5 mg ÷ 10 mg/ml • Y ml = 0.5 ml

  15. Ratios • Drug solutions may be expressed as a ratio instead of a percentage • A 1:100 solution is a 1% solution and a 1:200 solution is a 0.5 % solution • This is derived by the following equation for a 1:100 solution • 1/100 = 0.01 then multiply by 100 to give a percentage Thus 0.01 * 100 = 1% • For a 1:200 solution we do the same thing • 1/200 = 0.005 then we multiply that by 100 Thus 0.005 * 100 = 0.5%

  16. Ratios • We can determine the desired solute or solvent with a simple equation • Solution • 10 ml of a 1:100 solution. How much solute do we need? • Convert the 1:100 ratio into grams per ml • Take 1 and multiply it by 1000 to give us 1000 mg • Add ml to 100 so now we have 1000 mg/100 ml

  17. Ratios

  18. Solvent • 10 mg of a 1:200 solution. How much solution do we need? • Set up the equation as before

  19. Nervous system • Sympathetic nervous system • Adrenergic • Uses epinephrine as a neurotransmitter • Fight or flight • Dilates pupils • Dilates bronchioles • Speeds up heart rate • Secretes adrenaline

  20. Nervous system • Parasympathetic nervous system • Cholinergic • Uses acetylcholine as a neurotransmitter • Feed or breed • Constricts pupils • Constricts bronchioles • Slows down heart rate

  21. Nervous system • Adrenergic stimulation • Three adrenergic receptors • Alpha: Vasoconstriction • Beta 1: Increased cardiac rate and strength of contraction • Beta 2: Bronchodilation

  22. Nervous system • Adrenergic stimulation (cont) • Stimulation of receptors with sympathomimetic drugs causes • Activation of adenylate cyclase • Increase conversion of atp into cyclic 3'5'amp • Results in bronchodilation

  23. Nervous system • Adrenergic stimulation (cont) • Post stimulation • Phosphodiesterase converts cyclic 3'5'amp into 5'amp • Break down of cyclic 3'5'amp ends bronchodilation

  24. Cholinergic stimulation • Nicotinic receptors • Stimulation affects all of the PNS and also affects the sympathetic nervous system and skeletal muscles • Causes paralysis of skeletal muscles • Increases production of dopamine (pleasure response) • Muscarinic receptors :Stimulation of receptors stimulates only the PNS

  25. Specific sympathomimetics • Isoproterenol HCl • Trade name – Isuprel • Generic ‑ Isoproterenol HCl • Concentration ‑ 1:200 (0.5%) solution • Receptor effects • Alpha 0 • Beta1 4+ • Beta 2 4+ • Short duration • Dosage: 0.25‑0.5 ml QID or q 4 hours

  26. Specific sympathomimetics • Isoetharine • Trade name: Bronkosol • Generic – Isoetharine • Concentration – 1:100 (1%) solution • Effects • Alpha 0 • Beta1 1+ • Beta2 3+ • Duration – medium

  27. Specific sympathomimetics • Isoetharine (cont) • Dosage • 0.25-0.5ml QID • 1cc maximum

  28. Specific sympathomimetics • Metaproterenol sulfate • Trade • Alupent • Metaprel • Generic ‑ Metaproterenol sulfate • Concentration – 5% solution • Effects • Alpha – 0 • Beta1 ‑ 2+ • Beta2 ‑ 2+ • Medium duration (2 – 4 hrs) • Dosage • 0.2 ‑ 0.3 ml tid, qid • Maximum dose is 0.3 ml

  29. Specific sympathomimetics • Racemic epinephrine • Trade name • Vaponephrine • Micronephrine • Asthmanephrine • Generic ‑ Racemic epinephrine • Concentration - 2.25% • Receptor effects • Alpha 2+ • Beta1 3+ • Beta2 2+ • Duration of 0.5 ‑ 2 hours • Dosage: 0.25 - 0.5 ml q1-2 hours

  30. Specific sympathomimetics • Epinephrine HCl • Trade – Adrenalin • Generic • Epinephrine HCl • Receptor effects • Alpha ‑ 3+ • Beta1 ‑ 4+ • Beta2 ‑ 3+ • Concentration - 1:100 (1%) solution • Short duration • Dosage: 0.2 – 0.5 ml q2-4 hours

  31. Specific sympathomimetics • Salbutamol, Albuterol • Trade name • Ventolin • Proventil • Generic name • International – salbutamol • US – albuterol • Receptor effects • Alpha – 0 • Beta1 ‑ 1+ • Beta2 ‑ 4+ • Concentration - 1:200 (0.5%) solution • Long duration • Dosage • MDI 2 puffs TID, QID • 0.5 ml TID, QID

  32. Specific sympathomimetics • Terbutaline sulfate • Trade name • Bricanyl • Brethine • Generic name ‑ terbutaline sulfate • Receptor effect • Alpha – 0 • Beta1 ‑ 1+ • Beta2 ‑ 3+ • Concentration - 200 µg/puff • Long duration • Dosage: 2 puffs q4-6 hours

  33. Specific sympathomimetics • Levalbuterol • Trade name: Xopenex • (R)-Isomer of Albuterol • Very specific Beta2 agonist • Same Beta2 as Albuterol • No Alpha effects and almost no Beta1 effects • Dosage • 0.63 mg every 6 to 8 hours • 1.25 mg TID • Long duration

  34. Specific sympathomimetics • Side effects of adrenergic bronchodilators • Palpitations • Tachycardia • Hypertension • Restlessness • Fear • Anxiety • Tremor • Weakness • Dizziness • Pallor

  35. Xanthines • Inhibits phosphodiesterase thus maintaining levels of cyclic 3'5'amp • This results in better bronchodilation • Types • Theophylline: Available in tablet and elixir form • Aminophylline • Administered IV or in tablet form • After a loading dose, serum levels are monitored • Therapeutic serum level of 10‑20 mg/dl

  36. Xanthines • Side effects • Dizziness • Headache • Restlessness • Palpitations, tachycardia • Nausea, vomiting • Anorexia

  37. Xanthines • Many physicians now disregard this agent as a choice to treat asthma routinely • Has found favor in treating acute asthma attacks with hospital admittance • Subcutaneous Epinephrine is often favored as the first agent to try in Status Asthmaticus

  38. Parasympatholytics/anticholinergic • Enhance sympathetic effects • Atrovent • Ipratropium bromide • Contraindications • Allergy to soybeans and peanuts • Blocks production of cGMP • Side effect: occasional dry mouth • Often used in conjunction with albuterol to enhance bronchodilation

  39. Parasympatholytics/anticholinergic • Atropine • Atropine sulfate • Frequently used in surgery • Blocks production of cGMP • Contraindications • Sensitivity • Glaucoma • Tachycardia

  40. Parasympatholytics/anticholinergic • Atropine (cont) • Side effects • Dilated pupils • Thick drying of secretions • Dry mouth • Palpitations • Tachycardia

  41. Corticosteroids • Used in the management of the inflammatory process associated with asthma, reactive airway disease, and other pulmonary disorders • Administered orally or aerosolized

  42. Corticosteroids • Side effects • Inhaled • Oral candidiasis • Throat irritation • Dry mouth • Systemic • Cushing’s syndrome • Immunosuppression • Diabetes

  43. Corticosteroids • Aerosolized steroids • Dexamethasone • Decadron • MDI provides 84 µg per inhalation • Dosage • 3 to 4 puffs 3 to 4 times a day • Not to exceed 12 puffs per day

  44. Corticosteroids • Aerosolized steroids (cont) • Beclomethasone diproprionate • Vanceril, beclovent • MDI provides 42 µg per inhalation • Dosage • 2 puffs 3 to 4 times a day • Not to exceed 12 puffs per day

  45. Corticosteroids • Aerosolized steroids (cont) • Flunisolide • Aerobid • MDI provides 250µg per inhalation • Dosage • 2 puffs 2 times a day • Not to exceed 4 puffs per day

  46. Corticosteroids • Aerosolized steroids (cont) • Triamcinoloneacetonide • Azmacort, • MDI provides 100 µg per inhalation • Dosage • 2 puffs 3 to 4 times a day • Not to exceed 12 puffs per day • Budesonide - Pulmicort Respules - 0.25 mg/2 ml , 0.5 mg/2 ml Turbuhaler – (DPI) 1-2 inhalations twice daily

  47. Corticosteroids • Aerosolized steroids (cont) • Fluticasone propionate • Flovent • MDI provides 44, 110, or 220 µg per inhalation • Dosage • 2 puffs of 44 µg 2 times a day for mild asthma • 4 puffs of 220 µg 2 times a day for severe asthma

  48. Corticosteroids • Oral steroids • Prednisone • Action • Reduce inflammation • Potentiation of sympathomimetics • Dosage • Loading dose of 4 mg per kg of body weight • Maintenance dose of 1 mg per kg • Therapeutic serum levels: 100 to 150 mcg/100ml • May be given for a 2-3 week period or long term • To manage the patient’s condition more adequately

  49. Long acting bronchodilators • Salmeterol xinafoate • Serevent • DPI provides 50 µg per blister • 1 blister BID • MDI provides 25 µg per puff • 2 puffs BID • 12 hour duration • 20-60 minute onset • Maintenance therapy only – not for emergency

  50. Long acting bronchodilators • Formoterol • Foradil • Dpi provides 12 µg per puff • 1 puff bid • 12 hour duration • 15 minute onset • Even though rapid onset and peak effect, better maintenance drug than rescue agent

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