Pharmacology Review Handout - Drug Effects & Interactions - PDF

Pharmacology Review Handout - [Pharmacological effects and drug interactions] - Knowledge and understanding of pharmacology is essential to safe dental care. This knowledge can: - Serve to **prevent** as well as handle emergency situations - ID **drug interactions** and **adverse eff...

Pharmacology Review Handout - [Pharmacological effects and drug interactions] - Knowledge and understanding of pharmacology is essential to safe dental care. This knowledge can: - Serve to **prevent** as well as handle emergency situations - ID **drug interactions** and **adverse effects** - ID situations in which patient treatment requires **special handling** - [Drug Schedule ] - [Log dose-effect curve] - A graphic representation in which the curve is replotted using the *log of the dose* versus the response - x-axis log of dose (effective or **therapeutic range** is at sharp increase) - Y-axis response to dose (**maximum response** is at plateau) - [Characterization of Drug Action] - [Meperidine and Morphine Comparison] - Both drugs are used to treat severe pain. - Describe the potency of each drug. - Describe the efficacy of each drug. - [Half-Life] - Drug **half-life** (t~1/2~): - The time it takes for the concentration of a drug to "fall" to one-half (50%) of its original blood level; relates to **duration** of the drugs effects - When the half-life is short, the duration of action is short - When the half-life is long, the duration of action is long - [Routes of Administration (ROA)] - The route of administration of a drug affects both the onset and duration of the drug response. - **Onset**: Time it takes for the drug to ***begin*** to have its effect - **Duration**: The ***length*** of time of a drug's effect - [ROA] - **Two major groups** - **Enteral (placed into GI tract)** - Oral - Rectal - **Parenteral (bypasses GI tract)** - Injection (IV, IM, SC/SQ, ID, IT, IP) - Inhalation - Topical (sublingual) - [ROA] - **Oral: *Safest, least expensive, and most convenient ROA*** - First pass effect (or phase I reactions)**\***: - Occurs when orally-admin'd drugs initially pass through the hepatic-portal circulation (liver), which then reduces the amount of drug a available or even inactivate some drugs - **Drugs with a high first-pass effect have a LARGER oral to parenteral dose ratio meaning: they require a LARGER oral dose** - - [ROA] - **Rectal:** Drugs are ***poorly and irregularly absorbed***; Poor patient acceptance; suppositories - **IV: *most rapid response***, best for ER situations, most predictable blood levels; disadvantages include phlebitis, drug irretrievability, and allergy - **IM: *sustained effects***, absorbed due to the high blood flow through skeletal muscles, usually the deltoid region or gluteal mass, massage increases absorption - [ROA] - **Subcutaneous:** Common route to administer ***protein products***, Irritating solutions may cause sterile abscesses or hematoma; insulin and LA - **Intradermal:** injection into epidermis; *TB test*. - **Inhalation:** rapid delivery across large surface area of resp. mucosa; *asthma inhalers, nitrous-oxide sedation* - **Topical:** applied to skin or mucosa, most effective in non-keratinized areas, local effect; *not used on ulcerated, burned or abraded areas* - [ADME] - **Absorption\*:** the transfer of a drug from site of administration to the blood stream - Bypassed in IV ROA - Rate an efficiency depend of ROA - **Lipid soluble drugs** ready cross biological membranes (blood-brain barrier, etc.) - **Distribution:** process by which a drug leaves the blood stream and enters the body system-goes to organ with highest blood flow (**perfusion**) first - Oral-\>liver - Sublingual-\>heart - [ADME] - **Metabolism:** breaking down of drug-usually in **liver**; AKA biotransformation; - *Liver disease or substance abuse may cause impairment* - **Elimination:** removal of drug from body (usually by **renal** excretion) unchanged or as metabolite, terminating drug effects; - Other routes: liver, lungs, bile, GI, sweat, milk, **saliva**, exhalation, & **gingival crevicular fluid** - Ex. Fluoride is eliminates in the urine - [Know Adverse Drug Reactions and Terminology:] - **Toxic reaction**-excessive effect; **dose related** - **Side effect**-undesired effect; **dose-related** - **Idiosyncratic reaction**-abnormal, genetic rel. resp. - **Teratogenic effect** (thalidomide-\>phocomelia) - **Local effects** (tissue necrosis-\>site of LA injection) - **Drug interactions** may result in increased (toxic) or reduced effects - **Allergic reactions** can be mild to life threatening; hypersensitivity reaction; **NOT dose related** - [Autonomic nervous system (ANS]) - **ANS: controls automatic, *involuntary* functions** - BP, heart rate, GI motility, salivation, bronchial/smooth muscle tone. - **It has two divisions:** - **PANS** - **SANS** - [ANS] - **Parasympathetic:** - **Rest and digest -\>Normal** - BP\~vasodilation - HR - blood flow\~digestion - Constricts bronchioles and pupils (**miosis**) - saliva - Pre-ganglionic NT: ACh - Post-ganglionic NT: ACh - **Cholinergic** drugs (parasympathomimetics or muscarinic agents) - **Sympathtic:** - **Fight or flight-\>Reactive** - BP\~vasoconstriction - HR - Dilates bronchioles and pupils (**mydriasis**) - saliva - Pre-ganglionic NT: ACh - Post-ganglionic NT: NE - **Adrenergic** drugs (sympathomimetics) - [Cholinergics (parasympathomimetics)] - Stimulate body functions by direct or indirect action - Indications: - Xerostomia - urinary retention - glaucoma - Examples - Pilocarpine - Nicotine - Contraindications - Asthma - Peptic ulcers - Cardiac disease - GI/Urinary obstruction - [*Anti*cholinergics] - Inhibit body functions by blocking cholinergic (muscarinic) receptors - Examples and indications: - Atropine (decrease salivary flow) - Imodium (diarrhea) - Scopolamine (motion sickness) - Dramamine (motion sickness) - Adverse reactions: - A: anticholinergics - B: blurred vision, bladder retention - C: constipation - D: dry mouth - [Adrenergic drugs (sympathomimetics)] - Stimulate α and β receptors - Indications: Asthma, ADD, vasoconstriction, CNS stimulant, decongestion, anaphylaxis - Examples - Ventolin (albuterol) - epinephrine - Dopamine - Adderall, Ritalin - Adverse effects: CNS (anxiety, fear, tremor, headache), cardiac arrhythmia, hypertension, xerostomia - Contraindications: - angina - uncontrolled hypertension - uncontrolled hyperthyroidism - [Adrenergic-blockers (β blockers)] - Inhibit alpha and beta-1 or beta-2 receptors - Indications: cardiac arrhythmias, hypertension, angina, glaucoma, MI - Examples **("olol"):** - Inderal (propranolol): Non-selective\* beta blocker - Lowers BP by lowering cardiac output - Adverse reactions: bronchoconstriction, arrhythmias, epi in LA - Tenormin (atenolol): Selective beta blocker - Eliminates bronchioconstrictive effect for hypertensive asthmatic patients - Lopressor (metoprolol): Selective beta blocker - Used for hypertension, prevention of MI and angina - Timoptic (timolol): - Used topically to treat glaucoma - [Analgesics ] - Aspirin - Nonopioid, NSAID - MOA: inhibit prostaglandin synthesis - Effects: 4 A's\* - Adverse effects: - Decreased clotting, GI upset, hypersensitivity, Reye's syndrome, Tinnitus - Contraindications: - Blood thinners, gastric ulcers, children - Acetaminophen - Nonopioid - Effects: analgesic, antipyretic - Adverse effects: - Hepatotoxicity and liver necrosis at high doses - Contraindications: - Liver issues - Drug of choice for children, patients on blood thinners, and for POST-OP PAIN following PERIODONTAL DEBRIDMENT because of fewest side effects - [Analgesics ] - Ibuprofen - Nonopioid, NSAID - MOA: inhibit prostaglandin synthesis - Effects: Analgesic, antipyretic, antiinflammatory - Adverse effect: - Decreases clotting, GI issues, drug interactions (ACE inhibitors, aspirin, beta blockers, steroids, loop diuretics) - Contraindications: - Gastric ulcers - Narcotics/Opioids - Block pain receptors in brain w/o loss of consciousness - Effects: analgesic, antitussive, sedation, euphoria - Adverse effects: respiratory depression/sedation, nausea/vomiting, constipation, addiction - Sign of overdose: pinpoint pupils - Examples: morphine, **codeine**, Demerol, Dilaudid, Vicodin - [Antagonists/Addiction] - Narcan (naloxone) - Opioid antagonist - Treat opioid **overdose** - Methadone - Treats narcotic **withdrawal and dependence** - Suppresses need for 24 -36 hours - Only effective in cases of addiction to heroin, morphine, and other opioids - NOT effective with methanphetamines - [Antibiotics/Antiinfectives] - Terms to know: - Bacteriocidal - Bacteriostatic - Minimum Inhibitory Concentration (MIC) - Resistance - Spectrum (Broad and Narrow) - Synergism - Antagonism - [Antibiotics/Antiinfectives] - Penicillin - Most common in dentistry (PenVK) - *Bacteriocidal*-destroys cell wall integrity - Effective against rapid growing - Most likely antibiotic to produce anaphylactic reaction - Most common side effect: rash - Safe in pregnancy - Not effective against penicillinase (beta lactamase) w/o the addition of clavulanic acid (Augmentin) - [Antibiotics/Antiinfectives] - Macrolides - *Bacteriostatic* drugs: Interfere with protein synthesis - Examples: - erythromycin - azithromycin (Zithromax) - clarithromycin (Biaxin) - [Antibiotics/Antiinfectives] - Tetracycline - Broad spectrum - *Bacteriostatic*-protein synthesis - Treats NUG/NUP and Type III (Aggressive Perio) - Inhibits collagenase production - Concentrates in GCF - Not for pregnancy or early childhood - Avoid dairy, antacids, iron - Mixing with other antibiotics results in antagonism - [Antibiotics/Antiinfectives] - Cephalosporin\'s - *Bactericidal*: Inhibits cell wall synthesis - Related to penicillin (10% of those allergic to penicillin are also allergic to cephalosporins) - Examples - cephalexin (Keflex) - cefaclor (Ceclor) - Cefuroxime (Ceftin) - [Antibiotics/Antiinfectives] - Nitromidazoles - *Bactericidal* action: Inhibits nucleic acid synthesis - Effective against obligate anaerobes ONLY - Antabuse-like reaction: avoid alcohol - Think mouthwashes! - Example: metronidazole (Flagyl) - [Antituberculosis Agents] - R: rifampin - I: isoniazid - P: pyraazinamide - E: ethambutol - All 4 (**RIPE**) required to treat TB - If just I or R, intent is prevention - Mantoux Skin Test (PPD) - \+ = exposed not infected - TB spread by droplet aerosol - [Antifungal Agents] - Fungal infections common with antibiotic use or steroid use; also in immunocompromised individuals - Examples; - Nystatin: most frequent; used for topical candidiasis - Fluconazole (diflucan): systemic candidiasis - Mycelex (clotrimazole) - Nizoral (ketoconazole) - [Antiviral Agents] - Herpes - Examples\*: acyclovir (Zovirax), pevalacyclovir (Denavir), valacyclovir (Valtrex) - HIV/AIDS - Examples: Zidovudine (Retrovir, AZT), didanosine (Videz, ddI), zalcitabine (ddC), stavudine (d4T), laminivudine (3TC), and protease inhibitors - [AHA Guidelines for Conditions Requiring Antibiotic Premedication] - Cardiac conditions needing antibiotic premedication: - Prosthetic/artificial heart valve - Previous infective endocarditis - Specific **congenital heart defects**: - Unrepaired cyanotic congenital heart disease - Repaired heart defect with prosthetic patch or device - Cardiac transplantation with cardiac valvular disease - Renal dialysis shunt - Ventriculoatrial hydrocephalic shunt (not stent) - [AHA Guideline Regimen for Antibiotic Premedication]  - [Antianxiety: 2 major classes] - **Barbiturates** **("tal")** - Principle effect: CNS depression - NO analgesic effect! - Ex. - phenobarbital-**most common barbiturate used to treat epilepsy** - Most common side effect is **sedation** - butabarbital - secobarbital - **Benzodiazepines** - **("azepam" or "azolam")** - Useful for short-term treatment of anxiety, insomnia, alcohol withdrawal; muscle relaxant (TMJ disorder), reverse status epilepticus - ALL have sedative properties - NO analgesic or antipsycholotic effects! - Ex. - diazepam (Valium) - lorazepam (Ativan) - alprazolam (Xanax) - [Anticonvulsants] - **Dilantin (phenytoin)** - Depresses CNS to decrease seizures in patients with epilepsy - 50% of patients exhibit gingival hyperplasia - Often used in conjunctoin with phenobarbital - **Phenobarbital (prev. slide)** - **Tegretol** (carbamazepine) - Used to treat partial seizures, trigeminal neuralgia - Does NOT cause gingival hyperplasia - [Antidepressants] - Selective serotonin reuptake inhibitors (SSRI's) - Ex. - fluoxetine (Prozac) - sertraline (Zoloft) - citalopram (Celexa) - escitalopram oxalare (Lexapro) - paroxetine (Paxil) - Monamine oxidase inhibitors (MAO's or MAOI's) - Rarely used today due to fatal interactions with analgesics, SSRI's, and/or certain foods containing tyramine (aged cheese, smoked meats, fish, beer, wine, etc.) - [Antihistamine] - **Benadryl (diphenhydramine)** - Most common - Treats mild allergic reactions - Can be used as a mouthrinse for palliative care - Side effects - Xerostomia - sedation - [Diabetes Agents] - **Insulin** - Used to treat type 1 - Subcutaneous "protein product" - Hypoglycemia is most common side effect - **Oral hypoglycemic drugs** - Used to treat type 2 - metformin (Glucopahge) increases bodies sensitivity to insulin - glyburide (Micronase, Diabeta) stimulates the release of insulin from b-cells in pancreas - [Respiratory Agents ] - Diseases include: asthma, COPD, upper respiratory tract infections - Asthma - SABA (short-acting brochodilators) - albuterol (Ventolin, Proventil), pirbuterol (Maxair) - Provide **immediate** relief of asthma symptoms - LABA (long-acting brochodilators) - Salmeterol (servent) and formoterol (Foradil) - Relive asthma symptoms for longer periods of time - [Respiratory Agents ] - Asthma (cont'd) - Corticosteroids - Used long term to prevent asthma atackds - Examples - beclomethasome dipropioate (QVAR) - fluticasone (Flovent) - triamcinolone acetonide (Azmacort) - flunisolide (Aerobid) - Corticosteroids plus LABA - Advair - [Respiratory Agents ] - COPD - Anticholinergics-first line of treatment - Ipratropium (Atrovent) is drug of choice for long term management - Upper respiratory infection - Nasal decongestants (beta-blockers) - Expectorants - Antitussives-may be opioids or related drugs - [GI Agents] - Treat gastric ulcers or GERD - **Sodium bicarbonate** - Systemic antacid; may be contraindicated in cardiovacular patient due to sodium content - **Proton-pump inhibitors (PPI) "prazole"** - Inhibit gastric secretion - Prilosec (omeprazole) and Prevacid (lansoprazole) - **Histamine blocking agents** "**tidine"** - Block H~2~ histamine receptors which reduces acid secretions - Tagamet (cimetidine) and Pepcid (famotidine) - Should NOT be used with antacids - [Bisphosphonate Drugs] - Used to treat osteoporosis (Fosamax, Boniva) - Also used to treat cancer\~IV infusion - Associated with osteonecrosis of the jaw - Risk remains for years after use - [Prednisone] - Glucocorticosteroid **("sone" and "lone")** - Used in treating autoimmune and inflammatory disorders, Addison\'s disease, and allergic reactions by reducing inflammatory response and suppressing immunity - Increases risk of delayed healing and risk for infection, exacerbates hypotension, may increase blood sugar, osteoporosis with long-term use - May lead to adrenal suppression - Putting patient at risk for adrenal crisis - [Cardiovascular Agents] - **Angina Pectoris** - Nitroglycerin is drug of choice for acute angina - Works as a vasodilator "smooth muscle relaxant" - Administered sublingually - Should be located in emergency kit - **Congestive Heart Failure** - Cardiac glycosides most common drug - Increases strength and force of heart contraction - Ex. - Lanoxin (digoxin) - Digitalis - Dental considerations: caution with vasoconstricting LA, gag reflex, increased salivation - [Cardiovascular Agents] - **Anticoagulant Therapy** - Used to prevent stroke and MI (intravascular clotting) - Risk of gingival hemorrage - Ex. - Coumadin (warfarin)\* - Plavix (clopidogrel) - Prevent clot after MI or stoke or other disorders - Aspirin - Heparin-injection at hospital - **Hypertension (next slides)** - Usually asymptomatic; MOST common of all cardio diseases-affection 60 million in US - Several families of drugs used to treat: - Diuretics - Beta-adrenergic blockers - Calcium channel clockers (CCB's) - Angiotensin Converting Enzyme (ACE) Inhibitors - [Cardiovascular Agents: Hypertension] - **Diuretics (water pills)** 1^st^ - Promoting excretion of Na and H~2~O which decreases blood volume and pressure - 2 **main** types **("ide")**: - Thiazide diuretics: hydrochlorothiazide (HCTZ) is most common - Loop diuretics: furosemide (Lasix) is most common - **Beta-adrenergic blockers or Beta blockers "olol"** 2^nd^ - BP by cardiac output; \*Block beta receptors\~SANS - 2 types: - Non-selective: affects both beta-1 and beta-2 - No asthma or other resp. - propranolol (Inderal) - Selective: affects only beta-1 - atenolol (Tenormin) - metaprolol (Lopressor) - [Cardiovascular Agents: Hypertension] - **CCB's** - BP by causing systemic vasodilation - Not effected by NSAIDs - Common oral effects: gingival enlargement and xerostomia - Ex. - Nifedipine (Procardia, Adalat) - Verapamil (Calan, Isoptin) - Amlodipine (Norvasc) - Diltiazem (Cardizem) - **ACE Inhibitors ("pril")** - Blocks conversion of angiotensin I to angiotensin II (causes vasodilation) - Effect decreased by NSAIDs - Dysgeusia is common - Adverse reactions: hypotension, allergic rxn, dry cough - Ex. - isinopril (Prinivil, Zestril) - captopril (Capoten) - enalapril (Vasotec) - [Drugs of Abuse] - **Cocaine:** - CNS stimulant - Causes vasoconstriction and dilation of pupils - NO epi if used in last 24 hours - **Heroin** - Opioid drug that causes CNS and respiratory depression - Caused sedation and dilated "pinpoint" pupils - **Methamphetamine** - CNS stimulant - NO epi if used in last 24 hours - Associated with severe oral effects - Rampant caries, xerostomia, soda consumption, burned mucosa, "meth mouth" - Males, 19-40 most common - [Emergency Drugs] - [Miscellaneous hints ] - Statins: lower cholesterol - Lipitor (atorvastatin) - Lescol (fluvastatin) - Mevacor (lovastatin) - Zocor (simvastatin) - Crestor (rosuvastatin) - Thyroid - Hypothyroidism: levoxythyroxine (Synthroid) - Iodine deficiency=goiter - [Miscellaneous hints ] - Pupil dilation: sign of opioid overdose, cocaine use - Alcohol + nitroglycerin = hypotension - Estrogen - Steroid hormone most frequently used for contraception, post-menopausal therapy, menstrual disturbances - Estradiol most potent estrogen produced - May promote: endometrial carcinoma and breast cancer, increase gingival inflammation - Ex: Estraderm, Premarin - [Miscellaneous hints ] - 3 drugs that commonly cause gingival overgrowth: - Phenytoin (Dilantin) - CCBs such as nifedipine - Cyclosporins - Cardiac dose of epinephrine containing LA is 2 carpules. - [Rx Abbreviations] - ac: before meals - d: day - h: hour - po: by mouth - hs: at bedtime - pc: after meals - prn: as needed - sig: label - tab: tablet - stat: immediately - bid: twice per day - tid: three times per day - qid: four times per day - qd: every day - gt: drop - ud: as directed - [General Anesthetics\*] - Potent CNS depressants - Produce reversible loss of consciousness and insensitivity to pain stimulus - Stages and Planes: - Stage 1: analgesia - reduced pain sensation - Conscious and responsive - Respiration and reflexes are regular - Nitrous oxide - End of stage marked by loss of consciousness - Stage 2: delirium/excitement - Begins with unconsciousness - Associated with involuntary movement and excitement - Stage 3: surgical anesthesia - Stage where major surgery in completed - Stage 4: resp. or medullary paralysis - Complete cessation of all respiration - If not reversed immediately, death occurs