Dental Pharmacology Essentials

• Pharmacology knowledge is crucial for safe dental care, preventing emergencies, recognizing drug interactions, and managing patients needing special care.

Drug Schedule

• Schedule I drugs have no accepted medical use and a high abuse potential; examples include heroin and LSD.
• Schedule II drugs require a written prescription with a signature and have no phoned-in refills; examples include morphine, oxycontin, hydrocodone and fentanyl.
• Schedule III drugs require a phoned-in prescription with no more than 5 refills in 6 months; examples include Tylenol w/ codeine, anabolic steroids, and testosterone.
• Schedule IV drugs are the same as Schedule III drugs, examples include Valium and Darvon
• Schedule V drugs may be OTC (over the counter), examples include codeine-containing cough meds.

Log Dose-Effect Curve

• A log dose-effect curve is a graphical representation of the log of the dose versus the response.
• X-axis represents the log of the dose, indicating the effective or therapeutic range at a sharp increase.
• Y-axis represents the response to the dose, with the maximum response shown as a plateau.

Meperidine and Morphine Comparison

• Both meperidine and morphine are used to treat severe pain.
• Potency and efficacy differ between the two drugs.

Half-Life

• Drug half-life is the time it takes for a drug's blood concentration to fall to one-half of its original level, which relates to the drug's duration of effects.
• Short half-life means a short duration of action.
• Long half-life means a long duration of action.

Routes of Administration (ROA)

• ROA affects both the onset and duration of a drug's effect.
• Onset is the time it takes for the drug to start having an effect.
• Duration is the length of time a drug's effect lasts.
• Two major groups of ROA are enteral (placed into the GI tract) and parenteral (bypasses the GI tract).
• Enteral routes include oral and rectal.
• Parenteral routes include injections (IV, IM, SC/SQ, ID, IT, IP), inhalation, and topical (sublingual).
• Oral ROA is the safest, least expensive, and most convenient.
• Drugs administered orally initially pass through the hepatic-portal circulation (liver), reducing the amount of available drug or inactivating some drugs.
• Drugs with a high first-pass effect require a larger oral dose.

ROA Details

• Rectal drugs are poorly and irregularly absorbed; comes in suppository form.
• IV provides the most rapid response and predictable blood levels; disadvantages are phlebitis, drug irretrievability, and allergy.
• IM provides sustained effects due to absorption by the high blood flow in skeletal muscles and massage increases absorption.
• Subcutaneous is a common route for protein products and irritating solutions may cause sterile abscesses or hematoma; examples are insulin and LA.
• Intradermal involves injection into the epidermis like with a TB test.
• Inhalation provides rapid delivery across a large surface area of respiratory mucosa; examples are asthma inhalers and nitrous-oxide sedation.
• Topical application is most effective in non-keratinized areas and is not used on ulcerated, burned, or abraded areas; produces a local effect.

ADME

• Absorption is the transfer of a drug from the site of administration to the bloodstream and is bypassed in IV.
• Rate and efficiency of ROA depends on absorption.
• Lipid-soluble drugs easily cross biological membranes (blood-brain barrier, etc.).
• Distribution is the process where a drug leaves the bloodstream and enters the body, going first to the organ with the highest perfusion.
• Oral distribution goes to the liver first.
• Sublingual distribution goes to the heart first.
• Metabolism involves breaking down drugs, usually in the liver and is also known as biotransformation.
• Liver disease or substance abuse can cause impairment.
• Elimination is the removal of a drug from the body, usually via renal excretion, terminating its effects; can also occur through the liver, lungs, bile, GI, sweat, milk, saliva, exhalation, and gingival crevicular fluid.
• Fluoride is eliminated in the urine.

Adverse Drug Reactions

• Toxic Reaction: excessive effect that is dose-related.
• Side Effect: undesired effect and dose-related.
• Idiosyncratic Reaction: Abnormal, genetic response.
• Teratogenic Effect: can cause congenital abnormalities (thalidomide->phocomelia).
• Local Effects: include tissue necrosis at the site of LA injection.
• Drug Interactions: May cause increased (toxic) or reduced effects
• Allergic Reactions: can range from mild to life-threatening hypersensitivity and is not dose related.

Autonomic Nervous System (ANS)

• ANS controls automatic, involuntary functions such as BP, heart rate, GI motility, salivation, and bronchial/smooth muscle tone.
• The two divisions of the ANS are PANS and SANS.

ANS: Parasympathetic

• Parasympathetic: controls "rest and digest" functions and returns body to normal.
• Decreases blood pressure via vasodilation.
• Decreases Heart Rate.
• Increases blood flow to digestion.
• Constricts bronchioles and pupils (miosis)
• Increases Saliva
• Pre-ganglionic neurotransmitter: ACh
• Post-ganglionic neurotransmitter: ACh
• Cholinergic drugs (parasympathomimetics or muscarinic agents)

ANS: Sympathetic

• Sympathetic: controls "fight or flight" response.
• Increases Blood Pressure via vasoconstriction
• Increases Heart Rate
• Dilates bronchioles and pupils (mydriasis)
• Decreases Saliva
• Pre-ganglionic neurotransmitter: ACh
• Post-ganglionic neurotransmitter: NE
• Adrenergic drugs (sympathomimetics)

Cholinergics

• 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

Anticholinergics

• Anticholinergics: Inhibit body functions by blocking cholinergic (muscarinic) receptors.
• Examples & Indications: Atropine (decrease salivary flow), Imodium (diarrhea), Scopolamine/Dramamine (motion sickness).
• Adverse Reactions: Anticholinergic effects, Blurred Vision, Bladder Retention, Constipation, Dry Mouth.

Adrenergic Drugs

• 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

• Adrenergic-blockers (β blockers): Inhibit alpha, beta-1, or beta-2 receptors.
• Indications: Cardiac arrhythmias, hypertension, angina, glaucoma, MI.
• Examples ("olol"): Inderal (propranolol): Non-selective* beta blocker that lowers BP by lowering cardiac output.
• Adverse reactions: Bronchoconstriction, arrhythmias, epi in LA.
• Tenormin (atenolol): Selective beta blocker that eliminates bronchioconstrictive effect for hypertensive asthmatic patients.
• Lopressor (metoprolol): Selective beta blocker that is used for hypertension, prevention of MI and angina.
• Timoptic (timolol): Used topically to treat glaucoma.

Analgesics: Aspirin

• Aspirin: Nonopioid, NSAID.
• MOA: Inhibits prostaglandin synthesis
• Effects: 4 A's* and has adverse effects.
• Adverse Effects: Decreased clotting, GI upset, hypersensitivity, Reye's syndrome, Tinnitus
• Contraindications: Blood thinners, gastric ulcers, children.

Analgesics: Acetaminophen and Ibruprofen

• Acetaminophen: Nonopioid; effects are analgesic and antipyretic.
• Adverse effects: Hepatotoxicity and liver necrosis at high doses
• Contraindications: Liver issues
• Best drug choice for children, patients on blood thinners, and post-op pain following periodontal debridement.
• Ibuprofen: Nonopioid, NSAID; inhibits prostaglandin synthesis and has analgesic, antipyretic, and anti-inflammatory effects.
• Decreases clotting, GI issues, drug interactions (ACE inhibitors, aspirin, beta blockers, steroids, loop diuretics).
• Contraindications: Gastric ulcers.

Narcotics/Opioids

• Block pain receptors in the brain without loss of consciousness; analgesic, antitussive, sedation, euphoria.
• Adverse effects include respiratory depression/sedation, nausea/vomiting, constipation, and addiction.
• Pinpoint pupils are a sign of overdose.
• Examples of drugs are morphine, codeine, Demerol, Dilaudid, and Vicodin.
• Antagonists/Addiction
• Narcan (naloxone): Opioid antagonist used to treat opioid overdose.
• Methadone: Treats narcotic withdrawal and dependence.
• Suppresses the need for narcotics for 24-36 hours.
• Effective in cases of addiction to heroin, morphine, and other opioids but NOT methamphetamines.

Antibiotics/Antiinfectives

• Bactericidal: Kills bacteria.
• Bacteriostatic: Inhibits bacterial growth.
• Minimum Inhibitory Concentration (MIC): Lowest concentration of a drug that inhibits the visible growth of a microorganism after overnight incubation.
• Resistance: Ability of an organism to withstand the effects of an antimicrobial agent.
• Synergism: Interaction of two or more medicines that results in a greater effect than when the medicines are taken alone.
• Antagonism: Combination of two or more drugs that results in less effect.
• Spectrum (Broad and Narrow): Range of activity of a drug.
• Penicillin: Most common in dentistry (PenVK); bacteriocidal and destroys cell wall integrity.
• Effective against rapidly growing bacteria and is the most likely antibiotic to produce an anaphylactic reaction.
• Most common side effect is rash and is safe in pregnancy.
• Not effective against penicillinase (beta lactamase) without the addition of clavulanic acid (Augmentin).
• Macrolides: Bacteriostatic and interfere with protein synthesis.
• Examples: Erythromycin, azithromycin (Zithromax), and clarithromycin (Biaxin).
• Tetracycline: Broad spectrum, bacteriostatic, and inhibits protein synthesis.
• Treats NUG/NUP and Type III (Aggressive Perio). Inhibits collagenase production and concentrates in GCF.
• Not for pregnancy or early childhood; avoid dairy, antacids, and iron.
• Mixing with other antibiotics results in antagonism.
• Cephalosporin's: Bactericidal and inhibits cell wall synthesis.
• Related to penicillin, and has a 10% cross-allergy rate.
• Examples: Cephalexin (Keflex), cefaclor (Ceclor), and cefuroxime (Ceftin).
• Nitromidazoles: Bactericidal and inhibits nucleic acid synthesis.
• Effective against obligate anaerobes ONLY and has an Antabuse-like reaction so it is important to avoid alcohol.
• Example: Metronidazole (Flagyl).
• Antituberculosis Agents; Includes R: rifampin, I: isoniazid, P: pyraazinamide, and E: ethambutol.
• All 4: RIPE is required to treat TB and if only I or R is given, the intent is prevention.
• Mantoux Skin Test (PPD)+: means it will be exposed but not infected.
• TB spread by droplet aerosol

Antifungal and Antiviral Agents

• Antifungal: used for fungal infections common with antibiotic or steroid use, can also be used for immunocompromised individuals.
• Examples: Nystatin: most frequent; used for topical candidiasis.
• Fluconazole (diflucan): systemic candidiasis.
• Mycelex (clotrimazole). Nizoral (ketoconazole).
• Antiviral Agents: used for Herpes
• Examples*: acyclovir (Zovirax), pevalacyclovir (Denavir), valacyclovir (Valtrex)
• HIV/AIDS: Examples: Zidovudine (Retrovir, AZT), didanosine (Videz, ddl), zalcitabine (ddC), stavudine (d4T), laminivudine (3TC), and protease inhibitors.

AHA Guidelines and Antianxiety Agents

• Cardiac conditions needing antibiotic premedication: Prosthetic/artificial heart valve, Previous infective endocarditis, unrepaired cyanotic congenital heart disease, Repaired heart defect with prosthetic patch or device, Cardiac transplantation with cardiac valvular disease, Renal dialysis shunt, and Ventriculoatrial hydrocephalic shunt (not stent).
• Antianxiety Agents: There are 2 major classes: barbiturates and benzodiazepines.
• Barbiturates (“tal"): Principle effect: CNS depression; NO analgesic effect!.
• Example: 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 and do NOT have analgesic or antipsycholotic effects!.
• Examples: 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.

Other Medications

• Antidepressants: Selective serotonin reuptake inhibitors (SSRI's): 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
• Asthma (cont'd)
• Corticosteroids: Used long term to prevent asthma atackads
• Examples: beclomethasome dipropioate (QVAR) fluticasone (Flovent) triamcinolone acetonide (Azmacort) flunisolide (Aerobid) Corticosteroids plus LABA: Advair
• 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 and Cardiovascular Agents

• GI Agents: Treat gastric ulcers or GERD Sodium bicarbonate: Systemic antacid; may be contraindicated in cardiovascular patient due to sodium content
• Proton-pump inhibitors (PPI) “prazole”: Inhibit gastric secretion Prilosec (omeprazole) and Prevacid (lansoprazole)
• Histamine blocking agents “tidine”: Block H2 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

Additional Agents

• 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.
• Atherosclorosis: Lescol (fluvastatin), Mevacor (lovastatin), Zocor (simvastatin), or Crestor (rosuvastatin)
• Thyroid: Hypothyroidism: levoxythyroxine (Synthroid), lodine 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, Ex: Estraderm, Premarin.
• GI Agents: Treat gastric ulcers or GERD; Sodium bicarbonate (Systemic antacid; may be contraindicated in cardio patients), Prilosec, Tagamet
• Miscellaneious hints: 3 drugs that commonly cause gingival overgrowth: Phenytoin, CCBs such as nifedipine, Cyclosporins
• Cardiac dose of epinephrine containing LA is 2 carpules

Antibiotics

• Cardiovascual Agents:
• Anticoagulant Therapy: Used to prevent stroke and MI (intravascular clotting). Risk of gingival Hemorrage. Ex: Coumadin(warfarin) and Plavix (clopidogrel), Aspirin, Heparin-injection at hospital.
• Hypertension (next slides): Usually asymptomatic MOST common of all cardio diseases of 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.
• Diuretics promote excretion of Na and H2O, which decreases blood volume and pressure. 2 main types.
• Thiazide diuretics. hydrochlorothiazide (HCTZ) is most common. Loop diuretics. furosemide(Lasix) is most common
• Beta-adrenergic blockers or Beta blockers decrease BP because it inhibits by cardiac output. Block beta receptors-SANS. (2) Types
• Non-selective affects both beta-1 and beta-2. propranolol (Inderal)
• Selective. affect only beta-1. atenolol(Tenormin). metaprolol (Lopressor).
• Ca channel Blockers decreases BP by causing systemic vasodilation. gingival enlargement and xerostomia

Additional Hypertension, Drugs of Abuse

• ACE Inhibitors (“pril”): blocks conversion of angiotensin 1 to angiotensin II .decreases by NSAIDs. Adverse reactions is hypotension, allergic rxn, dry cough Ex: Lisinopril or captopril or enalapril
• Drugs of Abuse: Cocaine: CNS stimulant. causes vasoconstriction; NO epi if used in last 24 hours Heroin: opioid that causes CNS sedative. causes dilation pupils Methamphetamine: associated with severe oral effecst;
• Rampant caries and xerostomia.

Emergency Drugs

• Miscellaneous hints: Statins: lower cholesterol
• The cardiac dose of epinephrine containing LA is 2 carpules. Pupil dilation is a sign of overdose or cocaine use. Alcohol plus nytroglycerin equal hypotention.
• Emergency drugs that may be used are:
  • Epinephrine - to treat anaphylaxis/ severe alleric rxn
  • Diphenhydramine - to teat mild to moderate allergic rxn
  • Hydrocortisone - to treat an adreanal crisis
  • Albuterol - to treat asthma, or respective diseases
  • Oral carbohydrate/glucose - used to treat diabetes, or hypoglycemia
  • Diazepam (Valium) - used for management of seizure
  • Naloxone (Narcan) - used for opioid overdose
  • Oxygen - used for most emergency situations except hyperventilation and COPD

Antibiotic Drugs

• Cardiovascular Drugs - antihypertensives: ACE inhibitors, beta blockers
• Drugs used to treat cardiac arrhythmia are "olol"
• Drugs used to treat partial seizures or trigeminal neuralgia - Dilantin, phenobarbital
• Drugs that stimulate saliva - pilocarpine
• Drugs that decrease saliva - Atropine