Ar medical conditions and dental care-dental toxicology

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Ar medical conditions and dental care-dental toxicology

  1. 1. Identify Medical Conditions Necessitating The Drug And Its Potential Impact On The Provision Of Dental Care د . اياد أبو ربيع
  2. 2. Drug And Its Potential Impact On The Dental Care <ul><li>When a patient presents with a lengthy medication list, a primary concern is whether or not there are medications on the list that may be required in the event of an emergency.  The patient’s drugs should be categorized to identify immediate safety considerations </li></ul><ul><li>Does the patient require nitroglycerin for anginaor an inhaler for dyspnea?  If so, these drugs should be available during the dental appointment. </li></ul>
  3. 3. Important consideration <ul><li>  Secondly, do any of the drugs on the list have the potential to complicate dental treatment?  For example, is the patient taking the anti-coagulant Warfarin?  If so, has the patient’s physician been alerted to the pending dental treatment and have all the necessary lab tests been run and the results available? </li></ul><ul><li>Has the patient taken their dose of insulin but not eaten, placing them at risk for hypoglycemia? </li></ul>
  4. 4. Important consideration <ul><li>  </li></ul><ul><li>Third, could any of the medications compromise our treatment outcomes?  For example, is the healing time or risk of infection increased because the patient is on immunosuppressants such as Prednisone or chemotherapeutics such as Vincristine or Methotrexate? </li></ul>
  5. 5. Potential drug related oral health/management complications.   Delayed healing, mucositis, fungal infections  Vincristine Chemotherapeutic agents   Increase risk of bacterial and fungal infection, poor stress response  Corticosteroids* Immunosuppressants for organ transplants* Immunosuppressants Excessive bleeding Aspirin, Warfarin* Anticoagulants Management Problems Example Drugs Drug Groups
  6. 6. Potential drug related oral health/management complications. Delayed bone healing, bone necrosis Pamidronate (Aredia) Alendronate (Fosmax) Bisphosphonate bone stabilizers Hypoglycemia Insulin*, sulfonylureas Hypoglycemics   Respiratory suppression, fall risk  Tylenol, Valium, Demerol Sedative hypnotics*, narcotics, barbiturates Management Problems Example Drugs Drug Groups
  7. 7. Natural products that may alter dental management <ul><li>Many natural products can have a physiologic impact that requires altered dental management, so the clinician should be sure to inquire if the patient is taking any natural products </li></ul>
  8. 8. Natural products that may alter dental management These herbs inhibit liver enzymes so they may potentiate the liver enzyme (cytochrome P450) inhibiting the effect of erythromycin and ketokonazole. Echinacea St. John’s Wort May increase bleeding Feverfew Garlic , Ginger Ginko Biloba Bilberry Dong Quai St. John’s Wort Possible Dentally Relevant Problem Compound
  9. 9. Natural products that may alter dental management May potentiate the effects of sedative Hypnotics and anti-anxiety drugs Valerian Hepatotoxicity, especially in those taking other medications metabolized in the liver. Sedative effects. Kava-Kava May increase blood pressure and heart rate due to anxiety or if epinephrine/vasoconstrictor used. Ephedra (Ma-Huang) Bitter orange Possible Dentally Relevant Problem Compound
  10. 10. Create A System For Prescribing <ul><li>Reviewing with the patient the indications for all medications on the list allows the dentist the opportunity to clarify the health history and provides important information about the patient and any potential risks or management issues to be considered when treating the patient. </li></ul>
  11. 11. Create A System For Prescribing <ul><li>  In some cases the patient will not be able to effectively communicate their health issues, in which case their medication list may be the dental clinician’s only immediate resource for identifying medical problems which are so severe they require pharmacologic intervention. </li></ul><ul><li>For instance, a patient may not report they have hypertension, but their medication list may include Furosemide, a diuretic.  Both the hypertension and the diuretic can have implications on the provision of dental care as well as direct and indirect effects on the patient’s oral health. </li></ul>
  12. 12. Create A System For Prescribing <ul><li>After carefully reviewing the existing medications to assess the patient’s systemic condition and considering the potential effects of the medication on oral health </li></ul><ul><li>the next consideration relates to drugs administered or prescribed for the patient by the dentist </li></ul>
  13. 13. Create A System For Prescribing <ul><li>The first consideration is “are there any absolute contraindications to the medication that will be prescribed,” such as a drug allergy?   </li></ul><ul><li>Does the drug have the potential to exacerbate any of the patient’s medical conditions (i.e., drug-physiology interaction), such as NSAIDs increasing the risk of gastrointestinal bleeding in a patient with gastric ulcers?  </li></ul>
  14. 14. Create A System For Prescribing <ul><li>Does the drug have the potential to interact with any of the over-the-counter, herbal supplements or medications reportedly taken by the patient such as erythromycin, inhibiting liver enzymes and decreasing the metabolism of the anti-coagulant Coumadin? </li></ul><ul><li>  Patients taking are at high risk of developing drug-drug interactions. some of these drugs are highly titrated and a small change in their blood levels can have a large physiological impact. </li></ul>
  15. 15. وصف الأدوية لمريض يتناول أدوية معينة <ul><li>Four drugs commonly used in dentistry, inhibit cytochrome P450 enzymes </li></ul><ul><ul><li>Erythromycin </li></ul></ul><ul><ul><li>Clarithromycin </li></ul></ul><ul><ul><li>Metronidazole </li></ul></ul><ul><ul><li>ketoconazole,.   </li></ul></ul>
  16. 16. Create A System For Prescribing <ul><li>The P450 enzymes enzymes are responsible for metabolizing many drugs.  Their inhibition of drugs used in dentistry can significantly decrease the rate of drug metabolism.   </li></ul><ul><li>Erythromycin and ketoconazole have the greatest potential to cause such inhibition.  So, to avoid the risk of such drug-drug interactions, do not use these drugs in patients already taking other drugs. </li></ul>
  17. 17. Create A System For Prescribing <ul><li>It may be useful to review reference books or websites at this point to see if there are any contraindications or precautions to taking a particular drug with a coexisting medical condition or to taking the medication with a currently prescribed medication. </li></ul><ul><li>Some resources are very convenient such as Lexicomp’s electronic drug interaction software that allows you to enter the drug in question and cross check it for interactions. Importantly, pharmacists can also be consulted to clarify seemingly ambiguous information </li></ul>
  18. 18. Create A System For Prescribing <ul><li>In order to avoid drug toxicity the prescriber must be aware of how the drug will be eliminated when selecting a drug or determining dosages.   </li></ul><ul><li>This is especially important if the patient has known renal or hepatic disease, since these are the most common routes of elimination.   </li></ul><ul><li>If they are available, some laboratory values may serve as guidelines for prescribing drugs eliminated by the kidney or liver </li></ul>
  19. 19. Guidelines for compromised renal or hepatic function If greater than 4 times normal, do not use drugs that are toxic to or metabolized by the liver 30-40 u/l AST, ALT, liver transaminases Acetaminophen Codeine Diazepam Erythromycin Ibuprofen Ketoconazole Lidocaine Lorazepam Prednisone Hepatic  One dose q 24 hrs  One dose q 8-12 hours  One dose q 8 hours  <10 ml/min  10-50 ml/min  >50 ml/min GFR (Creatinine Clearance) Amoxicillin Cephalosporin Penicillin Tetracycline Renal  Margin of safety for dental prescribing Range Lab test Examples of dental drugs eliminated Potential impairment
  20. 20. Dealing with Patients of advanced age <ul><li>Patients of advanced age may be at increased risk of suffering the respiratory depressive effects of some medications such as benzodiazepines and opioids. </li></ul><ul><li>They may be less able to compensate quickly for medications that alter cardiovascular function, such as epinephrine </li></ul><ul><li>they may have an atypical adverse drug response such as altered mental status. </li></ul>
  21. 21. Dealing with Patients of advanced age <ul><li>It should be noted few adverse drug events have been clearly attributed to the changes that occur in the processes of absorption, distribution, and elimination as a result of normal aging. </li></ul><ul><li>Risks associated with altered drug metabolism and elimination are almost always due to the presence of a known systemic disease affecting cardiac, kidney, or liver function </li></ul>
  22. 22. Dealing with Patients of advanced age <ul><li>Some drugs present an increased risk of toxicity in older individuals, even without a drug interaction.  In addition to screening for potential adverse drug interactions knowledge of maximum doses of the drugs to be prescribed for a dental purpose is critical </li></ul>
  23. 23. Dealing with Patients of advanced age <ul><li>  A decrease in dosage for aged individuals may be recommended for some medications commonly used in dentistry  Due to normal physiologic changes in elimination associated with aging and altered distribution as a result of decreased body mass, dosage of these drugs should be reduced by 50% or to the lowest therapeutic dose for individuals under 100 pounds and patients over 85 years old </li></ul>
  24. 24. Dealing with Patients of advanced age Renal Elimination Fluconazole Antifungal Amoxicillin Cephalosporin Tetracycline Antibiotic Drug Drug class
  25. 25. Dealing with Patients of advanced age Hepatic Elimination  Diazepam Lorazepam Sedative/anxiolytic Lidocaine Local anesthetic Erythromycin Antibiotic Ibuprofen Pain reliever Drug Drug class
  26. 26. Dental Toxicology HEAVY METALS AND ANTIDOTES
  27. 27. HEAVY METALS AND ANTIDOTES
  28. 28. Lead <ul><li>Absorption </li></ul><ul><ul><li>Skin: alkyl lead compounds, because of lipid solubility (methyl and tetraethyl lead) </li></ul></ul><ul><ul><li>Inhalation: up to 90% depending upon particle size </li></ul></ul><ul><ul><li>GI: adults 5 to 10%, children 40% </li></ul></ul>
  29. 29. Lead <ul><li>Distribution </li></ul><ul><ul><li>Initially carried in red cells and distributed to soft tissues (kidney and liver); redistributed to bone, teeth and hair mostly as a phosphate salt. </li></ul></ul><ul><ul><li>Half life in blood 30-60 days, bone 20-30 years </li></ul></ul>
  30. 30. Lead <ul><li>Rates of absorption and distribution are greatly influenced by dietary intake and body stores of phosphate, calcium and iron relative to lead </li></ul><ul><ul><li>high PO4, Pb storage in bone </li></ul></ul><ul><ul><li>high Vitamin D, Pb storage in soft tissue </li></ul></ul><ul><ul><li>low PO4, Pb sequestered in soft tissue </li></ul></ul><ul><ul><li>high Ca++, Pb sequestered in soft tissue </li></ul></ul>
  31. 31. Lead <ul><li>Mechanisms of toxicity </li></ul><ul><ul><li>Inhibition of heme biosynthesis. Heme is the essential structural component of hemoglobin, myoglobin and cytochromes. </li></ul></ul><ul><ul><li>Binds to sulfhydryl groups (-SH groups) of proteins </li></ul></ul>
  32. 32. Lead Mechanisms of toxicity
  33. 33. Lead <ul><li>Diagnosis </li></ul><ul><ul><li>(1) History of exposure </li></ul></ul><ul><ul><li>(2) Whole blood lead level </li></ul></ul><ul><ul><ul><li>Children: >25μg/dl treatments </li></ul></ul></ul><ul><ul><ul><li>Adults: >50 μg/dl candidates for treatment; > 80 μg/dl & symptomatic, treatment initiated, >120 μg/dl encephalopathy </li></ul></ul></ul><ul><ul><li>(3) Protoporphyrin levels in erythrocytes are usually elevated with lead levels > 40 μg/dl </li></ul></ul><ul><ul><li>(4) Urinary lead excretion >80 μg/dl </li></ul></ul>
  34. 34. Lead <ul><li>Symptoms </li></ul><ul><ul><li>(1)Acute - nausea, vomiting, thirst, diarrhea/constipation,hemoglobinuria, hypovolemic shock </li></ul></ul><ul><ul><li>(2)Chronic - </li></ul></ul><ul><ul><ul><li>GI: lead colic (nausea, vomiting, abdominal pain) </li></ul></ul></ul><ul><ul><ul><li>CNS: lead encephalopathy (headache,irritation, insomnia, CNS edema) </li></ul></ul></ul>
  35. 35. Lead <ul><li>Treatment </li></ul><ul><ul><li>(1) Remove from exposure </li></ul></ul><ul><ul><li>(2) chelating agents </li></ul></ul><ul><ul><ul><li>CaNa2EDTA </li></ul></ul></ul><ul><ul><ul><li>2,3-dimercaptopropanol (Dimercaprol, BAL) </li></ul></ul></ul><ul><ul><ul><li>2,3-dimercaptosuccinic acid (Succimer) </li></ul></ul></ul><ul><ul><ul><li>D-penicillamine </li></ul></ul></ul>
  36. 36. Mercury (Hg) <ul><li>Absorption </li></ul><ul><li>GI: </li></ul><ul><ul><li>inorganic salts are variably absorbed (10%) but may be converted to organic mercury (methyl and ethyl in the gut by bacteria) </li></ul></ul><ul><ul><li>organic compounds are well absorbed >90% </li></ul></ul><ul><li>Inhalation: elemental Hg completely absorbed </li></ul>
  37. 37. Mercury (Hg) <ul><li>Distribution depends upon sources of exposure </li></ul><ul><ul><li>Elemental Hg (vapor) crosses membranes well and rapidly moves from the lung to the CNS. </li></ul></ul><ul><ul><li>Organic salts (lipid soluble) are evenly distributed, intestinal (intracellular)-fecal elimination. </li></ul></ul><ul><ul><li>Inorganic salts concentrate in blood, plasma and kidney (renal elimination). </li></ul></ul><ul><li>Half life is 60 to 70 days. </li></ul>
  38. 38. Mercury (Hg) <ul><li>Mechanisms of toxicity </li></ul><ul><ul><li>destruction of mucosal membranes </li></ul></ul><ul><ul><li>necrosis of proximal tubular epithelium </li></ul></ul><ul><ul><li>inhibition of sulfhydryl (-SH) group containing enzymes </li></ul></ul>
  39. 39. Mercury (Hg) <ul><li>Diagnosis </li></ul><ul><ul><li>History of exposure </li></ul></ul><ul><ul><li>Blood mercury </li></ul></ul>
  40. 40. Mercury (Hg) <ul><li>Symptoms </li></ul><ul><li>Acute </li></ul><ul><ul><li>(inorganic salts) degradation of mucosa-GI pain, vomiting, diuresis, anemia, hypovolemic shock, renal toxicity. </li></ul></ul><ul><ul><li>(organic) CNS involvement- vision, depression,, insomnia, fatigue, diuresis. </li></ul></ul><ul><li>Chronic: CNS symptoms similar to acute organic poisoning </li></ul>
  41. 41. Mercury (Hg) <ul><li>Treatment </li></ul><ul><ul><li>Remove from exposure </li></ul></ul><ul><ul><li>Hg and Hg salts > 4 μg/dl : 2,3-dimercaptopropanol (BAL),penicillamine, most effective is N-acetyl-penicillamine </li></ul></ul><ul><ul><li>(3) Methyl Hg- supportive treatment (nonabsorbable thiol resins can be given orally to reduce methyl Hg level in the gut). </li></ul></ul>

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