Drugs Commonly Used in Dentistry: Lecture 4 PDF

Drugs Commonly Used in Dentistry: I Prof Najla Dar-Odeh Modified by: Dana Nabeel Corrected by: Marah Islim Objectives ▪ This is the first of two lectures on drugs commonly used in dentistry ▪ By the end of this lecture you should be able to recognize th...

Drugs Commonly Used in Dentistry: I Prof Najla Dar-Odeh Modified by: Dana Nabeel Corrected by: Marah Islim Objectives ▪ This is the first of two lectures on drugs commonly used in dentistry ▪ By the end of this lecture you should be able to recognize the following: ▪ 1. routes of drug administration and drug elimination ▪ 2. Antimicrobials including antibiotics and antifungals Introduction ▪Dentists are legally entitled to prescribe medications, however dental prescribing is restricted to those drugs contained within the list of dental preparations allowed by the law. Dentists have duty to prescribe only within their competence and adhere to guidance from their local formulary authority. Dentists legally have duty to prescribe medications that are only related to conditions of the oral cavity. Common Terms ▪Drug: any substance which changes a physiological function or modifies a disease process ▪Dose : the amount of drug taken at any one time ▪Form of a drug : is the drug formulation such as tablet, capsule, liquid suspension/solution, ointment/cream  Route of Drug Administration ▪ Most drugs prescribed by dentist are taken orally (by mouth) and are subsequently absorbed from the gastro intestinal tract In the form of a suspension, tablet, or capsule, or topical like gels or ointments ▪ Some drugs should be taken on an empty stomach(1 hour before eating or 2 hours after eating) as food could delay absorption. Others cause gastrointestinal irritation and so should be taken after meals to reduce such irritation  Route of Drug Administration ▪Parenteral drug administration (intra-venous, intramuscular, or subcutaneous) is indicated when: 1.Patient is unable to take drugs orally (patients who are nauseous or are vomiting) 2.Drug is liable to destruction by stomach acidity (Penicillin G) 3.Absorption disorders (Malabsorption) 4.A quick serum concentration needs to be achieved ( e.g. serious life-threatening infections)  Drug Elimination ▪ Once the drug has exerted its actions it must be eliminated from the body. In General, drugs are metabolized (detoxified) in the liver and excreted via the kidneys Drugs Commonly Used in Dentistry ▪ 1.Antibiotics ▪ 2. Antifungal drugs Antimicrobials ▪ 3. Antiviral drugs ▪ 4. Analgesics/anti-inflammatory drugs ▪ 5. Anti-anxiety drugs ▪ 6.Corticosteroids ▪ 7. Topical and local anesthetics  Antibiotics Some dentists are not sure whether the surgical technique they used was aseptic enough or not, so to cover this malpractice they prescribe antibiotics, which is inappropriate. Antibiotics are the most widely abused drugs on the basis of inappropriate (indications, dosage, and duration) of use. Dentists prescribe about 7%-11% of all common antibiotics. Inappropriate use in Dentistry include: 1. Antibiotics therapy initiated after surgery to prevent an infection 2. Failure to use prophylactic antibiotics according to the principles established for such use. the treatment by do a 3. Use of antibiotics as analgesics in Endodontics. good RCT or extraction not by giving antibiotic 4. Over use in situations patients are not at risk. Regarding point 2: For example: certain patients are at risk of developing infective endocarditis, these patients are identified according to certain guidelines and are given antibiotics accordingly, but some dentists prescribe antibiotics for any patient with any kind of heart condition because they fear the risk of infective endocarditis, which is inappropriate. Antimicrobials affect the viability of micro-organism by: 1. Inhibition of cell wall synthesis 2. Alteration of cell membrane integrity 3. Inhibition of ribosomal protein synthesis 4. Suppression of DNA 5. Inhibition of Folic Acid Synthesis  Antibiotics Classification ▪ Antibiotics are classified according to their activity spectrum into: 1. Narrow-spectrum antibiotics: affect only a limited range of organisms, such as Gram-ve or Gram +ve bacteria (PenicillinV, PenicillinG)Also called: Benzylpenicillin Also called: Phenoxymethylpenicillin 2. Broad-spectrum antibiotics: affect a wide rrange of Gram-ve and Gram+ve bacteria (Tetracyclines) 3. Extended-spectrum antibiotics: have bacterial activity in-between narrow and a broad-spectrum agent (Amoxicillin)  Microbiology of Oral Infections These bacteria are also the most common oral bacterial strains which cause infective endocarditis * Most oral infections are caused by a mixture of micro-organisms. Streptococci are the most frequently involved and streptococcus viridans is the most common (all susceptible to Penicillin) It is considered a skin type of bacteria but still could be found in the oral infections * Staphylococcus aureus is sometimes found in oral infections, 10- 20% appear to be resistant to Penicillin (as they produce penicillinase enzyme) * Gram negative anaerobes may contribute to infections of periodontal origin (Periodontitis, pericoronitis) acute necrotizing gingivitis/periodontitis,  Penicillin ▪Penicillin is the antibiotic most commonly used to treat oral bacterial infections, essentially because pathogens of the oral flora are highly susceptible to penicillin ▪Types of penicillin: ▪1. Narrow spectrum penicillins: Penicillin V and Penicillin G ▪2. Penicillinase-resistant Penicillins :(Dicloxacillin) ▪3. Extended spectrum Penicillins: Amoxicillin and combination of Amoxicillin and clavulanate  Penicillin V and Penicillin G Penicillin V: Effective against both Gram+ve and Gram-ve organisms of the oral flora. Not effective, however, against penicilinase- producing staph aureus Typically used in Europe. Because they are narrow-spectrum, they do not contribute to the development of anti microbial resistance. Penicillin G: is not commonly prescribed in dentistry as it is completely destroyed by acid in the stomach and it is only available for parenteral administration  More commonly used in our region Not commonly used Amoxicillin, Augmentin, and Dicloxacillin 1. Amoxicillin has a broader spectrum of bacterial activity than Penicillin V and it is not affected by food content of the stomach. 2. Amoxicillin + Clavulanate Clavulanate blocks the actions of penicillinase and so extends the spectrum of Amoxicillin to cover penicillinase producing staph aureus. 3. Dicloxacillin: Effective against penicillinase-producing staphylococci. Usually prescribed only if suggested by a culture and sensitivity test Macrolides Usually prescribed to patients allergic to Penicillin 1. Erythromycin: Poorly absorbed and gastrointestinal distress is very common Was used heavily in the past. Bacteria rapidly develops anti microbial resistance to it. 2. Azithromycin : More completely absorbed, with less gastrointestinal distress. Dose: 500 mg on day 1, then 250 mg once/day for 4 days Short course of treatment, associated with better patient’s compliance 3. Tetracycllines: Poorly absorbed as it is much affected by food content specially antacids, dairy products, iron and magnesium 4. Doxycycline: 200 mg initial dose followed by 100 mg daily An “excellent” antibiotic usually used for periodontal disease  Tetracyclines: Side Effects and Contra-Indications Contraindicated for pregnant patients and children less than 8 years of age. readily deposited into teeth during calcification which can cause a yellow-gray-brown discoloration (Permanent discoloration) Photosensitivity reaction (Specially with Doxycycline) Could cause some burns Tetracyclines are readily degradable by a large number of anti- epileptic drugs, and are so not indicated for epileptic patients Cephalosporins ▪ Cephalosporins have a spectrum similar to that of Augmentin (Amoxicillin + clavulanate = Augmentin) ▪ Most Cephalosporins are poorly absorbed. ▪ Cephalosporins should not be prescribed to patients allergic to Penicillin since there is a 10% cross-reactivity with the Cephalosporins ▪ Cephalosporines are usually prescribed when suggested by a culture and sensitivity test Not the first choice of antibiotic for orofacial or dental infections Metronidazole An “excellent” antibiotic for anaerobic infections, used in treating periodontitis, necrotizing ulcerative gingivitis/periodontitis and pericoronitis ▪Concentrates highly in the crevicular fluid and gingival tissue. ▪used in the treatment of refractory periodontitis ▪Metronidazole is not recommended for the treatment of odontogenic infections as it is not effective against Streptococcus viridans it's not recommended in case of cellulitis  Clindamycin ◉ Clindamycin is superior to other antibiotics against anaerobes (chronic infections) ◉ Its use is usually limited to cases refractory to other antibiotics, or if suggested by culture and sensitivity Dose : 150–450 mg orally tid-qid (3-4 times a day, according to the severity of the infection) Serious side effect: life-threatening colitis - Clindamycin causes diarrhea and pseudomembranous colitis - Was recently excluded from the antibiotic prophylactic regimen of infective endocarditis because of its side effects. Bacterial Infections ▪Prolonged courses of antibiotic treatment can encourage the development of drug resistance and therefore the prescribing of antibiotics must be kept to a minimum and used only when there is a clear need. Antibiotics are contraindicated for the following oral conditions Most orofacial infections are NOT treated by antibiotics Reversible pulpitis Irreversible pulpitis Periapical periodontitis Localized dentoalveolar abscess Dry socket Plaque-induced gingivitis Chronic periodontitis Most of these conditions can be treated by operative treatment: caries removal,endodontic treatment, extraction  Empirical means prescribing the antibiotic before culture and sensitivity testing Empirical antibiotic prescribing is indicated for the following oral infections 1. Facial cellulitis 2. Lateral periodontal abscess 3. Pericoronitis 4. Bacterial sialadenitis Bacterial Infections In patients who are allergic to penicillin, an appropriate 5- day regimen is: 1. Metronidazole Tablets, 200 mg TID 2. Erythromycin Tablets, 250 mg QID + Azithromycin or Clindamycin as well Bacterial Infections 2. Acute Necrotising Ulcerative Gingivitis and Pericoronitis: + other anaerobic infections *Metronidazole Tablets, 200 mg TID (3 days), or *Amoxicillin Capsules, 250 mg TID  Antibiotics Use in the Management of Life-threatening infection: For example: facial cellulitis which spreads to the eye, ludwig’s angina which jeopardizes the airways Infections might spread through tissue planes, lymphatic vessels or facial veins and could result in compromise of functions and neurological manifestations Signs and symptoms of life-threatening spreading infections: Airway obstruction Difficulty in swallowing Peri-orbital edema Obliteration of the nasolabial fold Confusion, delirium or stupor Management: ▪ 1. Hospitalization & communication with a physician ▪2. Culture & sensitivity with initiation of high dose intravenous antibiotics ▪3. When the patient is stabilized, removal of the source of infection is carried out For example: Drainage of the area, extraction of the offending tooth, endodontic treatment Identifying Causative Microorganisms as Part of the Management of Dental Infections ▪Culture and sensitivity test are indicated in the following conditions: ▪Failure of the patient to respond to the initial antibiotic therapy Immunocompromised patients susceptible to recurrent infections (example: COPD disease patients) ▪Patients with atypical oral flora (long term antibiotic use, uncontrolled diabetes) ▪Life-threatening spreading infections ▪Immunocompromised patients or those on immunosuppressive drugs (HIV patients)  If you prescribe an antibiotic for a patient, you have to follow up with them to monitor the development of any adverse effects Adverse Effects of Antibiotics ▪Superinfections (often fungal infections): For example: more common with broad-spectrum antibiotics amoxicillin for a long period of time ▪Gastrointestinal problems (nausea, vomiting, and diarrhea) Any type of antibiotic can cause GI symptoms, so they are not limited to Clindamycin ▪Antibiotic resistance You must know if the patient has taken any antibiotic course in the last month, because then you may have to change the type of antibiotic you are prescribing. ▪Allergic reactions : ranging from a mild rash to wheezing and anaphylaxis (Most severe and could be fatal) ▪Photosensitivity : exaggerated sunburn (Azithromycin mainly) ▪ More serious effects: hepatic and renal toxicity, life-threatening colitis (Clindamycin) Antifungal therapy Oral Candidasis, types 1. Primary infections restricted to the oral & perioral sites. 2. Secondary infections accompanied by systemic mucocutaneous manifestations. Clinical Presentation of Oral Candidiosis ▪ 1. Pseudomembraneous ▪ 3. Chronic hyperplastic ▪ 5. Angular cheilitis ▪ 2. Erythematous ▪ 4. Denture stomatitis ▪ 6. Median rhomboid glossitis  There are also oral and systemic antifungal treatments Topical antifungal treatment ►The topical antifungal agents commonly used are: ►polyenes (nystatin and amphotericin B), (First line antifungals) ►azoles (myconazole, ketoconazole, clotrimazole) ►triazoles (fluconazole and itraconazole).  The first and most important step in treatment process Management of Oral Candidiasis ▪ Identify and eradicate (reduce) any predisposing factors Iffactors, the patient has malnutrition, uncontrolled diabetes, poor denture, dry mouth or other predisposing they have to be addressed before prescribing the antifungal, otherwise it will not be effective. ▪ Poylenes (Nystatin suspension 5 ml of 100,000 units/ml, qid for 2 weeks or Amphotericin B lozenges 10 mg, dissolved in mouth qid for 2 weeks) are the It is used for a longer duration, unlike antibiotics which are used for a shorter period of time first choice in treating primary oral candidiasis. ▪They are well tolerated, not absorbed from the GI tract & are not associated with development of resistance Patients who have oral candidiasis may also have intestinal candidiasis, so by swallowing the antifungal, the effect will benefit the oral cavity and the intestines. Management of Oral Candidiasis ▪ 3. denture stomatitis: Clotrimazole cream (1%) applied to the tissue contact area of the denture (qid for 3 weeks) ▪ 4. angular cheilitis: Topical Miconazole (20 mg/g) is used as it affects both candida & staph aureus (qid for 2-3 weeks)  Management of Oral Candidiasis 5. Systemic azoles (Fluconazole, Ketoconazole) are used for: a. Therapy-resistant primary oral candidiasis In immunocompromised patients b. Deeply seated primary infections (chronic hyperplastic candidiasis) Inandthisneeds condition, candida is deeply seated in all layers of the epithelium oral or systemic therapy c. Secondary oral candidiasis Associated with systemic involvement Disadvantages of azoles: a. Development of resistance & cross resistance They become ineffective b. Toxicity and organ damage Watch out for hepatic failure, you have to monitor liver function enzymes regularly  Systemic Antifungal Drugs ▪Systemic antifungal drugs are also used to treat: ▪ deep fungal infections (histoplasmosis, blastomycosis and mucormycosis) Candida infections are usually superficial ▪ fungal infections in immunocompromised patients. Whether they are deep or superficial Treatment takes several months, or even a year or more ▪Commonly used drugs include: Fluconazole Ketoconazole Intravenous Amphotericin B (for up to 10 weeks) Systemic antifungal agents Ketoconazole Tablets 200 mg tabs taken once or twice a day with food for 2 weeks Fluconazole Capsules 100 mg caps once a day for 1-2 weeks Itraconazole Capsules 100 mg caps once daily taken immediately after food for 2 weeks  Difficulties in the treatment of oral candidosis are due to: a) poor patient compliance especially in topical administration Patient has to apply the antifungal gel 4-5 a day for a long period of time b) side effects caused by long treatment with systemic drugs, such as nausea, skin rash, abnormal results of liver function tests and hepatitis c) resistance to antifungal drugs particularly of the newer oral agents most notably fluconazole in patients with advanced HIV infection d) The multifactorial predisposing factors Which you have to identify before prescribing the antifungal  Further reading ▪ 1. Dar-Odeh NS, Abu-Hammad OA, Al-Omiri MK, Khraisat AS, Shehabi AA. Antibiotic prescribing practices by dentists: a review. Ther Clin Risk Manag. 2010 Jul 21;6:301-6. downloadable at: https://www.dovepress.com/articles.php?article_id=4639 2. Drug prescribing for dentistry Downloadable at: http://www.sdcep.org.uk/wp- content/uploads/2013/03/Drug_Prescribing_for_Dentistry_2_Web.pdf