Antibiotics (Part 1) PDF

Antibiotics (Part 1) Dr. Dina Abdel Hamid Derbala Lecturer of Oral and Maxillofacial Surgery Oral Surgery Division - BMC - Jeddah Antimicrobial Agents Antimicrobial Agents A pharmaceutical antimicrobial medications that Antibiotics d...

Antibiotics (Part 1) Dr. Dina Abdel Hamid Derbala Lecturer of Oral and Maxillofacial Surgery Oral Surgery Division - BMC - Jeddah Antimicrobial Agents Antimicrobial Agents A pharmaceutical antimicrobial medications that Antibiotics destroy “kill” or slow down “inhibit” the growth of bacteria. Antimicrobial Antifungals A pharmaceutical fungicide or fungistatic are Agents used to treat and prevent fungal infections (mycosis) A pharmaceutical medications that help the Antivirals body to fight or to prevent viral infections. Antibiotics Learning outcomes: Describe the use of antimicrobials in dentistry including their indication, contraindication, adverse drug reaction and interaction.  Outline 1-Introduction 2-Classification of Antibiotics 3-Mechanism of Action of Different Antibiotics 4-Combination of Antibiotics 5-Dental Indications of Antibiotics 6-Adverse Effects of Antibiotics 7-The most commonly used Antibiotics in Dentistry The most commonly used antibiotics in Dentistry The most commonly used antibiotics in Dentistry Introduction Bacterial cell -Bacteria is a unicellular organisms. -It has a relatively simple cell structure compared to human cell. -It has a cell wall and cell membrane (phospholipid bilayer). -It does not have nucleus nor mitochondria. -It has a genetic material (DNA or RNA) in the intracellular space called the nucleoid. and flagella for movement Gram positive and Gram negative Bacteria: -Gram-positive and gram-negative refer to two broad categories of bacteria distinguished by their response to the Gram stain test. This test involves staining bacterial cells and is used to categorize bacteria based on their cell wall structure. -Gram-positive bacteria retain the violet stain, while gram-negative bacteria do not and are counterstained pink.  Gram positive and Gram negative Bacteria: This differentiation is important in determining appropriate antibiotic treatment, as different bacteria may respond differently to various antibiotics. Antibiotics They are medications used to prevent and treat bacterial infections by killing or inhibiting the growth of bacteria. Classification of Antibiotics (1) According to the Source Antibiotics Natural Synthetic Semisynthetic Penicillin Sulfonamides Ampicillin Erythromycin Quinolones Amoxicillin (2) According to Antimicrobial Spectrum (Range of Activity) Narrow-Spectrum Antibiotics Broad-Spectrum Antibiotics Antibiotics that are effective against only a Antibiotics that are effective against a single or a limited group of microorganisms. wide variety of microbial species. (kills just gram +ve or gram_ve bacteria). (either gram +ve or _ve bacteria) Useful in Treating Simple Useful in Treating Complex Odontogenic Infections Odontogenic Infections Extended-Spectrum Antibiotics Antibiotics with an extended range of activity that are effective against gram-positive organisms and some gram-negative bacteria Useful in treating infections caused by multi drug resistant bacteria. (3) According to Mode of Action on Microorganism ( Effect On Microorganisms) BACTERIOSTATIC ANTIBIOTICS BACTERICIDAL ANTIBIOTICS -Stop or slow the growth of bacterial cell : - Destroy (Kill) the bacterial cell : -They limit the spread of infection until the - They Kill bacteria, they are drugs of choice body’s immune system attacks and eliminates the pathogen. in seriously ill patients. Mechanism of Action of Different Antibiotics Mechanism of Action of Different Antibiotics Inhibition of Inhibition of cell wall synthesis bacterial metabolism Suppression of Inhibition of ribosomal deoxyribonucleic acid protein synthesis (DNA) synthesis Combination of Antibiotics Indications of Antibiotics Combination 1) To obtain broader spectrum for antibiotic effect (Augmentin: Amoxicillin & Clavulanic acid) 2) To manage mixed bacterial infection (Dental Infections such as periodontitis), Periodontitis is a gingival disease that damages soft tissue and destroys the bone that supports teeth. 3) To manage serious bacterial infection (Meningitis) 4) To overcome resistant bacterial strains (Tuberculosis (TB) and syphilis ($)) 5) To reduce the toxicity of one drug by using smaller doses of two drugs. Results of Antibiotics Combination Bactericidal (Penicillin) + Bactericidal (Aminoglycoside) = Synergism ▪ Synergistic effect occurs when the sum of the combined effect of the two drugs is greater than the sum of each individual action (1+1 = 3) Bacteriostatic (Tetracycline) + Bacteriostatic (Sulphonamide) = Addition ▪ Addition effect occurs when the combined effect of two or more chemicals is equal to the sum of the effect of each agents given alone (1+1=2). Bactericidal (Penicillin) + Bacteriostatic (Erythromycin) = Antagonistic (opposite of synergism) It occurs when the effect of the drug is reduced or inhibited by the presence of another drug. So, the combined effect is less than the sum of their individual effects. Bactericidal (Penicillin) + Bacteriostatic (Sulfadiazine) = Synergism Dental Indications of Antibiotics Dental Uses of Antibiotics Antibiotics Prophylactic Therapeutic Prophylactic Antibiotic Indications “Antibiotic Prophylaxis: The Antibiotic is given before invasive dental procedures to prevent bacterial infections in individuals who have certain risk factors for bacterial infections due to impaired host defenses. Dental Indications for Antibiotic Prophylaxis as: Antibiotics (A) Prophylaxis Against Infective Endocarditis: (B) End Stage Renal Diseases “ESRD” (C) Prophylaxis Against Prosthetic Joint Infection (D) Cancer, and some cardiac problems Invasive Dental Procedures Non-Invasive Dental Procedures Placement of matrix bands Injection of Local anesthesia Subgingival restorations Supragingival restoration Subgingival scaling Supragingival scaling Endodontic treatment before apical stop establishment Radiographs Incision and drainage of an abscess Screening Dental Extraction and Oral surgery Removal of sutures Dental implant Placement of orthodontic appliance  Terminology Infective Endocarditis: it is an infection of the inner lining of the heart, bacteria from mouth would enter into the blood stream during invasive dental procedure. Prosthetic Joint Infection:it occurs when bacteria infect the tissue surrounding a prosthetic joint (as hip or knee prosthetic joint) Matrix band:it is a thin flexible metal strip used to create a temporary wall around a tooth to assist in placing and shaping of dental restoration. Subgingival scaling: it involves removal of plaque and calculus from below the gingival line and pockets. Screening:a quick assessment of individual health status Orthodontic appliance: braces  Therapeutic Antibiotic Indications The antibiotic is given after a bacterial infection. Types EMPIRIC THERAPY DEFINITIVE THERAPY Antibiotic is directed against an anticipated (expected) Antibiotic is directed against an identified causative causative microorganisms. microorganism Based on clinical judgement and knowledge Specific bacterium causing the infection is identified The specific bacterium causing the infection is by culture and sensitivity test. unknown Therapeutic Antibiotic Indications  Terminology Lymphadenopathy: Enlargement of lymph nodes due to infection (it is a part of the immune system). Pericoronitis: it is an inflammation of soft tissue surrounding the crown of partially erupted tooth. Dry socket: is a painful complication after tooth extraction (no infection). Osteomyelitis: infection of bone. Cellulitis: it is a bacterial infection affects the deeper layer of the skin. Culture and Antibiotic Sensitivity Testing: - Culture and Antibiotic Sensitivity Testing : is a laboratory procedure used to identify the specific microorganism causing the infection to determine the most effective antibiotic to treat it. -A sample is collected from the infected site and cultured in a lab to grow the microorganism, then different antibiotic are tested against the cultured microorganism to see which one is most effective. Indications for Culture and Antibiotic Sensitivity Testing 1) Compromised host immunity [e.g., AIDS – Leukemia] 2) Rapidly progressive infection 3) Nonresponsive infection (after >48 h) 4) Recurrent infection 5) Infections treated by previous multiple antibiotic therapy FIVE RIGHTS FOR ANTIBIOTIC DRUG ADMINISTRATION ROUTE OF ADMINISTRATION Oral Route: ▪ For treatment of patients with mild to moderate infections that are managed on an outpatient basis. ▪ Drug form: syrup, suspension, tablets or capsules. Parenteral Administration (IV/IM): ▪ For treatment of patients with severe infections in order to maintain a high serum concentrations of antimicrobial agents. ▪ It is used for drugs that are poorly absorbed from the gastrointestinal tract ▪ Drug form: ampules or vials.  Antibiotic Resistance (AMR) Antimicrobial resistance occurs when microorganisms such as bacteria develop the ability to withstand the effects of antibiotic drugs. This makes the standard treatments ineffective and can lead to the persistence of infections, increased risk of spread, and higher mortality rates. The misuse and overuse of antimicrobial drugs in humans is significant contributors to the development of antimicrobial resistance. This global issue requires coordinated efforts across healthcare and public health to address and manage effectively. Adverse Effects of Antibiotics 1- Allergy 2- Gastrointestinal issues 2- Antibiotic Resistance 3-Oral Fungal Infection 5-Nephrotoxicity (toxic effects on the kidney) 6- Tooth Discoloration 7- Vitamin B Deficiency 8- Ototoxicity (toxic effect on the ear- hearing loss) Terminology: Pharmacokinetics: It is the branch of Pharmacology concerned with the movement of the drug within the body (Absorption, distribution, metabolism, excretion). Pharmacodynamics: It is a field of Medicine that deals with the use of drugs and clinical application (dosing, drug interaction, ……). Cap: stands for capsules Tab: stands for tablets PO: It means that the medication should be taken orally(by mouth). I.V: Intravenous IM: Intra muscular Rx: Prescription OD: Once daily BID: 2 times/ day TID: 3 times/ day QID: 4 times/day gm: stands for gram mg: stands for milligram The most commonly used antibiotics in Dentistry The most commonly used antibiotics in Dentistry Inhibition of cell wall Inhibition of (DNA) Inhibition of ribosomal synthesis protein synthesis synthesis Macrolides BETA-LACTAM ANTIBIOTICS : (Azithromycin, Erythromycin, METRONIDAZOLE Clarithromycin) (Flagyl) PENICILLIN LINCOSAMIDES (Amoxicillin) (Clindamycin) CEPHALOSPORINS (Cephalexin) TETRACYCLINES AMINOGLYCOSIDES (Gentamycin) Beta-lactam antibiotics Beta-lactam Antibiotic -Beta lactam antibiotics are a class of antibiotics that are widely used in the treatment of bacterial infections. -They drive their name from the beta lactam ring structure that is a key component of their molecular structure. The beta lactam ring works by inhibiting bacterial cell wall synthesis leading to bacterial cell death. -Beta lactam antibiotics include Penicillin, Cephalosporins, and monobactam. The basic structure of beta lactam antibiotics is the B- Lactam ring (red) Penicillin Penicillin ▪ Penicillin is the first used antibiotic in Medicine.. ▪ It is a natural penicillin. (derived from fungus penicillium). ▪ Penicillin is a generic term for a group of antibiotics that have a similar mechanism of action and adverse drug reactions as they share the same basic structure. ▪ Penicillin works by Inhibition of bacterial cell wall synthesis. ▪ It is a Bactericidal. ▪ Penicillin antibiotics have a broad spectrum of antimicrobial activity that is not shown by any other antibacterial class.. ▪ Penicillin cover gram-positive, gram-negative, aerobic and some anaerobic organisms. Types of Penicillin Ampicillin: - It is a semisynthetic Penicillin. - Less commonly used in dentistry due to its administration route and gastrointestinal side effects. Penicillin G: - It is a natural penicillin. - Long-acting penicillin used for prophylaxis against specific infections, not commonly used in routine dental practice. -More common in treatment of syphilis and other non-oral infections. Syphilis: It is a sexually transmitted disease. Penicillin V: -It is a natural penicillin. - Typically used for oral infections due to its effectiveness against oral streptococci. - Used for mild to moderate oral infections and as prophylaxis for dental procedures in patients at risk of infective endocarditis. Amoxicillin : The most commonly used type in dental Practice.(semisynthetic) Pharmacokinetics of Penicillin Absorption: ▪ Oral penicillins are absorbed mainly in the duodenum and the small intestine. Distribution ▪ Penicillins are distributed widely to most areas of the body (lungs, liver, kidneys, muscles & bone). ▪ Penicillin can penetrate CSF (cerebrospinal fluid) only during meningitis. ▪ They cross placental barrier but they are not teratogenic. Teratogenic refers to an abnormal fetal or birth defects caused by a drug or chemical, when exposed to them during pregnancy. Excretion ▪ Penicillin are excreted unchanged by the kidneys and appear in urine. (Penicillin dosage should be adjusted in renal impairment patients). Pharmacotherapeutics for Routine Management Of Odontogenic Infections Penicillin: − It was the recommended first choice antibiotic in the past. Amoxicillin: − It is the most widely prescribed drug for management of acute dentofacial infection in current practice. − It is a broad spectrum antibiotic that covers a wide range of oral pathogens. − It is a semisynthetic antibiotic. − It has a longer serum half-life than penicillin and ampicillin.(means how quickly the drug is eliminated from the body) − Its long serum half-life results in effective duration of action and longer dosage interval with improved patient compliance. Pharmacotherapeutics Adult Therapeutic Dosages: Amoxicillin 500 mg Cap PO TID / 5 days. Amoxicillin with Clavulanic acid (Augmentin): – Mild to moderate infection: Rx: Augmentin 625 mg tab PO BID / 5 days – Severe infection: Rx: Augmentin 1 gm tab PO BID / 5 days -Clavulanic acid extends the antibiotic spectrum of activity to include bacteria that produce beta-lactamases (resistant bacteria). -B lactamase: is an enzyme produced by certain bacteria that is resistant to B lactam antibiotics as Amoxicillin. Ampicillin 500 mg vial I.V. QID / 5 days Pharmacotherapeutics of Amoxicillin Adult Prophylactic Dosages: Amoxicillin 2 gm cap PO 30–60 Minutes before procedure.(4 tablets as every one is 500 mg) Ampicillin 2 gm vial I.V. / I.M. 30–60 Minutes before procedure. Pharmacotherapeutics Safety in Pregnancy : ▪ Penicillin (including Amoxicillin and Ampicillin ) are considered safe during pregnancy. Safety in Lactation: ▪ Penicillins are excreted in breast milk. ▪ Penicillins are considered to be compatible with breastfeeding. Allergy: ▪ Penicillins carry a relatively higher risk of allergy than other dental antibiotics. ▪ Penicillins allergy occur in about 5% of the population. Adverse Reactions 1) Hypersensitivity: (Allergy): ▪ It affects approximately 5% percent of the population and it may be presented clinically as: − Mild local skin rashes or angioedema (marked swelling of the lips, tongue, and periorbital area) − Generalized Anaphylaxis (severe life threatening allergic reaction) symptoms can include : difficulty in breathing, swelling, hives, drop in blood pressure). 2) Diarrhea (Pseudomembranous Colitis (PMC): ▪ It is common with antibiotics that are incompletely absorbed and have an extended antibacterial spectrum. 3) Neurotoxicity: as a side effect of amoxicillin is rare ( confusion, seizures) N.B: Penicillin & Aminoglycosides (Gentamycin): ▪ The antibacterial effects of all B-Lactam antibiotics are synergistic with the aminoglycosides (Gentamycin). ▪ Penicillin inhibits cell wall synthesis and facilitate the entry of aminoglycosides to inside the bacterial cell. Drug Interactions Some drugs can interact with Penicillin antibiotics, affecting their effectiveness. Drugs Affecting The Penicillin Tetracyclines antibiotics They reduce the bactericidal action of Penicillin. Probenecid Increase the level of Penicillin in the blood by reducing (Medication used to treat its excretion, so enhancing the effectiveness. gout and kidney stones) Neomycin It decreases the absorption of penicillin V (Aminoglycoside Antibiotic) Drug Interactions Drugs Affected by the Penicillin Oral Contraceptives can reduce the effectiveness of birth control pills, leading to unintended pregnancy. Methotrexate Increases the risk of methotrexate toxicity. (Medication used to treat cancer and some autoimmune disease) Anticoagulant Increases the effect of anticoagulant (warfarin) (blood thinner) leading to increased risk of bleeding. Reference Reference: Chapter 33: Pharmacology of Specific Drug Groups: Antibiotic Therapy Thank You