Chapter 38 & 39 Antibiotics PDF

Year 2 Chapter 38 Principles of Antibiotic Therapy Chapter 39 Antibiotics Affecting the Bacterial Cell Wall Wilbert F. Cansino RN, MAN  ANTIBIOTICS Drugs used to manage infections are called antimicrobials, anti-infe...

Year 2 Chapter 38 Principles of Antibiotic Therapy Chapter 39 Antibiotics Affecting the Bacterial Cell Wall Wilbert F. Cansino RN, MAN  ANTIBIOTICS Drugs used to manage infections are called antimicrobials, anti-infectives, or antibiotics. Classification by Susceptible Organism Antibacterial drugs Antiviral drugs Antiretroviral drugs Antifungal drugs Antiparasitic drugs Antiprotozoal drugs Anthelminthic drugs.  ANTIBIOTICS Classification by Mechanism of Action Antimicrobial drugs work in a variety of ways: Inhibition of bacterial cell wall synthesis Inhibition of protein synthesis Inhibition of nucleic acid synthesis Inhibition of metabolic pathways (antimetabolites) Disruption of cell wall permeability Inhibition of viral enzymes  ANTIBIOTICS Either bacteriostatic or bacteriocidal. Bacteriostatic - drugs inhibit bacteria, but their effect is reversible if the drug is removed, unless the host defense mechanisms have eradicated the organism. Sulfonamides, erythromycin, and tetracyclines are examples of bacteriostatic drugs. Bacteriocidal - Antibiotics that actually kill bacteria. They depend less on the body’s defense mechanisms than bacteriostatic drugs do. Examples include beta-lactam antibiotics such as the penicillin and cephalosporins or aminoglycosides.  Antibiotic Affecting the bacterial cell wall 01 Penicillins Penicillinase-resistant Narrow-spectrum penicillins penicillins Penicillin (antistaphylococcal penicillins)(NA Broad-spectrum penicillins in OMAN) (aminopenicillins) Ampicillin Beta-lactamase inhibitors Amoxicillin Extended-spectrum penicillins Clavulanic acid (antipseudomonal penicillins) Piperacillin Antibiotic Affecting the bacterial cell wall Monobactum 05 Cephalosporins 02 Antibiotics( NA in First generation OMAN) 1. Cefazolin 03 Carbapenems 2. Cephalexin cilastatin-imipenem Second generation Meropenem 1. cefuroxime, Third generation 04 vancomycin 1. cefixime, 2. cefotaxime, Vancomycin 3. ceftriaxone, 4. ceftazidime Fourth generation 1. (cefepime)  Antibiotic Affecting the bacterial cell wall 01 Penicillins 04 Narrow-spectrum penicillins Penicillin Penicillinase-resistant Broad-spectrum penicillins penicillins (aminopenicillins) (antistaphylococcal Ampicillin penicillins)(NA in OMAN) Amoxicillin Extended-spectrum penicillins 05 (antipseudomonal penicillins) Beta-lactamase inhibitors Piperacillin Clavulanic acid  Beta lactam antibiotics Drugs with a chemical structure containing a beta-lactam ring that is essential for antibacterial activity. Resistance to beta-lactams, such as penicillin, may occur because of the bacteria’s ability to produce beta-lactamase.  01 Penicillins Antibiotic Affecting the bacterial cell wall  Narrow spectrum penicillins- Penicillin G Pharmaco-therapeutic Pharmaco-kinetics Pharmaco-dynamic Adverse Effect. gram-positive bacteria, It is absorbed from the (GI) inhibits the third and final The most serious adverse effect anaerobes, tract stage of bacterial cell wall allergic reaction: rash, fever, and and spirochetes, including  The average peak drug effect synthesis by binding to wheezing, and possibly anaphylaxis streptococci & staphylococci, is 4 hours specific penicillin- & death. and Treponema pallidum. it crosses the placenta and is binding proteins (PBPs) More common adverse effects this cause infections such as secreted in breast milk. located inside the GI tract: nausea, vomiting, diarrhea, pneumonia,  It does not penetrate the bacterial cell wall. Cell abdominal pain, glossitis, stomatitis, pharyngitis,tonsillitis, blood–brain barrier very well wall weakens. gastritis, sore mouth, and furry endocarditis, except in the presence of tongue. tetanus, anthrax, meningitis, meningeal inflammation, Other adverse effects include super syphilis, diphtheria, rat-bite thereby, it is useful in treating infections (e.g., yeast infections) and used as prophylaxis to prevent meningitis. local pain or inflammation at the bacterial endocarditis prior to It is rapidly cleared injection site. procedures(prosthetic heart unchanged from the plasma by less common effects include valves, mitral valveprolapse) & the kidneys lethargy, hallucinations, rheumatic fever anemia, thrombocytopenia, nephritis, and sodium overload Penicillins Assessment of relevant core patient variables: Assess for reaction to antibiotics. Perform a skin test to determine current allergic status. For elderly patients or patients with kidney disease, evaluate RFT and for long term therapy evaluate LFT Penicillins Assessment of relevant core patient variables: Assess if the women is taking contraceptive because it counteract the effects with this drug Give pregnant and lactating women penicillin G with caution because super infections may occur in the fetus or infant, or the infant may develop diarrhea.  Penicillins Assessment of relevant core patient variables: 2° and 8°C for up to 7 days Check IV site for signs Prepared solutions = room of phlebitis temperature for 24 hours 7 to 10 days, may continue for 2 weeks. Adequate fluid intake. Penicillins Patient And Family Education Patients who have allergic reaction to penicillin should never take any drug with a name that ends with “cillin.” Ø Completing the full course of Antibiotics. Ø Signs and symptoms of allergic reaction: Ø Rash Ø Welts Ø Itching Ø shortness of breath Ø To relieve a sore mouth or throat, sucking on ice chips may help. If diarrhea occurs, teach patients to increase fluid intake  IV antibiotic similar to cilastatin-imipenem. Used to manage abdominal infections 03 Carbapenems Appendicitis Peritonitis bacterial meningitis Nosocomial infections resistant to other antibiotics. Meropenem Hypersensitivity is the only contraindication.  Is a complex and unusual tricyclic glycopeptide antibiotic. It is the only drug in its class. 04 The use of vancomycin is limited by its ability to produce toxic effects. Because of its toxicity, vancomycin is used only when other vancomycin antibiotics fail to resolve an infection. Vancomycin It has been touted as able to eradicate most gram-positive pathogens  Vancomycin Pharmaco- Pharmaco- Pharmaco Adverse Effect therapeutic kinetics dynamic endocarditis,bone and joint Given IV , it is bactericidal Ototoxicity cochlear toxicity infections Peak level 1 hour after because it inhibits cell (tinnitus, hearing loss) or vestibular pseudomembranous colitis infusion. wall synthesis by toxicity (ataxia, vertigo, nausea caused by C. difficile.used In patients with normal renal altering the cell’s and vomiting, nystagmus). for gram-positive infections function, vancomycin has a permeability. it also Nephrotoxicity occur in patients in penicillin allergic serum half-life inhibits the synthesis of receiving other nephrotoxic drugs, patients. of 4 to 6 hours, but in elderly ribonucleic acid (RNA). such as aminoglycosides. used for penicillin- and patients or those with renal anaphylactoid reactions,fever, methicillin-resistant impairment, half-life can be as Because of this dual chills, tachycardia, pruritus. staphylococcal MRSA long as 146 hours. mechanism of action, Paresthesias, flushing, rash, or used with aminoglycosides Excret in urine &feces. resistance to redness in the face, neck, upper to combat Streptococcus vancomycin has been body, arms, or back called the “red faecalis and methicillin- limited to strains of man” or “red neck”syndrome. resistant organisms. group D streptococci. It is not used in treating The body is not directly meningitis because of affected. poor penetration into CSF.  Vancomycin Contraindications and Precautions Vancomycin is contraindicated for patients with hypersensitivity to it and for pregnant patients. Use it with caution in patients with renal disease, such as renal failure or renal impairment, and in patients receiving other drugs with the potential for nephrotoxicity, such as aminoglycosides. Drug Interactions Orally administered vancomycin should be avoided in patients receiving antihyperlipidemic drugs Vancomycin Assessment of relevant core patient variables: Assess the patient for nephrotoxicity and ototoxicity. Lower doses of vancomycin are recommended for patients with renal dysfunction or for patients receiving other ototoxic or nephrotoxic drugs. Assess gross hearing in patients with pre- existing hearing impairment. Vancomycin Assessment of relevant core patient variables: For patients with expected long-term therapy, perform a baseline CBC and hepatic and renal function tests  Vancomycin Assessment of relevant core patient variables: Note whether patients are elderly, because such patients are at higher risk for toxicity and drug accumulation because of their age-related decreases in renal function. It should not be given to pregnant women and should be given cautiously to breast-feeding women. Vancomycin Maximizing Therapeutic Effects Ensure that the patient receives the full course of vancomycin as prescribed, divided around the clock to increase effectiveness.  Vancomycin Minimizing Adverse Effects Ø Administer vancomycin over at least 60 minutes. Ø Ototoxicity after IV administration is believed to be associated with serum concentration ranges above 60 to 80 mcg/mL, which may occur when doses are too large or infused too rapidly. Ø Administering IV vancomycin too rapidly may also lead to red man syndrome. Ø Assess serum levels of drug.  Vancomycin Patient And Family Education Advise the patient of the importance of completing therapy. Explain the potential adverse effects and need for periodic blood monitoring. Advise the patient to report symptoms such as tinnitus,hearing loss, vertigo, or nausea and vomiting. Teach the patient the importance of accurate fluid intake and output measurements. Elderly patients may need vancomycin concentration monitoring 05 Cephalosporin Four generations of cephalosporins have been introduced 1st, 2nd, 3rd and 4th generation cephalosporins. considered beta-lactam antibiotics The major differences between the generations include their activity against They are similar to the gram-negative bacteria, their penicillins in structure and resistance to beta-lactamases, and their in activity. ability to distribute into cerebrospinal fluid.  Cephalosporin The first-generation cephalosporins have the least activity against gram- negative bacteria, and the fourth-generation cephalosporins have the most. The first-generation cephalosporins have little resistance to beta-lactamases; resistance increases in second and third generations, with the fourth generation having the most resistance. First - and second-generation cephalosporins have poor distribution into cerebrospinal fluid, and third- and fourth generation cephalosporins have good distribution.  First generation cefazolin Pharmaco- Pharmaco- Pharmaco- Adverse Effects therapeutic kinetics dynamics Used to treat many It is rapidly it produces its Hypersensitivityreactions kinds of infections skin, absorbed after IM bactericidal GI tract. Nausea, vomiting, bone, heart, blood, injection. effects by binding diarrhea, anorexia, respiratory tract, GI tract, Peak effect occurs with PBPs, which abdominal sinus, ear, and urinary within 1.5 to 2 hours. disrupts bacterial pain, and flatulence tract. It is administered by cell wall CNS symptoms headache, the IV route, with synthesis. dizziness, lethargy Used for perioperative immediate onset and It activates Others prophylaxis in surgeries peak effect in 5mnt autolysins, which Nephrotoxicity involving the GI or It is excreted results in additional Superinfections related to genitourinary tracts, unchanged in urine. damage to the cell the normal flora having been bone, and skin. wall, allowing the destroyed. cell to swell and Thrombophlebitis and then burst from the abscess at the injection osmotic pressure site within the cell.  Cephalosporin  Cefazolin is contraindicated in anyone with a known allergy to cephalosporins.  Caution must be used in patients with renal failure and in pregnant or lactating patients.  Cephalosporin Drug Interactions Risk for nephrotoxicity when cefazolin is given concurrently with aminoglycoside antibiotics. Patients receiving oral anticoagulants may experience increased bleeding when also given cefazolin. Reaction includes flushing, shortness of breath, nausea and vomiting, chest pains, palpitations, dizziness and faintness, confusion, sweating, blurred vision, and possibly respiratory depression, seizures, and unconsciousness. Cephalosporin Assessment of relevant core patient variables: Assess for pregnancy and lactation. Cefazolin is not recommended for infants younger than 1 month because of their immature renal and hepatic functioning. Assess for the patient’s use of alcoholic beverages.  Cephalosporin Minimizing Adverse effects:  Cefazolin may be taken with food or fluids to decrease GI distress.  Administer IM cefazolin deep into a large muscle.  Monitor the patient’s hydration status and ensure that adequate fluids are given to replace fluid lost with diarrhea.  Cephalosporin Minimizing Adverse effects:  In addition, monitor the patient receiving IV cefazolin for the possibility of thrombophlebitis.  Provide small, frequent meals; mouth care; and ice chips to suck on if stomatitis and sore mouth are problems.  Cephalosporin Patient And Family Education Because cefazolin and the other cephalosporins are similar to penicillins, follow the same guidelines for providing patient and family education to a patient receiving penicillin. Refrain from drinking alcohol for 72 hours after drug therapy stops.  Thanks! 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