Antibiotic Drugs Flashcards
What are antibacterial drugs?
Antibacterial drugs are derived from bacteria or molds or are synthesized de novo. Technically, “antibiotic” refers only to antimicrobials derived from bacteria or molds but is often (including in THE MANUAL) used synonymously with “antibacterial drug.”
What are Bacteria?
- Also known as prokaryotes which are single-celled organisms that lack a true nucleus and nuclear membrane
- It has a cell wall, that determines its shape
- Hans Christian Gram devised a method to classify bacteria using the Gram-stain method
How to differentiate Antiseptics and Disinfectants?
Antiseptic: / Disinfectants:
where it can be used: Living tissue / Nonliving objects
potency: Lower / Higher
Activity against organism: Primarily inhibits growth (Bacteriostatic) / Kills (Bactericidal)
How do Antibacterial drugs?
- Antibacterial drugs penetrate the bacterial cell wall and have an affinity for the bacteria’s binding sites
- The more time the drug remains bound, the longer the effect of the antibacterial action
- MEC (Minimum Effective Concentration) – minimum amount of antibacterial drug to halt the growth of microorganisms
What are the 5 mechanisms of Antibacterial drugs’ action?
Five Mechanisms of Antibacterial Action:
1) inhibition of bacterial cell-wall synthesis;
2) alteration of membrane permeability;
3) inhibition of protein synthesis;
4) inhibition of the synthesis of bacterial RNA and DNA;
5) interference with metabolism within the cell
How do antibacterial drugs effects bacteria?
- When bacteria is sensitive to the drug = the pathogen can be inhibited or destroyed
- When bacteria is resistant to the drug = the pathogen will continue to grow despite administration
- Types of Resistance:
1) inherent – occurs without previous exposure to the drug;
2) acquired – caused by prior exposure to the antibacterial
- Types of Resistance:
General Adverse Reactions to Antibacterial Drugs
Type: - Constraints
Allergy or hypersensitivity
- Allergic reactions to drugs may be mild or severe. Examples of mild reactions are rash, pruritus, and hives. An example of a severe response is anaphylactic shock, which results in vascular collapse, laryngeal edema, bronchospasm, and cardiac arrest. A severe allergic reaction generally occurs within 20 minutes, and shortness of breath is often the first symptom of anaphylaxis. Mild allergic reaction is treated with an antihistamine, whereas anaphylaxis requires treatment with epinephrine, bronchodilators, and antihistamines.
Superinfection
- Superinfection is a secondary infection that occurs when the normal microbial flora of the body is disturbed during antibiotic therapy. Superinfections can occur in the mouth, respiratory tract, intestine, genitourinary tract, and skin. Fungal infections frequently result in superinfections, although bacterial organisms (e.g., Proteus, Pseudomonas, Staphylococcus) may be the offending microorganisms. Superinfections rarely develop when the drug is administered for less than 1 week, and they occur more commonly with the use of broad-spectrum antibiotics. For fungal infection of the mouth, nystatin is frequently used.
Organ toxicity
- The liver and kidneys are involved in drug metabolism and excretion, and antibacterials may result in damage to these organs. For example, aminoglycosides can be nephrotoxic and ototoxic.
What are the Antibiotic Combinations?
- ADDITIVE EFFECT - equal to the sum of the effects of two antibiotics
- POTENTIATIVE EFFECT – occurs when one antibiotic increases the effectiveness of the 2nd drug
- ANTAGONISTIC EFFECT – when two drugs are used together, the desired effect may be greatly reduced
How to differentiate between Narrow and broad spectrum Antibacterial drugs?
- NARROW SPECTRUM
– primarily effective against one type of organism (selective)
– Targetted treatment for documented infections - BROAD SPECTRUM
– effective against gram-positive and gram-negative organisms
– Empiric treatment of non-documented infections
– Rish for selection of resistance
What are Empiric therapy, Definitive Therapy, Subtherapeutic, and Superinfection?
- EMPIRIC THERAPY – when a drug selected is known to be the best drug that can kill the MO
- DEFINITIVE THERAPY – once the MO is identified in the lab, the antibiotic therapy is tailored by using the most narrow-spectrum, least toxic drug based on C&S results
- SUBTHERAPEUTIC – when signs and symptoms do not improve
- SUPERINFECTION – occurs when the antibiotics reduce or completely eliminate the normal bacterial flora
How would health professionals select antimicrobials?
Laboratory testing is performed on body fluids (blood, urine, sputum, wound drainage) to determine the MOs causing the infection:
- Gram stain – aspirate of the body fluid is examined under the microscope
- Culture – aspirated is applied to a medium where they are grown for several days - Sensitivity – used for organisms where resistance is common, to test for sensitivity of the organisms to various antimicrobials
What are the different factors the health professionals would consider for the patient or host?
1.) Immune Systems
2.) Site of Injection
3.) Age
4.) Pregnancy
How to use prophylactic drugs?
- Indications:
1. Prevention of infection for clients with GIT, Cardio, Orthopedic or Gynecologic surgeries
2. Prevention of STI’s following sexual exposure - Limit prophylactic use to patients with;
1. Prosthetic heart valves
2. Recurring urinary tract infections
What could be some preventive measures for the nurse to do to protect the patient and the nurse?
- Perform hand hygiene before and after client contact
- Recognize invasive procedures that increase the chance of infection
- Encourage health measures by maintaining up-to-date immunization status
- Use infection control procedures to prevent transmission
- Evaluate the effectiveness of the treatment
What are some drugs used for affecting Bacterial cell walls?
1.Penicillin
2.Cephalosporins
3.Other Inhibitors
What are beta-lactam Antibiotics?
- The drugs contain beta-lactam rings in their structures that include: penicillin, cephalosporins, carbapenems and monobactams that inhibit the synthesis of bacterial peptidoglycan cell wall
- Some bacterial strains produce an enzyme, BETALACTAMASE which provides resistance by destroying the beta-lactam ring in the drugs
- Thus beta-lactam drugs need an additional drug called, BETA-LACTAMASE INHIBITOR to make the drug more powerful than those MOs
facts about Penicillin
- Drug of choice for gram-positive cocci such as Streptococcus pneumoniae, viridans, and pyogenes
- Drug of choice for meningitis caused by gram-negative cocci, Neisseria meningitides
- Drug of choice for syphilis caused by Spirochete treponema pallidum
- Extended Spectrum is effective against Pseudomonas, Enterobacter, proteus, Bacteroides, klebsiella
- Prophylaxis against bacterial endocarditis prior to dental and other procedures
What are some complications with using Penicillin? What are your nursing interventions?
- Allergies/anaphylaxis
- Interview clients for prior allergies.
- Advise clients to wear an allergy identification bracelet.
- Observe clients for 30 min following the administration of parenteral penicillin. - Renal Impairment
- Monitor kidney function.
- Monitor I&O. - Hyperkalemia/dysrhythmias (high doses of penicillin G potassium) and Hypernatremia (IV ticarcillin)
- Monitor the cardiac status and electrolyte levels.
what are some contraindications and precautions before using Penicillin
- Penicillins are contraindicated for clients who have a severe history of allergies
- Use cautiously in clients who have or are at risk for kidney dysfunction
- Penicillin Skin Test is done before administration
- Pregnancy Category B
What to expect when administering penicillin?
= Most as excreted via the kidneys thus assessment of BUN and Creatinine for the renal function is important
= Common adverse reaction includes: hypersensitivity and superinfection (occurrence of secondary infection when the flora of the body are disturbed); GI Distress (anorexia, N&V, diarrhea)
= W/O for interactions with potassium supplements and use of aminoglycosides
= W/O Clostridium difficile- associated diarrhea (superinfection)
= Teach patients to take the entire prescribed penicillin product to prevent drug resistance
What are Cephalosporins and what are the different generations of cephalosporins?
From a fungus discovered in seawater, its molecules are chemically altered and semi-synthetic medications are produced
Generation and Activity
First - Effective mostly against gram-positive bacteria (streptococci and most staphylococci) and some gram-negative bacteria (Escherichia coli and species of Klebsiella, Proteus, Salmonella, and Shigella)
Second - Same effectiveness as the first generation but with a broader spectrum against other gram-negative bacteria such as Haemophilus influenza, Neisseria gonorrhoeae and N. meningitides, Enterobacter species, and several anaerobic organisms
Third - Same effectiveness as first and second generations and also effective against gram-negative bacteria (Pseudomonas aeruginosa and Serratia and Acinetobacter species) but with increased resistance to destruction by beta-lactamases
Fourth - Similar to third-generation drugs and highly resistant to most beta-lactamase bacteria with broad-spectrum antibacterial activity and good penetration to cerebrospinal fluid; effective against E. coli, P. aeruginosa, and Klebsiella, Proteus, and Streptococcus species, and certain staphylococci
Fifth - Similar characteristics of third and fourth generations, also broad spectrum, and the only cephalosporins effective against methicillin-resistant Staphylococcus aureus (MRSA)
The different drugs based on the generation of cephalosporins
First generation:
IV: Cefazolin, Cephradine
PO: Cefadroxil, Cephalexin, Cephradine
Second generation:
IV: Cefoxitin, Cefuroxime, Cefotetan, Locacarbel
PO: Cefactor, Cefuroxime Axetil, cefprozil
Third generation:
IV: Cefotaxime, Ceftizoxime, Ceftriaxone, Ceftazidime
PO: Cefpodoxime, Ceftibuten, Cefdinir
Fourth generation:
IV: Cefepime
Fifth generation:
IV: Ceftaroline
Cephalosporins drug interactions with other drugs
- Ethanol (alcohol)
Mechanism: Accumulation of acetaldehyde metabolite of ethanol
Result: Acute alcohol intolerance (disulfiram-like reaction) after drinking alcoholic
beverages within 72 hr of taking cefotetan. Symptoms include stomach cramps, nausea, vomiting, diaphoresis, pruritus, headache, and hypotension. - Antacids, iron
Mechanism: Decreased absorption of certain oral cephalosporins (cefdinir, cefditoren)
Result: Decreased effectiveness of the drug - probenecid
Mechanism: Decreased renal excretion
Result: Increased cephalosporin levels - Oral contraceptives (OCs)
Mechanism: Enhanced OC metabolism
Result: Increased risk for unintended pregnancy
What are some complications with using Cephalosporins? What are your nursing interventions?
A.) Allergic/hypersensitivity/anaphylaxis
› If indications of allergy appear (urticaria, rash, hypotension, and/or dyspnea) stop cephalosporin immediately, and notify the provider.
A.2.)Possible cross-sensitivity to penicillin
› Question the client carefully regarding past history of allergy to penicillin or another cephalosporin, and notify the provider if present.
B.) Bleeding tendencies with the use of cefotetan and ceftriaxone
› Avoid use in clients who have bleeding disorders and those taking anticoagulants.
› Observe clients for signs of bleeding.
› Monitor prothrombin time and bleeding time. Abnormal levels can require discontinuation of the medication.
› Administer parenteral vitamin K.
C.) Thrombophlebitis with IV infusion
› Rotate injection sites.
› Administer as a diluted intermittent infusion or, if a bolus dose is prescribed, administer slowly over 3 to 5 min and in a dilute solution.
D.) Pain with IM injection
› Administer IM injection deep in large muscle mass.
E.)Antibiotic-associated pseudomembranous colitis
› Observe clients for diarrhea and notify the provider.
› Medication should be discontinued.
Drug Interactions of Cephalosporins and nursing interventions and nursing administration
A.) Disulfiram reaction (intolerance to alcohol) occurs with the combined use of cefotetan, cefazolin, cefoperazone, and alcohol
= Instruct clients not to consume alcohol while taking these cephalosporins
B.) Probenecid delays renal excretion
= Monitor I&O
Nursing administration:
* Instruct clients to complete the prescribed course of therapy, even though symptoms can resolve before the full course of antimicrobial treatment is completed.
* Advise clients to take oral cephalosporins with food.
* Instruct clients to store oral cephalosporin suspensions in a refrigerator.
What is Carbapenemss?
- Have the broadest antibacterial actions of any antibiotics; Bactericidal and inhibit cell wall synthesis and are often reserved for complicated body cavity and connective tissue infections
- W/O for drug-induced seizure activity
the complications and interactions of Carbapenems
A.) Allergy/hypersensitivity - Possible cross-sensitivity to penicillin or cephalosporins
> Monitor clients for indications of allergic reactions, such as rashes or pruritus.
> Question clients carefully regarding past history of allergy to penicillin or other cephalosporin and notify the provider if present.
B.) Gastrointestinal symptoms (nausea, vomiting, diarrhea)
> Observe clients for manifestations and notify the provider if they occur.
> Monitor I&O.
C.) Suprainfection
> Monitor for indications of colitis (diarrhea, oral thrush, and/or vaginal yeast infection).
Interactions
MEDICATION/FOOD INTERACTIONS
> Imipenem-cilastatin can reduce blood levels of valproic acid (Depakote). Breakthrough seizures are possible.
NURSING INTERVENTIONS/CLIENT EDUCATION
> Avoid using together. If concurrent use is unavoidable, monitor for increased seizure activity.
