Antibiotics

Question 1

Prophylactic Therapy

Answer 1

• Antibiotics taken before an anticipated exposure to an infectious organism in an effort to prevent infection
• Before GI surgery
• Before arthroplasty
• Prior to dental procedures in certain populations

Question 2

Empiric Therapy

Answer 2

• Starting antibiotic therapy prior to identification of organism
• Decreased the risk of life-threatening illness and/or complications
• Time-consuming to identify offending pathogen
• Broad spectrum antibiotic
• Cultures need to be obtained prior to starting therapy

Question 3

Definitive Therapy

Answer 3

Antibiotic based on the known results of C & S testing that has identified pathogen causing infection

Question 4

General Principles of Antibiotics

Answer 4

• Assess for therapeutic efficacy -improved symptoms, decreased WBC count
• Without improvement –subtherapeutic therapy
• WHY?Incorrect drug, route, dose, adherence, bacterial resistance, drug drug or drug food interaction

Question 5

Antibiotic toxicity

Answer 5

• Occurs when serum levels are too high

* With evidence of allergic reaction –rash, pruritus, joint pain, hives, fever, chills, dyspnea, wheezing

Question 6

Superinfection

Answer 6

occur When the body’s normal flora Is reduced or eliminated by antibiotics

Question 7

Examples of superinfection

Answer 7

1. Yeast Infections –Candida–oral (thrush), vaginal,skin folds
2. Secondary Infections
   • Secondary microbial infection (bacterial often follows viral) occurring in addition to an earlier infection; usually because of a weakened immune system due to the earlier infection

Question 8

Aminoglycoside Antibiotics Mechanism of Action and Therapeutic Effects

Answer 8

Aminoglycosides bind to ribosomes and thereby prevent protein synthesis in bacteria. Specifically, they accomplish this by binding to a structure known as the 30S ribosomal subunit. Protein synthesis is then disrupted by genetic misreadings of messenger RNA (mRNA) molecules, leading to cell death. The toxicity associated with aminoglycosides normally limits their use to treatment of serious gram-negative infections and specific conditions involving gram-positive cocci. Aminoglycosides are also used for prophylaxis in procedures that place patients at high risk for enterococcal infections, such as procedures involving the gastrointestinal (GI) tract and in patients who are undergoing surgery and have a history of valvular heart disease.

Question 9

Aminoglycoside Antibiotics Contraindications/Precautions

Answer 9

Drug allergy, pregnancy, and lactation

Question 10

Aminoglycoside Antibiotics Drug Interactions

Answer 10

Increased risk for nephrotoxicity occurs with concurrent use of other nephrotoxic drugs, such as vancomycin, cyclosporine, and amphotericin B. Increased risk for ototoxicity occurs with concurrent use of loop diuretics. In addition, aminoglycosides can potentiate warfarin toxicity.

Question 11

Aminoglycoside Antibiotics Adverse Effects

Answer 11

Effects may include nephrotoxicity and ototoxicity as well as headache, paresthesia, dizziness, vertigo, skin rash, fever, overgrowth of nonsusceptible organisms, and neuromuscular paralysis (rare and reversible).

Question 12

Aminoglycoside Antibiotics Nursing Implications

Answer 12

• Assess allergies prior to administration, and assess for an allergic reaction after administration.
• Assess baseline hearing and renal function.
• Monitor for signs and symptoms of nephrotoxicity and ototoxicity.
• Draw a trough blood sample at least 18 hours after completion of the medication dose (closer to 24 hours afterward for renally impaired patients). The therapeutic goal is a trough level at or below 1 mcg/mL. Trough levels greater than 2 mcg/mL are associated with greater risk for both ototoxicity and nephrotoxicity.
• Maintain adequate hydration by encouraging up to 3000 mL/day.
• Give intramuscular injections deeply and slowly to minimize discomfort.
• Administer intravenous infusions over a period of 30 to 60 minutes in adults and over 60 to 120 minutes in infants and children.

Question 13

Aminoglycoside Antibiotics Patient Education

Answer 13

• Report immediately to the health care provider any changes in hearing, ringing in the ears (tinnitus), or full feeling in the ears. Nausea, vomiting with motion, ataxia, nystagmus, or dizziness should also be reported immediately.
• Consumption of yogurt or buttermilk may help to prevent antibiotic-induced superinfections.
• Report any signs or symptoms of superinfection, such as diarrhea, vaginal discharge, stomatitis, or glossitis, as well as black hairy tongue, loose and foul-smelling stools, or cough.
• Increase fluid intake to up to 3000 mL/day unless contraindicated.

Question 14

β-Lactam Antibiotics (Penicillins and Cephalosporins) Mechanism of Action and Therapeutic Effects

Answer 14

Penicillin and cephalosporin antibiotics are structurally and pharmacologically similar. Both contain a beta (β)-lactam ring, are bactericidal, work by interfering with bacterial cell wall synthesis, and have a broad spectrum of activity. The penicillins are a very large group of chemically related antibiotics derived from a mold fungus often seen on bread and fruit. Cephalosporins are semisynthetic antibiotic derivatives also derived from mold. Modifications of the basic chemical structure have given rise to four generations of cephalosporins. Depending on the generation, these drugs may be active against gram-positive, gram-negative, or anaerobic bacteria. In general, the level of gram-negative coverage increases with each successive generation.

Question 15

β-Lactam Antibiotics (Penicillins and Cephalosporins) Contraindications/Precautions

Answer 15

Drug allergy. Cross-sensitivity is probably the result of structural similarity, so penicillins should be used cautiously in patients allergic to a cephalosporin and vice versa

Question 16

β-Lactam Antibiotics (Penicillins and Cephalosporins) Drug Interactions

Answer 16

Increased effects occur when combined with aminoglycosides and other penicillins. Prolonged effects occur when combined with nonsteroidal antiinflammatory drugs. Decreased effects occur when combined with neomycin and rifampin (penicillins). Decreased effectiveness of oral contraceptives occurs with penicillins. Enhanced anticoagulant effects of warfarin occur with penicillins. Risk for hyperkalemia occurs when penicillins are given with potassium supplements. Increased alcohol intolerance occurs when cephalosporins are given with disulfiram.

Question 17

β-Lactam Antibiotics (Penicillins and Cephalosporins) Adverse Effects

Answer 17

Central nervous system effects include lethargy, hallucinations, anxiety, depression, twitching, coma, and convulsions. Gastrointestinal system effects include nausea, vomiting, diarrhea, increased levels of aspartate aminotransferase and alanine transaminase, abdominal pain, and colitis. Hematologic system effects include anemia, increased bleeding time, bone marrow depression, and granulocytopenia. Metabolic system effects include hyperkalemia, hypokalemia, and alkalosis. Miscellaneous effects include taste alterations; soreness in mouth; dark, discoloured, or sore tongue; hives; and rash.

Question 18

β-Lactam Antibiotics (Penicillins and Cephalosporins) Implications

Answer 18

• Assess allergies prior to administration and continue to monitor for hypersensitivity reactions after the assessment phase because immediate reactions may occur within 30 minutes; accelerated reactions occur within 1 to 72 hours; and delayed responses may occur after 72 hours.
• Administer around the clock to maintain effective blood levels.
• Administer oral penicillins with at least 180 mL of water (versus juice) because of interaction between the drug’s antibacterial action and acidic juices.
• Administer oral cephalosporins with food to decrease gastrointestinal upset, even though this will delay absorption. Alcohol and alcohol-containing products should be avoided because of the Antabuse-like reactions that are associated with some of the cephalosporins.

Question 19

β-Lactam Antibiotics (Penicillins and Cephalosporins) Patient Education

Answer 19

• For penicillins: Take the drugs exactly as prescribed and for the full duration, with spacing of doses at regularly scheduled intervals. Take them with water. Oral dosage forms should not be taken with caffeine, citrus fruit, cola beverages, fruit juices, or tomato juice because they will inactive the drug.
• For cephalosporins: It is important to eat dairy products to minimize superinfections. Avoid over-the-counter liquid cold products that contain alcohol so as to avoid an Antabuse-like reaction (with some of the cephalosporins).
• For cephalosporins: Report diarrhea, flulike symptoms, blistering or peeling of the skin, hearing loss, breathing difficulty, or seizures to the health care provider immediately. Report immediately the occurrence of foul-smelling, loose, frequent stools or bloody stools.
• The signs and symptoms of superinfection include fever, black hairy tongue, stomatitis, loose or foul-smelling stools, vaginal discharge, or cough. Contact the health care provider should any of these effects occur.
• Consume yogurt, buttermilk, or kefir to help prevent superinfections such as the occurrence of vaginal yeast infections.
• Oral contraceptives interact with the antibiotic, so use other forms of contraception.

Question 20

Sulfonamide Antibiotics Mechanism of Action and Therapeutic Effects

Answer 20

Sulfonamides inhibit the growth of susceptible bacteria by preventing bacterial synthesis of folic acid. Specifically, sulfonamides are structural analogs of paraaminobenzoic acid (PABA), a substance required by many microorganisms for the production of folic acid. Therefore, these drugs prevent the growth of microorganisms by inhibiting the production of folic acid in bacterial cells through competition with PABA. Host cells and microorganisms that require exogenous folic acid (not synthesized by the bacterium itself) are not affected by sulfonamide antibiotics. Sulfonamides have a broad spectrum of antibacterial activity, including both gram-positive and gram-negative organisms. These antibiotics achieve high concentrations in the kidneys, through which they are eliminated. In particular, co-trimoxazole (SMX-TMP) is commonly used in the treatment of urinary tract infections. This combination drug is also used for respiratory tract infections, opportunistic infection prophylaxis, and treatment in patients affected by the human immunodeficiency virus (HIV).

Question 21

Sulfonamide Antibiotics Contraindications/Precautions

Answer 21

Drug allergy to sulfonamides or chemically related drugs, such as sulfonylureas and thiazide and loop diuretics; allergy to carbonic anhydrase inhibitors; pregnancy at term; infants younger than 2 months of age

Question 22

Sulfonamide Antibiotics Drug Interactions

Answer 22

Sulfonamides can potentiate the hypoglycemic effects of sulfonylureas in diabetes, the toxic effects of phenytoin, and the anticoagulant effects of warfarin. Sulfonamides may also inhibit the immunosuppressant effects of cyclosporine in transplant patients, and can also increase the likelihood of cyclosporine-induced nephrotoxicity.

Question 23

Sulfonamide Antibiotics Adverse Effects

Answer 23

Hematological system effects include agranulocytosis, aplastic anemia, hemolytic anemia, and thrombocytopenia. Gastrointestinal system effects include nausea and vomiting, pancreatitis, and diarrhea. Integumentary system effects include epidermal necrolysis, exfoliative dermatitis, Stevens-Johnson syndrome, and photosensitivity. Miscellaneous adverse effects include convulsions, crystalluria, toxic nephrosis, headache, peripheral neuritis, and urticaria.

Question 24

Sulfonamide Antibiotics Nursing Implications

Answer 24

• Assess allergies prior to administering, and assess for allergic reaction after administering.
• Assess renal function and blood counts prior to and during therapy.
• Perform thorough skin assessment during drug therapy, monitoring for adverse cutaneous reactions.

Question 25

Sulfonamide Antibiotics Patient Education

Answer 25

• Take as directed, with plenty of fluids (2000 to 3000 mL/24 hours) to prevent drug-related crystalluria.
• Take oral dosage forms with food to minimize gastrointestinal upset.
• Report any of the following signs and symptoms to the health care provider immediately: worsening abdominal cramps, stomach pain, diarrhea, blood in the urine, severe or worsening rash, shortness of breath, and fever.