2.  Selective toxicity: the ability to kill or suppress infecting microbes without causing injury to the host.  Classification: according to spectrum of activity (broad vs. narrow) and mechanism of action.  Bactericidal: an agent that kills bacteria  Bacteriostatic: an agent that suppresses growth of the bacteria.  Acquired resistance to antimicrobial drugs: over a period of time and exposure, an organism may become less susceptible to the drug’s action, and there fore the drug will be ineffective.

3.  Suprainfection: a new infection that appears during the course of treatment for a primary infection; this occurs more commonly in client’s receiving broad spectrum antibiotics.  4 ways to prevent antibiotic resistance: give antibiotics only when needed, use narrow spectrum agents whenever possible, save the “newer” antibiotics for situations in which older drugs are dangerous or no longer effective, minimize the administration of antibiotics to livestock.

4.  Inappropriate applications of anti-infective therapy: a common cold, bronchitis, sore throat, sinusitis, viral infections, improper dosage, omission of surgical drainage, others.  Factors to be considered when selecting antimicrobial therapy: identification of the infecting organism, drug sensitivity of the organism, and host factors (especially the host defenses).  The first rule: “match the drug with the bug”  Culture and sensitivity: if ordered, be sure to obtain prior to initiating anti-infective.

5.  Review the impact various host factors would have on the use of antimicrobials (see book).  It is imperative that antimicrobials not be discontinued prematurely. The duration of treatment for common conditions would be 7-10 days (see book for discussion).  Antibiotics may be used in combination with other antibiotics in select conditions (such as severe infections, mixed infections, etc.  Disadvantage of combination therapy: increased risk of toxic and allergic reactions, increased risk of suprainfection, drug resistance, increased cost.

6.  Anti-infectives may also be used prophalactically: client’s with valve replacements/repair, certain valvular diseases with invasive procedures that have an increased risk of infection, surgical client’s, and the use of Amantadine (an antiviral) to prevent influenza.  Misuses of anti-infectives: viral infections, treatment of fever of unknown origin, improper dosage, abscesses without I & D.

7.  Action: Bactericidal  Used primarily for gram positive infections.  Narrow and broad spectrum activity  Examples: Penicillin V (Pen-Vee K)(N), ampicillin (B), amoxicillin (B), Augmentin (B) ticar (Extended), piperacil (E).  Adverse reactions: allergic reactions (most common cause of drug allergic reaction), diarrhea, n/v, HA, sore throat, oral and vaginal infections, neurotoxicity with excessive levels, superinfection  Drug interactions: aminoglycosides (IA), BCP (IA), ACE inhibitors (increases K), probenecid (increases levels of PCN).

8.  Instruct client’s to wear medic alert bracelet if allergic to PCN’s  May be cross-sensitivity to cephalosporin's  Ticar may cause sodium overload: careful with CHF  Monitor for allergic reactions (may be immediate 2-30 minutes after administration, accelerated 1-72 hours after, or late days to weeks after.  Observe all client’s for at least 30 minutes after especially parenteral administration.

9.  Action: Bactericidal  Broad spectrum, low toxicity  Similar to PCN’s  Classifications: first, second, third, and fourth generations.  First generation: especially effective against gram positive infections. Examples: Kefzol, Keflex, Duricef.  Second generation: effective against gram positive and gram negative infections; “polymicrobial infections”. Examples: Ceclor, Cefotan, Mefoxin, Ceftin.

10.  Third generation: effective against gram negative infections. Examples: Claforan, Rocephin, Fortaz.  Fourth generation: Very broad spectrum of activity. (use of this drug not clearly identified) Example: Maxipime.  Remember: as the generations, go up in number, so does the cost!

11.  Pharmacokinetics: absorption is poor from the gi tract; preferred route parenteral.  Elimination: Kidneys, except Rocephlin which can be given safely to renal patients without a dosage reduction.  Adverse effects: well tolerated, generally safe serious AE rare. Diarrhea, pseudomembraneous colitis (rare), oral/vaginal infections, rash, puritis, thrombophlebitis, allergic reactions, bleeding.

12.  Drug interactions: calcium and Rocephlin administered together IV can form potentially fatal precipitates. The Rules: don’t reconstitute Rocephlin with calcium- containing diluents (i.e. ringers lactate), don’t mix Rocephlin with any calcium containing solution, don’t give Rocephlin and IV calcium by the same route or different routes within 48 hours of each other, if the client must receive Rocephlin and calcium, use oral calcium or IM Rocephlin.

13.  Beta-lactam antibiotics that have very broad antimicrobial spectra.  3 available: Primaxin, Merrem, Invanz, Doribax.  All given parenterally (Doribax over 1 hour for any dose)  Primaxin:  Broader antimicrobial spectrum than nearly all other antimicrobial drugs.  Very effective in treating mixed infections in which anaerobes, staph aureus, and gram-negative bacilli may all be involved.  Adverse effects: generally well tolerated. Nausea, vomiting, diarrhea, suprainfections in about 4%.

14.  Used for only serious infections because of its potential toxicity.  Indications: c-diff, MRSA, treatment of serious infections in client’s allergic to penicillin's.  Bactericidal  Effective only against gram positive bacteria  Given parenterally (slow IV infusion) because of poor systemic absorption from GI tract.  Eliminated by kidneys.  Used orally for c-diff ONLY if Flagyl is not effective.  Usual dose: 2 grams per day (depends on many factors)

15.  Adverse effects: ototoxicity, red man syndrome, red neck, red neck syndrome, thrombophlebitis.  Monitor peak(30-40) and trough levels (5-10). Peak levels: 1.5-2.5 hours after infusion; trough 30 minutes before infusion. (reduced dose if renal disease).  Red neck (syndrome): flushing (vasodilation) especially of face and neck, rash, puritis, urticaria, tachycardia, and hypotension that may be profound.  Associated with rapid (less than 1 hour) IV infusion.  Can occur as an immediate or delayed reaction.  Treatment: antihistamines (Benadryl) prior to administration, slow infusion (over minimum 60 minutes or more), and adequate dilution.

16.  Broad spectrum; gram positive and negative.  Increased numbers of resistant bacteria to the class.  Bacteriostatic  Therapeutic uses: rarely drugs of first choice; used for rocky mountain spotted fever, typhus fever, chlamydia, brucellosis, cholera, mycoplasma pneumonia, Lyme disease, anthrax, H.pylori, acne, periodontal disease.  Pharmacokinetics: orally effective but absorption varies among drugs.

17.  Tetracyclines are divided into 3 groups: short acting, intermediate acting, and long acting. Examples: SA: tetracycline (Sumycin), IA: Declomycin, LA: doxycycline (Vibramycin), minocycline (Minocin).  Tetracycline absorption can be influenced by the presence of food in the stomach, calcium (dairy product, TUMS), iron. Be sure to check before administration.  Adverse effects: GI irritation, esophageal irritation, tooth discoloration, superinfection, photosensitivity, vestibular toxicity, AAPMC, fungal infections.

18.  Broad spectrum/bacteriostatic  Erythromycin is prototype. Others include: Biaxin, Zithromax.  Relatively safe.  Uses: legionnaires disease, alternative for PCN allergies, whooping cough, pneumonia, respiratory tract infections (Zithromax and Biaxin), chlamydia (Zithromax).  Adverse effects: GI distress (especially Erythromycin), liver injury, superinfection, thrombophlebitis, taste distortion (Biaxin)  Be sure to check on administration concerns of each drug (i.e. the rate of Zithromax absorption is reduced if given with aluminum and magnesium antacids)

19.  Very important drug because it has activity against multidrug-resistant gram positive pathogens, including VRE and MRSA.  To delay drug resistance, it should generally be reserved for infections caused by VRE or MRSA.  Effective against gram positive bacteria.  Adverse effects: well tolerated; diarrhea, nausea, headache.  Given orally or intravenously. Can be taken with or without food. IV Zyvox should not be combined with additives or other drugs.

20.  Tetracycline's are contraindicated in pregnant women and in children under 8 years of age.  Advise patients to take oral tetracycline's on an empty stomach (1 hour before meals or 2 hours after) and with a full glass of water.  Avoid dairy products, calcium, iron, magnesium laxative, and most antacids with tetracycline's.  Warn clients about photosensitivity, fungal overgrowth.  Erythromycin: take on an empty stomach with a full glass of water. However, if GI upset occurs, administration may be done with meals.

21.  Narrow spectrum/ bactericidal/ effective primarily against aerobic gram-negative bacteria.  The aminoglycosides can cause serious injury to the inner ear and the kidneys. Because of these toxicities, indications for these drugs are limited; primary indication is serious infections due to aerobic gram negative bacteria.  Must be administered parenterally because they are not absorbed if administered orally.  Most common agents: gentamycin, tobramycin, amikacin.  Oral therapy: prophalactically to suppress bacterial growth in the bowel/ topical for eyes, ears and skin.

22.  Dosages are individualized according to patients serum levels and renal function tests.  Adverse effects: ototoxicity (related to high trough levels and usually reversible), nephrotoxicity (related to high trough levels and usually reversible), hypersensitivity reactions.  Penicillin+aminoglycoside(given together or mixed together) = inactivation of amino.  Once a day dosing actually safer.  Serum drug levels: Gent peak: 4-10, trough <2.

23.  Primarily used for UTI’s.  Bacteriostatic  Adverse effects: crystalluria, Stevens- Johnson Syndrome.  Stevens-Johnson syndrome: a rare reaction with a mortality rate of 25%. Symptoms: widespread lesions of the skin and mucous membranes, fever, malaise, toxemia. 

25.  Broad spectrum/ IV or PO administration.  All can be administered orally and are effective alternatives for IV antimicrobial therapy.  Examples: Cipro, Levaquin, Tequin.  Therapeutic uses: respiratory tract infections, UTI’s, skin, bone and joint infections, Anthrax.  Adverse effects (Cipro): GI reactions, dizziness, HA, RLN, candida, rupture of the Achilles tendon. CNS disturbances (confusion, psychosis, visual disturbances) esp. in elderly.  Many drug-drug interactions.  Absorption of Cipro and Levaquin PO reduced if ingested with aluminum or magnesium antacids, iron, zinc, Carafate, milk, and other dairy products.

26.  Metronidazole (Flagyl©): used for protozoal infections and some anaerobic bacteria.  Uses: infections of the CNS, abdominal organs, bones and joints, skin and soft tissues and GU tract. Drug of choice for c- diff. Also used in combination therapy with tetracycline and pepto for H. pylori.  IV administration: preparation should not be refrigerated as cooling may cause precipitate to form, must be given slowly (over 1 hour).