Antibacterial Drugs

Rachel R. Boersma MS, RN, CARN

Organs of the Immune SystemOrgans of the Immune System

Overview

• antibiotics: chemicals produced by living microorganisms or by laboratory synthesis

• bateriostatic: inhibit bacterial growth

• bactericidal: kill bacteria

• pathogen: disease-producing drugs or microorganisms

Immune System Refresher

• composed of

– thymus gland

– lymphatic tissue

– circulating cells

– chemical mediators

– stem cells: primitive bone marrow cells

– leukocytes: WBCs

Immune System Refresher

– lymphocytes: immune system component capable of developing into variety of other cells including—mast, basophils, macrophages, T cells

– phagocytosis: engulf and digest foreign matter

Immune System Refresher

– antigen: on cell membrane and triggers formation of antibodies

Immune System Refresher

– 4 abnormal conditions can weaken the immune system and stimulate the immune response• neoplasms• viral invasion• autoimmune disease• transplant rejection

Bacteria Physiology/Pathophysiology

• multiple routes of entry

• gram-positive bacteria

– accept positive stain often associated with respiratory and soft tissue infection

– has an easily penetrated cytoplasmic membrane

Bacteria Physiology/Pathophysiology

• gram negative bacteria– accept negative stain and often associated

with infections of GI and GU, has an additional and more complex outer membrane

• aerobic vs. anaerobic bacteria (gangrene)• culture & sensitivity – for definitive

identification of bacteria

Bacteria Physiology/Pathophysiology

• broad spectrum antibiotic – interferes with a biochemical reaction common to many organisms

• antibiotics often given in combination due to synergistic effect

• prophylaxis: prevention of potential infection

Bacteria Physiology/Pathophysiology

• resistance: bacteria adapt – control achieved by careful prescriptive practices and finishing full course of treatment

• superinfection: overgrowth of resistant bacteria, fungi, yeasts, etc.

Nursing Assessment-all antibiotics

• Before the administration of any antibiotic, it is important to ensuring the effectiveness and appropriateness of treatment to collect data regarding: – age;– a list of medications; – hypersensitivity to drugs; – hepatic, renal, and cardiac function;

Nursing Assessment – all antibiotics

– Hepatic, renal, and cardiac function; – Culture and sensitivity results; – Vital signs and bowel sounds; – Bleeding assessment (ecchymosis, bleeding

gums); – CBC, Hgb., and Hct. values.

Penicillin G – prototype of natural penicillins

• first antibiotic introduced in 1929

• IM, IV via continuous infusion

• bactericidal

Penicillin G – prototype of natural penicillins

• pharmacotherapeutics: strep infection, GC, meningococcal (high dose)

• pharmacokinetics: rapid absorption and elimination, limited penetration of blood-brain barrier

• has significant drug interactions with tetracyclines and other antibiotics when used concurrently

• other PO drugs in this group include: penicillin V, ampicillin, amoxicillin, cloxacillin

Nursing Issues – Penicillin G

• assess for any prior reactions to antibiotics

• evaluate kidney function (BUN, creatinine)

• may counteract the effect of oral contraceptives

• take po drugs on employ stomach

• take exactly as directed around the clock

Nursing Issues – Penicillin G

• take missed dose ASAP but not at the same time as next dose

• alert patient to symptoms of allergic reaction

• most common adverse effects are GI

Cephalosporins cefazolin (Kefzol)

• introduced in 1960s (3 generations)

• pharmacotherapeutics: multiple forms of infection

• IM or IV

• does not cross blood brain barrier

• interferes with cell wall synthesis

Cephalosporins cefazolin (Kefzol)

• may be bacteriostatic or bactericidal

• most common adverse effects are GI

• drug interactions with: aminoglycosides (gentamicin)

• oral anticoagulants ______________

Cephalosporins cefazolin (Kefzol)

• may cause disulfiram-like reaction (flushing, SOB, N/V, dizzy, chest pains, confusion, seizures …) when used with ethyl alcohol which may continue for 72 hours after drug is discontinued

• use with caution in anyone with impaired renal function

Fluoroquinolones – prototype – ciprofloxacin (______)

• active against both gram negative and gram positive organisms

• has prolonged postantibiotic effect• generally well tolerated however a significant

adverse reaction is arthropathy and tendon ruptures have been reported

• additional side effects include: GI and CV• oral forms as effective as IV therapy of other

antibiotics

Fluoroquinolones – prototype – ciprofloxacin (______)

• PO, IV or topical opthalmic preparation

• IV requires infusion in large vein

• take on empty stomach

• possible photosensitivity may occur

• educate pt about superinfections

Aminoglycosides – prototype - gentamicin

• useful for UTIs, gyn infections, soft tissue, etc.

• IM or IV dosing, occasionally PO for specific local effect

• may be bacteriostatic or bactericidal

• may trigger severe adverse reactions

Aminoglycosides – prototype - gentamicin

• has many serious side effects including: nephrotoxicity, ototoxicity and neuromuscular blockade consistent (often daily) monitoring required

• monitored via peak and trough levels 30 min post dose and 30 min prior to next dose

• may cause CNS and GI symptoms• multiple drug-drug interactions reported

Macrolide Antibiotics – prototype erythromycin (E-Mycin)

• same family as Z-pak (Zithromax)

• useful for those allergic to the penicillins

• good oral absorption but requires empty stomach

Macrolide Antibiotics – prototype erythromycin (E-Mycin)

• IV form is extremely irritating to veins infuse over 30-60 minutes

• GI history extremely important due to risk of antibiotic associated colitis related to clostridium overgrowth

• has significant ototoxic effects• multiple drug-drug interactions including:

benzodiazepines, carbamazepine, digoxin, oral anticoagulants…

Lincosamides – prototype clindamycin (Cleocin)

• very powerful drug effective over wide range of both aerobic and anerobic bacteria

• bactericidal in action• used for serious to life-threatening

infections caused by anaerobes, streptococci, staphylococci, etc.

• serious adverse effects: colitis• may potentiate anesthetic effects