Anti-Infective Agents

Antibiotics/antimicrobials primary goal

destroy or inhibit growth of bacteria or fungi while not harming host tissue

Antibiotics/antimicrobials - bactericidal

destroy growth of bacteria or fungi

Antibiotics/antimicrobials - bacteriostatic

inhibit growth of bacteria or fungi

General antibiotic therapy guidelines

HCP picks the best antibiotic

Empiric therapy

targets most likely pathogen

Type of microorganisms by most likely type of infection

gram positive/negative, aerobic/anaerobic

Severe cases of infection

culture and sensitivity - first collect specimens for C&S (blood, urine, wound), next begin broad-spectrum antibiotics (based on tentative infection ID), when C&S results return (several days - indicate which antibiotic will kill bacteria), last change to specific antibiotic

Ensure appropriate dosage/duration

if dose is too small and/or too short a duration, may result in therapy failure and/or drug resistance to therapy

Monitor therapeutic levels by measuring…

peak and trough of drug

Peak

highest blood level drawn within 30 min after dose is completed

Trough

lowest blood level drawn within 30 min before next dose is initiated

Antibiotics - nursing assessments

drug allergies, renal, liver and cardiac function, electrolytes and blood chemistries, thorough patient health history and comorbidities, potential drug-drug, drug-food interactions, conditions that may indicate contraindications/cautious use (kidney dysfunction, liver dysfunction, immune status)

Antibiotics - safety measures

check the name of the medication carefully (many drugs should alike or have similar spellings), all oral antibiotics absorb better if taken with at least 6-8 ounces of water, each class of antibiotics has specific SE/ADR/drug interactions to assess and monitor, if giving a parenteral antibiotic injection always monitor 15-20 min after for anaphylactic reactions, monitor for therapeutic effects (clinical improvement), monitor for SE/ADR

General adverse reactions/side effects of antibiotics

determine previous allergy/adverse reactions before administration, ask what kind of reaction

Common side effects of antibiotics

nausea, vomiting, diarrhea

Adverse reactions to antibiotics include…

clostridium difficile, superinfection, allergic hypersensitivity reactions, anaphylaxis

Clostridium difficile (C. diff)

may develop after taking multiple courses (extended duration) of strong antibiotics (persistent, watery stool) - contact isolation

Superinfection

eradicate/reduce normal flora growth, Candida (yeast) endogenous to body - S&S include fever, perineal, itching, cough, lethargy or any unusual discharge - treat with antifungals

Allergic hypersensitivity reactions

S&S include rash, fever, chills, urticaria, pruritus, generalized erythema - stop taking drug and notify HCP - treat with antihistamines, steroids

Anaphylaxis

911 - stop taking drug, go to ER - S&S include rash, urticaria, erythema, laryngeal edema, dyspnea, SOB, wheezing, hypotension, tachycardia, anxiety, restlessness - treat with airway maintenance, epinephrine, antihistamines, corticosteroids

Antibiomania

a rare antibiotic side effect

Sulfonamides

anti-metabolites that inhibit DNA, RNA and protein productions - often combined with other antibiotics (Bactrim, Septra, co-trimoxazole (SMX-TMP)) - given for UTI, Otitis Media, prophylaxis for Pneumocystis carinii

Patient teaching for sulfonamides

force fluids (2-3 L/24 hr), assess baseline RBCs and periodically thereafter, may cause photosensitivity (wear long sleeves, stay out of sun), take oral doses with food

Penicillins

beta-lactam cell wall inhibitors that bind to and inactivate penicillin-binding proteins on the bacterial cell wall - many drug-drug interactions (increase effects of warfarin) - monitor patients taking parenteral injections for allergic reactions for at least 30 min after giving

Amoxicillin (a penicillin)

broad spectrum, Otitis media, sinusitis, pneumonia

Patient teaching on penicillins

take oral doses with water, not juice - acidic fluids may nullify drug’s antibacterial action - use second form of contraception if on oral contraceptives

Cross sensitivity often seen with…

penicillin and cephalosporins

Cephalosporins

3rd generation beta-lactam cell wall inhibitors (ceftriaxone (Rocephin)) - may cause a disulfiram-lime (Antabuse) reaction (severe N&V) when taken with alcohol - monitor patients taking parenteral injections for allergic reactions for at least 30 min after giving

Patient teaching for cephalosporins

take with food to decrease GI upset - avoid alcohol (causes severe GI upset - N&V)

Macrolides

inhibits protein synthesis - highly protein bound, may cause severe interactions with other protein-bound drugs - absorption of oral erythromycin enhanced when taken on an empty stomach

Azithromycin (Zithromax) (a macrolide)

strep throat, URI, skin infections, uncomplicated Chlamydia

Patient teaching on macrolides

take on an empty stomach unless you have severe GI upset with drug, then with meal or snack - SE include GI upset, abdominal pain

Tetracyclines

inhibit protein synthesis - do not use in children under age 8 or in pregnant/lactating women - the drug binds to the calcium in the teeth and causes tooth discoloration

Doxycycline (Doryx, Vibramycin) (tetracycline)

staph, strep, Neisseria gonorrhoeae, approved for malaria prophylaxis, chlamydia, acne, Lyme disease

Patient teaching for tetracyclines

avoid with milk and dairy products, iron preparations, and antacids (causes chelation and drug-binding) - take at least 2 hours aparts - take all medications with 6-8 ounces of fluid, preferably water - may cause photosensitivity (wear long sleeves, stay out of sun)

Nitrofurans

interfere with bacterial protein and cell wall synthesis - nitrofurantoin (Macrobid, Macrodantin, Furadantin), treats lower UTIs (esp E. coli - med concentrates in urine, not blood) - avoid with kidney/liver disease

Common side effects on nitrofurans

HA, dizziness, gas, upset stomach, N/V/D, can darken urine

Patient teaching for nitrofurans

take with food, can darken urine (harmless SE), do not take with antacids *at least 2 hours apart)

Fluoroquinolones

DNA inhibitors - many drug-drug reactions - black box warnings (increased risk of tendonitis and tendon (Achilles) rupture, peripheral neuropathy, suicidal ideation)

Ciprofloxacin (Cipro) (fluoroquinolone)

skin and bone infections, UTI, bacterial prostatitis, lower resp infection, pneumonia, anthrax

Patient teaching for fluoroquinolones

avoid taking with antacids (decreases absorption) - 2 hours apart, notify HCP if tendonitis, muscle weakness or thoughts of suicide occur

Enrofloxacin (Baytril) (fluoroquinolone)

not for humans (retinotoxic to cats - sudden blindness)

Aminoglycosides

inhibit protein synthesis - severe SE/ADRs include ototoxicity (temporary or permanent hearing loss) and nephrotoxicity (reduced renal function)

Gentamycin (aminoglycoside)

DOC = enterobacter, E. coli, proteus, pseudomonas

Aminoglycoside monitoring includes…

peak and trough levels every 5-7 days during therapy, serum BUN and creatinine levels at least every 3 days, patient hearing

Patient teaching for aminoglycosides

force fluids, notify nurse/HCP for dizziness, tinnitus, balance problems, hearing loss, feeling of fullness in ears, use contraception (unsafe for fetus)

Oxazolidinones

synthetic, broad-spectrum antibiotic class - inhibits bacterial protein synthesis at the 50S ribosomal subunit - linezolid (Zyvox), tedizolid (Sivextro) - prescription for superbugs (MRSA, pneumonia, sepsis) - avoid foods with tyramine (can cause hypertensive crisis)

Oxazolidinones serious side effects (especially on long term therapy)

bone marrow suppression (monitor blood counts, observe for fatigue, bleeding, infection), peripheral and optic neuropathy (monitor vision, report visual changes, paresthesias), serotonin syndrome (monitor for fever, tachycardia, agitation, tremors)

Patient teaching for oxazolidinones

instruct patient to report severe fatigue, bleeding, infection, unusual visual changes, paresthesias, numbness, tingling in extremities, fever, fast heartbeat, agitation, tremors, to avoid foods including tyramine (aged cheeses, red wine, cured meats, foods with cultures or fermented foods)

Glycopeptides (vancomycin - Vancocin)

inhibit bacterial cell wall synthesis, DOC for MRSA/gram+, infuse over at least 60 mins (rapid infusions may cause hypotension), monitor peak/trough levels

Glycopeptides (vancomycin - Vancocin) severe side effects

nephrotoxicity - monitor serum BUN and creatinine - may cause Red Man Syndrome

Patient teaching for glycopeptides (vancomycin)

force fluids (2L/24 hrs), avoid NSAIDs (potential for kidney damage), avoid OTC anti-diarrheal medication (discuss with HCP first), notify HCP for dizziness, tinnitus, balance problems, hearing loss, feeling of fullness in ears

Red man syndrome - vancomycin ADR

flushing/itching of head, neck, face, upper trunk - antihistamine reduces these effects (pretreat with diphenhydramine) - ensure hydration (at least 2L/24 hrs if not contraindicated to prevent nephrotoxicity)

Nursing considerations/patient teaching for antibiotics

take full course of medication (do not stop when you feel better, share meds, save meds and take in evenly spaced doses), drug-drug and food-drug interactions, N/V/D common SE for all, stop drug and notify HCP if allergic reaction, stop drug and call 911 if anaphylaxis, for potential nephrotoxicity (monitor BUN/creatinine, I&O/daily weights, force fluids)

Ciprofloxacin, clindamycin and/or penicillins + alcohol =

can increase severity of antibiotic side effects

Amoxicillin, doxycycline + alcohol =

delays the antibiotic from taking effect

All antibiotics + alcohol =

dehydration from alcohol puts more stress on a body fighting illness

Doxycycline mixed with alcohol

reduced effects of medication, nausea

Minocycline mixed with alcohol

liver disease, nausea, vomiting

Linezolid mixed with alcohol

unusual sweating, altered mental status, rapid heartbeat, abnormal heart rhythm, coma

Sulfamethoxazole, trimethoprim mixed with alcohol

folic acid deficiency, severe fatigue, nausea

Metronidazole mixed with alcohol

abdominal cramping, nausea, vomiting, headaches, facial flushing

Ciprofloxacin, levofloxacin, moxifloxacin mixed with alcohol

confusion, disorientation, memory loss

Antifungal drugs

treat systemic fungal infections, thrush, candidiasis - many metabolized by the cytochrome P-450 enzyme system - oral, topical, intravenous forms

Contraindications/cautions of antifungal drugs

liver disease, renal failure

Signs and symptoms of fungal infection

skin rash, skin lesions, nail bed infection, oral thrush

Amphotericin B (antifungal)

bind to sterols (ergosterol) in the cell membrane, causing the membranes to become leaky and die - given for severe, life-threatening fungal infections - oral or parenteral

Very severe SE/ADRs of amphotericin B

fever, chills, N/V, hypoxia, HTN/hypotension, arrhythmias, nephrotoxicity, neurotoxicity, visual disturbances, tinitis

Amphotericin B infusions

reduce the severity of infusion-related reactions with pretreatment of (antipyretic (acetaminophen), antihistamines (diphenhydramine), antiemetics, corticosteroids) - monitor serum BUN/creatinine, LFTs and electrolytes - may need electrolyte supplementation (K+, Mag++, Ca++, Po4-), force fluids - use IV infusion pumps and the most distal veins possible

Griseofulvin (antifungal)

older agent - oral preparation with long-term administration - binds to keratin, preventing fungal mitosis (cell division) by interfering with the mitotic spindle - for tinea corporis infections (ringworm), athlete’s foot, jock itch - monitor liver, kidney, bone marrow function for long-term prescription

Side effects of griseofulvin

HA, nausea, diarrhea, dizziness

Patient teaching for griseofulvin

take with a high-fat meal to increase absorption of med - no alcohol (causes disulfiram-like reaction - Antabuse) - photosensitivity (wear sunscreen, hats, long sleeves) - women use additional method if taking OCP (birth defects) - men use barrier method (affects sperm production)

Griseofulvin derived from…

penicillium molds, thus may see cross sensitivity with penicillin and griseofulvin

Nystatin (antifungal)

binds to sterols (ergosterol) in the cell membrane, causing the membranes to become leaky so the cells die - treats skin, mouth, GI tract infections

Side effects of nystatin

N/V/D, stomach pain

Nystatin oral lozenge or troche

slowly and completely dissolve in the mouth (don’t chew or swallow whole)

Nystatin suspension

swish and swallow, swish and spit

Fluconazole (diflucan) (antifungal)

targets lanosterol 14-alpha-demethylase, an enzyme needed to make ergosterol needed for fungal cell membrane production, cell membrane becomes leaky, cell dies - excellent DOC for vaginal candidiasis (yeast) infections - oral or by injection

Side effects of fluconazole

N/V/D, dizziness, rash, HA, elevated LFTs

Terbinafine (antifungal)

oral - blocks squalene epoxidase, an enzyme needed for ergosterol production, weakening fungal cell membrane - treats onychomycoses (fingernail/toe fungus)

Side effects of terbinafine

nausea, HA, dizziness, altered/metallic taste, muscle/joint aches

Nursing implications for antifungals

determine hypersensitivity, possible contraindications and conditions that require cautious use - obtain baseline VS, CBC, LFTs, renal function studies and EKG - assess for other meds to avoid drug interactions - for patient receiving IV infusions (monitor VS q 15-30 minutes, monitor I&O and daily weights)

Monitoring antifungal agents

monitor for therapeutic effects (easing of symptoms of infection, improved energy levels, normal VS including temp), monitor carefully for SE/ADRs, for potential hepatotoxicity (monitor LFTs, assess for jaundice), for potential nephrotoxicity (monitor BUN/creatinine, I&O daily weights, force fluids)

Patient teaching for antifungal agents

take full course of medications (don’t stop when you feel better, share meds, save meds and take evenly spaced doses), drug-drug and food-drug interactions, common SE for all (N/V/D), stay hydrated and avoid alcohol, stop and notify HCP (allergic reaction), stop and call 911 (anaphylaxis)

Antiviral drugs

used to treat infections caused by viruses other than HIV+ - inhibit viral replication (are not cures)

Herpes simplex antiviral drugs

acyclovir (Zovirax)

Shingles/severe varicella antiviral drugs

acyclovir (may be given IV)

Influenza antiviral drugs

amantadine (Symmetrel), rimantadine (Flumadine) approved for use with children

COVID-19 antiviral drugs

paxlovid - verify S&S began within the past 5 days

Common side effects of antiviral drugs

dizziness

Assessment for antiviral drugs

assess underlying disease and medical history including allergies, baseline VS and nutritional status, contraindications, cautious use (especially kidney and liver function) - verify S&S began within the past 24-72 hours - monitor LFTs, UO and daily weight, serum BUN and creatinine

Patient education for antiviral drugs

start therapy within 24-72 hours of S&S (paxlovid exception) - caution with activities requiring alertness - force fluids - tell patients to notify HCP if decreased UO, jaundice - consult primary HCP before taking any other medication (includes OTC) - take exactly as prescribed, for the full course of treatment - if topical ointments/solutions (hand hygiene, application)

Patient teaching for antiviral agents

take full course of medications (don’t stop when you feel better, share meds, save meds and take evenly spaced doses), drug-drug and food-drug interactions, common SE for all (N/V/D), no alcohol, stop and notify HCP (allergic reaction), stop and call 911 (anaphylaxis), for potential hepatotoxicity (monitor LFTs, assess for jaundice), for potential nephrotoxicity (monitor BUN/creatinine, I&O daily weights, force fluids)

Antiretroviral agents

treat HIV+ - goal is to find the regimen that will best control the infection with tolerable SE - not a cure but may decrease viral load to negligible and decrease S&S - drug therapy may need to be modified because of SEs - medication regimens often change throughout the illness

Monitoring antiretroviral agents for therapeutic effects

CD4 (helper T cell) increased, viral load decreased, delayed progression of AIDS, decrease in flu-like symptoms, decreased frequency of herpes flares

Side effects of antiretroviral drugs

anemia, neuropathy, hepatotoxicity, metabolic (lactic acidosis, lipodystrophy, diabetes, hyperlipidemia), GI (pancreatitis, N/V/D, anorexia), other (hypersensitivity reactions, sleep disturbances, malaise, fatigue, rash)

CCR5 antagonists and post-attachment inhibitors (HIV+ drug class)

block receptors on CD4 cells, interfere with HIV+ binding to host cell

Fusion inhibitors (HIV+ drug class)

binds to gp41 protein on HIV+ cell, prevents HIV+ from getting inside host cell

NRTIs (nucleoside reverse transcriptase inhibitors) and NNRTIs (non-nucleoside) (HIV+ drug class)

blocks DNA from forming and prevents it from entering host DNA for replication

Abacavir

an NRTI - mandatory screening for the HLA-B*5701 allele before starting - if positive, contraindicated due to Black Box warning for potential severe hypersensitivity reactions