Pharm study guide questions

General Principles

What microorganisms do antibacterials, antivirals, and antifungals treat?

  • Antibacterials (antibiotics) → bacteria

  • Antivirals → viruses

  • Antifungals → fungi

Signs of hypersensitivity and anaphylactic reactions:

  • Hypersensitivity (skin): rash, urticaria, pruritus, swelling

  • Anaphylactic: tightness in throat, chest tightness, wheezing, dyspnea

Superinfections — definition and examples: A new infection that occurs because of antibiotic use (destruction of normal flora). Examples:

  • Thrush: creamy white lesions and sore mouth

  • Vaginal yeast infection: perineal itching, thick white vaginal discharge

  • Pseudomembranous colitis (C. diff): persistent or bloody diarrhea, fever, abdominal pain — may be fatal; stop med, collect stool specimen

Why obtain a culture BEFORE the first dose? To identify the causative organism so that definitive therapy (based on known culture/sensitivity results) can guide treatment.

Empiric vs. Definitive vs. Prophylactic therapy:

  1. Empiric: Treat a likely cause of infection before the specific bacteria is known

  2. Definitive: Administer antibiotics based on known culture and sensitivity results

  3. Prophylactic: Antibiotics taken before anticipated exposure to an infectious organism to prevent infection

Narrow therapeutic index: A narrow margin of safety — small difference between the effective dose and the toxic dose. Small increases in drug levels can cause toxicity; small decreases can cause therapeutic failure. Blood levels must be monitored closely.

General nursing assessment, monitoring, and teaching for anti-infectives:

  • Monitor for hypersensitivity/anaphylaxis

  • Assess for superinfection signs

  • Ensure culture obtained before first dose

  • Teach patients to complete the full antibiotic course even if feeling better

  • Never save antibiotics for later

  • Antibiotics treat bacterial infections only — not viral or fungal

Vancomycin

Uses: Serious gram-positive infections; PO for severe C. diff; IV for MRSA

Peak and trough timing:

  • Peak: measured after completion of infusion (highest drug level)

  • Trough: measured within 30 min before the next dose (lowest drug level); therapeutic trough is 10–20 mcg/mL

Adverse effects/toxicities:

  • Ototoxicity (irreversible): tinnitus, hearing loss, dizziness — perform whisper test

  • Nephrotoxicity: ↑BUN & creatinine, ↓urine output, hematuria, edema. If creatinine >1.2 or BUN >20, withhold and contact provider. Ensure ≥2 L fluid/day.

Before infusing Vancomycin / drugs to avoid:

  • Check trough level, assess hearing, assess renal function (creatinine & BUN), check IV site

  • Avoid ototoxic meds: aminoglycosides, furosemide

  • Avoid nephrotoxic meds: aminoglycosides, NSAIDs, cyclosporine

IV infusion:

  • Infuse over at least 1 hour; peripheral IV in a large vein; watch for thrombophlebitis/extravasation

Red Man Syndrome:

  • Caused by infusing too fast (histamine release) — NOT a true allergic reaction

  • Symptoms: flushing (face, neck, chest), erythema, pruritus, hypotension, dyspnea, tachycardia, chest pain, myalgia

  • Management: hold infusion, restart at slower rate once symptoms resolve; monitor VS/lung sounds; may give diphenhydramine and/or steroids

Metronidazole (Flagyl)

  • No alcohol 24 hours before or 36 hours after last dose (causes disulfiram-like reaction: tachycardia, hypotension)

  • Avoid OTC antitussives (may contain alcohol)

  • For trichomoniasis: all sexual partners must be treated simultaneously; avoid sexual intercourse until treatment is completed

  • Harmless darkening of urine may occur; can take with food to reduce GI distress

Macrolides

Names: Erythromycin, Azithromycin (Zithromax), Clarithromycin (Biaxin) — end in "-thromycin" (mnemonic: ACE)

Uses: Respiratory tract infections, gonorrhea, Chlamydia; alternative for penicillin-allergic patients

Common side effects: Nausea, anorexia, GI distress, mild diarrhea; may reduce efficacy of oral contraceptives

Adverse effects to report:

  • Hepatotoxicity: fatigue, elevated LFTs, abdominal pain, dark urine, pale stools, jaundice

  • QT prolongation: cardiac arrhythmias

Tetracyclines

Names: Tetracycline (Sumycin), Doxycycline (Vibramycin), Minocycline (Minocin), Demeclocycline, Tigecycline — end in "-cycline"

Uses: Rocky Mountain spotted fever, Lyme disease, acne, Chlamydia, H. pylori, skin infections

Warnings: Bind to Ca²⁺, Mg²⁺, Al³⁺ ions forming insoluble complexes; strong affinity for calcium

Foods/products to avoid: Dairy products (milk, cheese, yogurt), antacids, iron preparations, sucralfate — all reduce oral absorption. Take with 6–8 oz of water.

Contraindications: Pregnancy, lactation, children under 8 years old

Side effects: Photosensitivity (wear sunscreen 30 min before sun exposure), superinfections (C. diff, yeast infection), may suppress bone growth, may reduce efficacy of oral contraceptives

Why not for children <8 or pregnant/nursing women? Tetracyclines bind to calcium in developing teeth and bones → permanent tooth discoloration and possible suppressed bone growth in fetuses, infants, and young children.

Aminoglycosides

Names (mnemonic GNATS): Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin — end in "-micin"/"-mycin"

Why monitor drug blood levels / when to check trough: To prevent toxicity; trough checked within 30 minutes before the next dose. High trough levels increase risk of toxicity.

Toxicities:

  • Ototoxicity: dizziness, balance issues, tinnitus, hearing loss — assess with baseline hearing/vestibular tests

  • Nephrotoxicity: proteinuria, ↑BUN & creatinine — monitor renal function, urine output, encourage fluids; do NOT give if creatinine >1.2

Assessing for nephrotoxicity/ototoxicity:

  • Nephrotoxicity: monitor BUN & creatinine, urine output

  • Ototoxicity: perform hearing tests, ask about ringing in ears (tinnitus), dizziness/balance issues

Fluoroquinolones

Names (end in "-floxacin"): Ciprofloxacin (Cipro), Levofloxacin (Levaquin), Moxifloxacin (Avelox), Gemifloxacin, Delafloxacin

FDA Black Box Warning: Tendinitis and tendon rupture

Adverse effects: CNS (confusion, neuropathy, depression), GI (pseudomembranous colitis, C. diff, hepatotoxicity), CV (prolonged QT interval), Skin (rash, pruritus, photosensitivity)

Interactions to avoid:

  • Antacids, dairy, calcium, magnesium, aluminum, iron, zinc, sucralfate — reduce absorption

  • Macrolides, beta blockers — prolong QT interval

Timing of interacting medications: Take interacting drugs at least 2 hours before OR 2 hours after fluoroquinolones. Take with at least 2,000 mL of fluid/day to prevent crystalluria.

Sulfonamides

Names: Sulfisoxazole; Sulfamethoxazole-trimethoprim (SMX-TMP/Bactrim)

Uses: UTIs, Staphylococcus infections; SMX-TMP acts synergistically

Adverse effects / monitoring:

  • Stevens-Johnson Syndrome (rare, life-threatening): flu-like symptoms, fever, rash, blisters, widespread peeling skin/mucous membranes

  • Agranulocytosis, hemolytic anemia, thrombocytopenia → monitor CBC; report sore throat, fever

  • Photosensitivity; "sulfa allergy" — delayed rash reaction

Cross-sensitivity drug: Celecoxib (Celebrex) — contains sulfonamide; avoid with sulfa allergy

Drug interactions:

  • May increase hypoglycemia risk with sulfonylureas

  • May increase bleeding risk with warfarin

  • May potentiate toxicity of phenytoin (antiseizure)

  • May reduce efficacy of oral contraceptives

  • Drink ≥2,000 mL fluid/day

Penicillin

Names:

  • Natural: Penicillin G, Penicillin V

  • Penicillinase-resistant: Nafcillin, Cloxacillin, Oxacillin, Dicloxacillin

  • Aminopenicillins: Amoxicillin, Ampicillin

  • Extended-spectrum: Carbenicillin, Piperacillin, Ticarcillin

  • Beta-lactamase inhibitor combos: Ampicillin/sulbactam (Unasyn), Amoxicillin/clavulanate (Augmentin), Ticarcillin/clavulanate (Timentin), Piperacillin/tazobactam (Zosyn)

Why combine with clavulanate/sulbactam/tazobactam? Some bacteria produce beta-lactamases that destroy penicillin. These inhibitors block beta-lactamase, protecting penicillin from destruction.

Major adverse effect / allergic reaction signs:

  • Allergic: urticaria, rash/hives, pruritus, fever — stop medication

  • Anaphylaxis: tightness in throat, wheezing, dyspnea — medical emergency

Treating anaphylaxis: Administer epinephrine into the outer thigh (can be through clothing), hold for 3 seconds. Have a second epi-pen ready. Seek immediate medical care.

Cross-sensitivity: Patients allergic to penicillin may also react to cephalosporins (avoid if severe penicillin allergy)

Foods to avoid: Water only (not juices); avoid caffeine, citrus fruits, fruit juices, tomato juice

Nursing implications: Assess allergy history; rash = most common adverse effect (can progress to anaphylaxis); report itching, rash, hives, difficulty swallowing, swollen throat; monitor I&O and renal function if impaired; may reduce oral contraceptive efficacy

Cephalosporins

Names (start with Cef-/Ceph-):

  • 1st gen: Cephalexin (Keflex), Cefazolin (Ancef)

  • 2nd gen: Cefaclor, Cefprozil, Cefoxitin (Mefoxin — a 2nd gen cephalosporin), Cefuroxime, Cefotetan

  • 3rd gen: Ceftriaxone (Rocephin), Cefotaxime, Cefdinir, Cefixime, Ceftazidime

  • 4th gen: Cefepime (Maxipime)

  • 5th gen: Ceftaroline (Teflaro) — only cephalosporin effective against MRSA

Cross-sensitivity with penicillin: Patients with severe penicillin allergy should NOT receive cephalosporins due to shared beta-lactam structure.

How some treat meningitis: 3rd gen (e.g., ceftriaxone) can reach cerebrospinal fluid (CSF) to treat meningitis.

Nursing implications: Monitor for allergic reactions; avoid alcohol (cefazolin/cefotetan → disulfiram-like reaction); antacids and iron decrease effectiveness; may reduce oral contraceptive efficacy

Miscellaneous

Clindamycin: Serious risk = pseudomembranous colitis (C. diff). Report persistent diarrhea; discontinue medication; collect stool specimens.

Nitrofurantoin (Macrobid): Used for UTIs. Side/adverse effects: GI distress (take with food), harmless dark yellow/brown urine, pulmonary toxicity (cough, chest pain, dyspnea), liver toxicity (↑ALT/AST, jaundice). Increase fluid intake; contraindicated in significant renal impairment.

Phenazopyridine (Pyridium): Urinary tract analgesic (not an antibiotic) — relieves pain from cystitis. Turns urine red or orange. Take after meals to reduce GI upset.

Linezolid (Zyvox): Used for multidrug-resistant gram-positive bacteria (VRE, MRSA). Avoid tyramine-containing foods (cheese, wine, soy sauce, smoked/cured meats/fish) → can cause hypertensive reaction. Avoid SSRIs → serotonin syndrome. (If they eat pepperoni and cheese: hypertensive crisis risk.)

Antiviral Drugs

Influenza medications: Oseltamivir (Tamiflu), Zanamivir, Peramivir. Start within 2 days of symptom onset. Maintain hydration (drugs excreted in urine).

Vitamin C: Enhances absorption of iron (ferrous sulfate). Excessive doses → nausea, vomiting, diarrhea, renal stones.

Echinacea: Topical use for wounds/canker sores; oral use may stimulate the immune system for common colds.

Herpes treatment: Acyclovir — drug of choice for HSV-1, HSV-2, and herpes-zoster (VZV/shingles). Increase daily fluid intake.

Hepatitis C:

  • Monitor interferons for: depression/suicidal ideation, hepatotoxicity, myelosuppression (CBC + LFTs)

  • Interferons adverse effects: depression, suicidal ideation, hepatotoxicity, myelosuppression

  • Combination therapy (interferon + ribavirin): associated with decreased hemoglobin/anemia (fatigue); monitor CBC; reduces drug resistance

HIV:

  • Goal: reduce viral load to undetectable (<50 copies/mL) in blood

  • Does NOT cure HIV or completely prevent transmission

  • Combination therapy (HAART — at least 3 medications) is used to decrease drug resistance; medications work in different ways to reduce viral load

Antifungal Drugs

Uses: Treat infections caused by fungi (yeasts, molds)

Onychomycosis: Nail fungal infection causing nails to turn yellow

Candidiasis:

  • Can occur after antibiotic therapy or immunosuppressants

  • Thrush (oral candidiasis): white lesions in mouth

  • Vaginal candidiasis: yeast infection

Azole adverse effects (e.g., fluconazole): Hepatotoxicity — monitor ↑LFTs (ALT/AST); report dark urine, clay-colored stools, jaundice. Hypokalemia (dysrhythmias). Do NOT give with hepatic impairment/alcoholism.

Drugs/food to avoid with azoles: Antacids, grapefruit juice (increases azole toxicity). Also: warfarin (↑bleeding), statins (↑rhabdomyolysis risk), phenytoin (↑CNS toxicity).

How azoles affect other drugs: Inhibit cytochrome P-450 enzymes → increases levels of many other drugs.

Vaginal cream teaching: Abstain from sexual intercourse until treatment is completed and infection resolved; take medication even if menstruating; notify provider if symptoms persist.

Terbinafine (Lamisil):

  • Uses: Oral → onychomycosis (nail fungus); Topical → tinea pedis (athlete's foot), tinea cruris (jock itch), tinea corporis (ringworm)

  • Adverse effects to report: fatigue, stomach pain, loss of appetite, dark urine, clay-colored stools, jaundice, ↑ALT/AST

  • Monitor: liver function tests

  • Contraindications: hepatic impairment, hepatitis, alcoholism

Nystatin:

  • Oral lozenge: slowly and completely dissolve in mouth (do NOT chew or swallow whole)

  • Suspension: swish thoroughly in mouth before swallowing

Amphotericin B:

  • Adverse effects: infusion reactions (fever, chills, nausea, hypotension, headache, anemia), nephrotoxicity, hypokalemia

  • Monitor: I&O, BUN, creatinine (>1.2 = concern), weight, potassium (<3.5 mEq/L = hypokalemia)

  • Reduce infusion reactions: infuse over 2–6 hours; pretreat with acetaminophen, antihistamines, corticosteroids; avoid other nephrotoxic drugs (aminoglycosides, NSAIDs, cyclosporine)

Cyclosporine (Immunosuppressant)

  1. MOA & Indications: Inhibits immune responses by suppressing T cell activity. Used to prevent organ transplant rejection and treat autoimmune conditions.

  2. Adverse effects: Nephrotoxicity, increased risk of infections, risk of malignancies, tremors (12–55%)

  3. St. John's Wort effect: Lowers (↓) cyclosporine levels — reduces drug effectiveness, risk of transplant rejection

  4. Nephrotoxic drugs to avoid: Aminoglycosides, amphotericin B, NSAIDs (cyclosporine itself is also nephrotoxic — avoid combining)