Antibacterials

Narrow-spectrum antibiotics

works on FEW but SPECIFIC types of bacteria

Broad-spectrum antibiotics

works on VARIETY of bacteria

Bactericidal

Lethal to micro-organisms

(May be used more when patient is immunosuppressed)

Selecting an antibiotic

1.     Identify a CAUSATIVE AGENT

2.     SENSITIVITY of infecting organism to antimicrobial

3.     Other factors: location, age, prev. allergies, immune status

CSF infections

difficult for antibodies to reach due to BBB

Endocarditis

difficult for antibodies to reach thrombus can cover up infection

Purulent abscesses

difficult for antibodies to reach poor blood supple

Implanted objects

difficult for antibodies to reach due to weak immune response

SULFONAMIDE - pregnancy

can produce a severe neurologic disorder in newborns

GENTAMICIN - pregnancy

causes hearing loss in infants

TETRACYCLINES - pregnancy

cause discoloration of developing teeth. Toxicity more likely during pregnancy

Many antimicrobials are present in

… (Pregnancy)

Breastmilk

Combination Therapy – Additive or Potentiating

-help fight bacteria better (severe infections)

-treat infections of multiple microorganisms

-prevents bacterial resistance

-reduces toxicity risks (lower doses)

Combination Therapy – Adverse Events

-increase resistance to antibiotics

-increased cost

-increasing toxic reactions

-effects could fight each other

-interactions might decrease effectiveness

-increased risk for secondary infections

Prophylaxis: Prevention of infections for patients

-Abx may be given

-Pt. having GI, cardia, PV, orthopedic, or gynecologic surgery

-Sexual exposure to prevent STIs

-Before dental or other procedures in Pt. with prosthetic heart valves

Preventive Measures

i.     Hand hygiene—#1 measure to prevent INFECTION!!

 ii.     Invasive procedures (urinary catheter, IV catheter, etc.)

iii.     Immunizations up to date

iv.     Instruct patients to take FULL COURSE of antimicrobials to prevent resistance and recurrence

v.     Prevent transmission of resistant micro-organism by using PPE.

vi.     Evaluate effectiveness of treatment (post treatment cultures, monitor for clinical improvement)

Penicillin (Amoxicillin, Penicillin G, Ampicillin): MOA, C&C, A&T

1. Inhibits bacterial cell wall synthesis

2. Allergic reactions, cross-sensitivity with cephalosporins, GI upset

3. Take with food if GI upset, complete full course, report rash or difficulty breathing

Cephalosporins (Cephalexin, Ceftriaxone, Cefepime): MOA, C&C, A&T

1. Inhibits cell wall synthesis (bactericidal)

2. Allergy (especially with penicillin), superinfection, GI upset

3. Avoid alcohol, complete full course, watch for signs of allergic reaction

Carbapenems (Imipenem & Meropenem): MOA, C&C, A&T

1. Inhibits cell wall synthesis

2. Seizures (esp. in high doses), allergy to beta-lactams, GI discomfort

3. Monitor for CNS effects; use cautiously in renal impairment

Other inhibitors of cell wall synthesis (Vancomycin & Bacitracin): MOA, C&C, A&T

1. Inhibits cell wall synthesis

2. Nephrotoxicity, ototoxicity, "Red man syndrome" (with rapid infusion)

3. Administer IV slowly, monitor kidney function and trough levels

Tetracyclines (Doxycycline & Tetracycline): MOA, C&C, A&T

1. Inhibits cell wall synthesis

2. Photosensitivity, hepatotoxicity, tooth discoloration in kids/pregnancy, GI discomfort

3. Avoid dairy, antacids, and iron; take on empty stomach; use sun protection

Macroslides (Azithromycin & Erythromycin): MOA, C&C, A&T

1. Inhibit protein synthesis (50S ribosome)

2. QT prolongation, hepatotoxicity, GI discomfort

3. Take with food if GI upset; report palpitations or jaundice

Amino-glycosides (Gentamicin & Tobramycin): MOA, C&C, A&T

1. Inhibit protein synthesis (30S ribosome, bactericidal)

2. Nephrotoxicity, ototoxicity, neuromuscular blockade

3. Monitor drug levels, kidney function, and hearing

Sulfonamides & Trimethoprim (Folate Antagonist), Sulfamethoxazole + Trimethoprim (SMX-TMP): MOA, C&C, A&T

1. Inhibit folic acid synthesis

2. Stevens-Johnson syndrome, crystalluria, blood dyscrasias

3. Drink plenty of water, use sun

   protection, monitor for rash

Urinary Tract Antiseptics (Nitrofurantoin): MOA, C&C, A&T

1. Damages bacterial DNA

2. Pulmonary reactions, hepatotoxicity, GI upset

3. Take with food, avoid in renal impairment, may discolor urine (brown)

Fluoroquinolones (Ciprofloxacin & Levofloxacin): MOA, C&C, A&T

1. Inhibit DNA gyrase/topoisomerase

2. Tendon rupture, QT prolongation, photosensitivity, GI discomfort

3. Avoid antacids/dairy, use sun protection, report joint pain

Nitroimidazoles (Metronidazole): MOA, C&C, A&T

1. Disrupt DNA synthesis

2. Metallic taste, neurotoxicity, disulfiram-like reaction with alcohol, GI discomfort

3. Avoid alcohol, take with food, may darken urine

Disulfiram Reaction:

headache, hypotension, flushing, palpitations, nausea, thirst, chest pain

Blood Dyscrasias:

hemolytic anemia, agranulocytosis, leukopenia, thrombocytopenia, aplastic anemia, megaloblastic anemia, hepatotoxicity

Kernicterus:

jaundice, increased bilirubin levels (neurotoxic for newborns)

Stevens-Johnson Syndrome:

flu-like symptoms, painful rash that spreads and blisters

Suprainfection:

colitis (diarrhea), yeast infections (mouth, pharynx, vagina, bowels)

Ototoxicity:

acute hearing loss, vertigo, tinnitus

Nephrotoxicity:

decreased urine output, altered labs (BUN, Creatinine), hematuria, cloudy urine

Photosensitivity & Toxicity:

severe sunburn from direct or indirect sunlight (even with sunscreen)

Vancomycin Flushing Syndrome:

Flushing of face, neck, pruritic, hypotension, dizziness

Hormonal Contraceptive Interference

use additional forms of contraception

Spontaneous Tendon Rupture:

pain, swelling, redness at the tendon sites (Achilles site common)