Antibiotics Quang Truong Jennafer McCoy

Categories of IV antibiotic medications  Sulfonamides - Treatment: UTIs and GI Infections  Penicillins - Bactericidal agents, many therapeutic uses; prevents bacteria from forming rigid walls  Cephalosporins - Same mechanism as penicillin, cover a broader spectrum of organisms  Tetracyclines - Bacteriostatic  Quinolones- Penetrate bone and joints  Aminoglycosides - Commonly used against serious life-threatening (septic) infections; Bactericidal

Uses for the drugs  1)Inhibit cell wall formation  2)Block protein formation  3)Disrupt cell membrane  4)Interfere with DNA formation  5)Prevent folic acid synthesis

Dosages & How they are calculated  Sulfonamide-Bactrim IV dose: 8-10mg/kg/day divided q6-12h Calculated: By appropriate culture/susceptibility studies  Penicillin-Penicillin G IV dose: 2-24 million units/day in divided doses q4h Calculated: Depending on organism sensitivity and severity of infection  Cephalosporin-Cefoxitin IV dose: 1g- 2g q6-8h Calculated: By causative organism susceptibility, severity of infection, and patient’s condition  Tetracyclines-Minocycline IV dose: 100mg q12h not to exceed 400mg/24hs Calculated: With culture and susceptibility information  Quinolones-Ciprofloxacin IV dose: 500mg q12h for 4 to 6 wks. Calculated: By severity/nature of the infection, integrity of patient’s host-defense mechanisms, and status of renal/hepatic function  Aminoglycosides-Amikacin IV dose: 5 to 7.5 mg/kg/dose q8h Calculated: Based on IBW or adjusted body weight if current weight is > than 25-30% over IBW

Action  Bactericidal Vs. Bacteriostatic  Bacteriostatic is capable of inhibiting the growth or reproduction of bacteria  Bactericidal is capable of killing bacteria outright

Onset and duration of action  Onset-immediately since the medications are given intravenously  Duration- Varies according to duration of treatment; the effects of continue to work after treatment is completed

Contraindications  Patients should avoid sun, dairy, antacids, anticoagulants, anti-seizures, consuming alcohol or medications containing alcohol, pregnancy, and breastfeeding, etc. (varies depending specific type of antibiotic)

Possible drug interactions  Ruins the effects of the antibiotic or could cause a severe reaction.  Anti-seizure  Anticoagulants  Bethkis (tobramycin) Bethkis (tobramycin)  Cisatracurium Cisatracurium  Doxacurium Doxacurium

Potential dangers associated with use  Sulfonamides – rash, N/V, HA  Penicillins – diarrhea, N/V  Cephalosporins – similar to penicillin  Tetracyclines - GI discomfort, N/V; Can cause fatal renal syndrome  Quinolones - GI discomfort, N/V, dizziness  Aminoglycosides - mild hearing loss, mild dizziness, clumsiness, N/V, etc.

Length of time on market  Sulfonamides – Discovered in 1932, marketed in 1935  Penicillins – Discovered in 1928, marketed on March 15, 1945  Cephalosporins – Discovered in 1950, marketed in 1964  Tetracyclines – Discovered in 1948, marketed in 1955  Quinolones – Discovered in 1962, marketed for clinical use in 1967  Aminoglycosides – Discovered in 1943, marketed in 1963

Cost  IV medications are more costly  Switching from (IV) to oral (PO) therapy as soon as patients are clinically stable can reduce the length of hospitalization and lower associated costs  While intravenous medications may be more bioavailable and have greater effects, some oral drugs produce serum levels that are the same or comparable to those of the IV form

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