Functional class
Func. class.: Broad-spectrum antiinfective
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Drug reference
Func. class.: Broad-spectrum antiinfective
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Chem. class.: Natural penicillin
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ACTION: Interferes with cell-wall replication of susceptible organisms; lysis is mediated by cell-wall autolytic enzymes, results in cell death
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USES: Respiratory infections, scarlet fever, erysipelas, otitis media, pneumonia, skin and soft-tissue infections, gonorrhea; effective for gram-positive cocci (Staphylococcus, Streptococcus pyo genes, S. viridans, S. faecalis, S. bovis, S. pneumoniae), gram-negative cocci (Neis seria gonorrhoeae), gram-positive bacilli (Actinomyces, Bacillus anthracis, Clos tridium perfringens, C. tetani, Corynebacterium diphtheriae, Listeria monocytogenes), gram-negative bacilli (Escherichia coli, Proteus mirabilis, Salmonella, Shigella, Enterobacter, Strep tobacillus moniliformis), spirochetes (Treponema pallidum)
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CONTRAINDICATIONS: Hyper sensitivity to penicillins Precautions: Pregnancy, breastfeeding; hypersensitivity to cephalosporins, car- bapenem, sulfites; severe renal disease, GI disease, asthma, CDAD, electrolyte imbalance, geriatrics, infants, neonates
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Black Box Warning: Penicillin G benza- thine: IV use, may be fatal
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SIDE EFFECTS CNS: Lethargy, hallucinations, anxiety, depression, twitching, coma, seizures, hyperreflexia GI: Nausea, vomiting, diarrhea, increased AST, ALT, abdominal pain, glos- sitis, colitis, CDAD GU: Oliguria, proteinuria, hematuria, vag initis, moniliasis, glomerulonephritis, renal tubular damage HEMA: Anemia, increased bleeding time, bone marrow depression, granulocytope- nia, hemolytic anemia META: Hypo/hyperkalemia, alkalosis, hypernatremia MISC: Anaphylaxis, serum sickness, Stevens-Johnson syndrome, local pain, tenderness and fever with IM inj
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INTERACTIONS Increase: penicillin effect—aspirin, probenecid Increase: effect of heparin, methotrexate Decrease: effect of oral contraceptives, typhoid vaccine Decrease: antimicrobial effect of penicillin—tetracyclines Drug/Lab Test False positive: urine glucose, urine protein
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DOSAGE AND ROUTES Penicillin G benzathine Early syphilis • Adult: IM 2.4 million units in single dose Congenital syphilis • Child <2 yr: IM 50,000 units/kg in single dose, max 2.4 million units as single inj Prophylaxis of rheumatic fever, glomerulonephritis • Adult/child >27 kg: IM 1.2 million units as single dose • Child ≤27 kg: IM 600,000 units as single dose Most infections • Adult/child >27 kg: IM 1.2 million units as single dose • Child ≤27 kg: IM 600,000 units as P single dose
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Available forms: Inj 600,000 units/mL Penicillin G Potassium Pneumococcal/streptococcal infec- tions (serious) • Adult: IM/IV 5-24 million units in di- vided doses q4-6hr • Child <12 yr: IV 150,000-300,000 units/kg/day in 4-6 divided doses; max 24 million units/day Most infections • Adult: IM/IV 1-5 million units q4-6hr • Child: IM/IV 8333-16,667 units/kg q4hr; 12,550-25,000 units/kg q6hr; up to 250,000 units/kg daily in divided doses, if more serious 300,000 units/kg daily • Infant >7 days: IV 25,000 units/kg q8hr; meningitis up to 75,000 units/kg q6hr • Infant <7 days: IV 25,000 units/kg q12hr, meningitis 100,000-150,000 units/kg daily in divided doses Renal dose • CCr <10 mL/min, give full loading dose then 1/2 of loading dose q8-10hr Available forms: Powder for inj 1, 5, 20 million units/vial; inj 1, 2, 3 million units/50 mL Penicillin G procaine Moderate to severe pneumococcal infections • Adult: IM 600,000-1 million units as single dose or divided bid doses/day for 10 days to 2 wk • Child: IM 50,000 units/kg daily × 10- 14 days (congenital syphilis) Available forms: Inj 600,000, units/mL Penicillin V Most infections • Adult/adolescent/child >12 yr: PO 1-4 g in 3-4 divided doses • Child <12 yr: PO 25-100 mg/kg/day in 3-4 divided doses, max 3 g/day Group A beta-hemolytic streptococcal infections • Adult/child >12 yr: PO 1-4 g/day in divided doses Available forms: Tabs 250, 500 mg; powder for oral sol 125, 250 mg/5 mL
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Administer: • Store in dry, tight container; oral susp refrigerated 2 wk Penicillin G benzathine • No dilution needed, shake well, give slowly deep IM inj in large muscle mass; avoid intravascular inj; aspirate; do not give IV Penicillin G • Aspirate before use • Penicillin G sodium or potassium can be given IM or IV, vials containing 10 or 20 million units not for IM use Intermittent IV INFUSION route • Vials/bulk packages: dilute according to manufacturer’s directions • Frozen bags: thaw at room temperature, do not force thaw, no reconstitution needed • Final concentration (100,000-500,000 units/mL—adults; 50,000 units/mL— neonate/infant) • Total daily dose divided q4-6hr and given over 1-2 hr (adult), 15 min (infant/neonate) Penicillin G procaine • No dilution needed; give deep IM inj; avoid intravascular inj; aspirate; do not give IV Penicillin V • Orally on empty stomach for best ab- sorption • Oral susp: tap bottle to loosen, add 1/2 total amount of water, shake, add remaining water, shake; final concen- tration 125 or 250 mg/mL, store in refrigerator after reconstitution, dis- card after 14 days
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Assess: • Infection: temperature; characteristics of sputum, wounds, urine, stools before, during, after treatment; C&S before ther- apy; product may be given as soon as culture is taken • GU status: I&O ratio; report hematuria, oliguria because penicillin in high doses is nephrotoxic; renal tests: urinalysis, protein, blood • Renal disease: any patient with com- promised renal system because product is excreted slowly with poor renal system function; toxicity may occur rapidly • Hepatic studies: AST, ALT • Blood studies: WBC, RBC, Hct, HB, bleeding time • CDAD: diarrhea, mucus, pus; bowel pattern before, during treatment • Respiratory status: rate, character, wheezing, tightness in chest • Allergies before initiation of treatment, reaction to each medication; because of prolonged action, allergic reaction may be prolonged and severe; watch for anaphylaxis: rash, dyspnea, pruritus, laryngeal edema; skin eruptions after administration of penicillin to 1 wk after discontinuing product • EPINEPHrine, suction, tracheostomy set, endotracheal intubation equipment • Scratch test to assess allergy after secur- ing order from prescriber; usually done when penicillin is only product of choice
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Evaluate: • Therapeutic response: resolution of infection
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CLINICAL CONSIDERATIONS
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Patient and caregiver information: • To report sore throat, fever, fatigue; may indicate superinfection; CNS effects: depression, hallucinations, seizures • To wear or carry emergency ID if al- lergic to penicillins • CDAD: To report diarrhea with blood, pus, mucus to prevent dehydration • To shake susp well before each dose; to store in refrigerator for up to 2 wk • To use all medication prescribed TREATMENT OF ANAPHY LAXIS: Withdraw product; maintain airway; administer EPINEPHrine, aminophylline, O2, IV corticosteroids
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PHARMACOKINETICS Penicillin G benzathine: IM: Very slow absorption; time to peak 12-24 hr; duration 21-28 days; excreted in urine, feces, breast milk; crosses placenta Penicillin G: IV: Peak immediate IM: Peak 1/4-1/2 hr PO: Peak 1 hr, duration 6 hr Excreted in urine unchanged, excreted in breast milk, crosses placenta, half-life 30-60 min Penicillin G procaine: IM: Peak 1-4 hr, duration 15 hr, excreted in urine Penicillin V: PO: Peak 30-60 min, half- life 30 min, excreted in urine, breast milk
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• Adult: IM 2.4 million units in single dose Congenital syphilis
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• Child <2 yr: IM 50,000 units/kg in single dose, max 2.4 million units as single inj Prophylaxis of rheumatic fever, glomerulonephritis
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• Adult/child >27 kg: IM 1.2 million units as single dose
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• Child ≤27 kg: IM 600,000 units as single dose Most infections
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• Adult/child >27 kg: IM 1.2 million units as single dose
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• Child ≤27 kg: IM 600,000 units as P single dose
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