PENICILLIN G BENZATHINE

PENICILLIN G BENZATHINE (pen-i-sill'in) Bicillin, Bicillin L-A, Permapen Classifications: beta-lactam antibiotic; natural penicillin; Therapeutic: antibiotic; beta-lactam Prototype: Penicillin G potassium Pregnancy Category: B

Availability

300,000 units/mL, 600,000 units/mL, 1,200,000 units/2 mL, 2,400,000 units/4 mL injection

Action

Acid-stable, penicillinase-sensitive, long-acting form of penicillin G. Absorbed slowly in body because of extremely low water solubility. Produces lower blood concentrations than other penicillin G compounds but has the longest duration of antimicrobial activity of all other available parenteral or repository penicillins.

Therapeutic Effect

Effective against many strains of Staphylococcus aureus, gram-positive cocci, gram-negative cocci. Also effective against gram-positive bacilli and gram-negative bacilli.

Uses

Infections highly susceptible to penicillin G, such as streptococcal, pneumococcal, and staphylococcal infections, venereal disease such as syphilis (including early, late, and congenital forms), and nonvenereal diseases (e.g., yaws, bejel, and pinta). Also used in prophylaxis of rheumatic fever.

Contraindications

Hypersensitivity to penicillins or cephalosporins; lactation.

Cautious Use

History of or suspected allergy (eczema, hives, hay fever, asthma); renal disease, renal impairment; GI disease; pregnancy (category B); infants, neonates.

Route & Dosage

Mild to Moderate Infections Adult: IM 1,200,000 U once/d Child: IM >27 kg, 900,000 U once/d; <27 kg, 300,000–600,000 U once/d Syphilis Adult: IM <1 y duration: 2,400,000 U as single dose; >1 y duration: 2,400,000 U/wk for 3 wk Child: IM Congenital: 50,000 U/kg as single dose Prophylaxis for Rheumatic Fever Adult: IM 1,200,000 U q4wk Child: IM 1,200,000 U q3–4wk

Administration

Intramuscular

• Do not confuse penicillin G benzathine with preparations containing procaine penicillin G (e.g., Bicillin C-R).
• Make IM injection deep into upper outer quadrant of buttock. In infants and small children, the preferred site is the midlateral aspect of the thigh.
• Shake multiple-dose vial vigorously before withdrawing desired IM dose. Shake prepared cartridge unit vigorously before injecting drug.
• Select IM site with care. Injection into or near a major peripheral nerve can result in nerve damage.
• Inadvertent IV administration has resulted in arterial occlusion and cardiac arrest.
• Make injections at a slow steady rate to prevent needle blockage.
• Store at 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

Body as a Whole: Local pain, tenderness, and fever associated with IM injection, chills, fever, wheezing, anaphylaxis, neuropathy, nephrotoxicity; superinfections, Jarisch-Herxheimer reaction in patients with syphilis. Skin: Pruritus, urticaria, and other skin eruptions. Hematologic: Eosinophilia, hemolytic anemia, and other blood abnormalities. Also see PENICILLIN G POTASSIUM.

Interactions

Drug: Probenecid decreases renal elimination; may decrease efficacy of oral contraceptives.

Pharmacokinetics

Absorption: Slowly absorbed from IM site. Peak: 12–24 h. Duration: 26 d. Distribution: Crosses placenta; distributed into breast milk. Metabolism: Hydrolyzed to penicillin in body. Elimination: Excreted slowly by kidneys.

Nursing Implications

Note: See penicillin G potassium for numerous additional clinical implications.

Assessment & Drug Effects

• Determine history of hypersensitivity reactions to penicillins, cephalosporins, or other allergens prior to initiation of drug therapy.
• Lab tests: Perform C&S tests prior to initiation of therapy and periodically thereafter. Perform periodic renal function tests.

Patient & Family Education

• Report immediately to physician the onset of an allergic reaction. There is great risk of severe and prolonged reactions because drug is absorbed so slowly.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug