penicillin G benzathine

penicillin G benzathine,

a long-acting depot form of penicillin.

indications It is used primarily for the treatment of syphilitic infection outside the central nervous system. It is given by deep intramuscular injection to achieve steady concentrations in the plasma and to slow systemic absorption from the repository in the muscle. Absorption occurs in a period that ranges from 12 hours to several days. It may be administered as prophylaxis against susceptible strains of bacteria, primarily gram-positive bacteria.

contraindications Hypersensitivity to this drug or to other penicillins prohibits its use.

adverse effects The most serious adverse effect is anaphylaxis. The most common side effects are diarrhea, maculopapular rash, urticarial rash, fever, bronchospasm, vasculitis, serum sickness, and exfoliative dermatitis.

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penicillin (pen´isil´in),

n an antibiotic secured from cultures of
P. notatum, being bactericidal for gram-positive cocci, some gram-negative cocci (gonococcus and meningococcus), and clostridial and spirochetal organisms. Its topical application to the oral mucusa membranes is discouraged because of the high risk of sensitization from local application of antibiotic substances.

penicillin G,

n an acid-sensitive form of penicillin prepared as penicillin G benzathine and penicillin G procaine used for deep intramuscular administration. It is slowly released, resulting in prolonged effective blood levels. In past dentistry, it was used prophylactically for patients predisposed to bacterial endocarditis prior to any invasive dental procedure. Now it has been replaced by amoxicillin. It has a high allergy potential. See also penicillin G benzathine.

penicillin G benzathine,

n brand names: Bicillin L-A, Permapen;
drug class: benzathine salt of natural penicillin;
action: interferes with cell wall replication of susceptible organisms; osmotically unstable cell wall swells and bursts from osmotic pressure;
uses: respiratory infections, scarlet fever, erysipelas, otitis media, pneumonia, skin and soft tissue infections, and yaws.

penicillin V potassium/penicillin V,

n brand names: Beepen-VK, Betapen-VK, V-Cillin K, Veetids, others;
drug class: semisynthetic penicillin;
action: interferes with cell wall replication of susceptible organisms; the cell wall, rendered osmotically unstable, swells and bursts from osmotic pressure;
uses: effective for both gram-positive cocci and gram-negative bacilli.

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penicillin G benzathine

Bicillin L-A, Megacillin (CA), Permapen

Pharmacologic class: Penicillin

Therapeutic class: Anti-infective

Pregnancy risk category B

Action

Inhibits biosynthesis of cell-wall mucopeptide; kills penicillin-susceptible bacteria during active multiplication stage

Availability

Suspension for I.M. injection: 600,000 units/ml in 1-, 2-, and 4-ml prefilled syringes

⊘Indications and dosages

➣ Upper respiratory infections

Adults: 1.2 million units I.M. as a single dose

Children weighing 27 kg (60) or more: 900,000 units I.M. as a single dose

Infants and children weighing less than 27 kg (60 lb): 300,000 to 600,000 units I.M. as a single dose

➣ Early syphilis (primary, secondary, or latent)

Adults: 2.4 million units I.M. as a single dose

Children: 50,000 units/kg I.M. as a single dose, increased as needed up to adult dosage

➣ Congenital syphilis

Children younger than age 2: 50,000 units/kg I.M. as a single dose

➣ Late (tertiary) syphilis and neurosyphilis

Adults: 2.4 million units I.M. q week for up to 3 weeks, after aqueous penicillin G or procaine penicillin therapy

➣ Gummas and cardiovascular syphilis

Adults: 2.4 million units I.M. q week for 3 weeks

➣ Yaws, bejel, and pinta

Adults: 1.2 million units I.M. as a single dose

➣ Prophylaxis of rheumatic fever and glomerulonephritis

Adults: After acute attack, 1.2 million units I.M. q month or 600,000 units q 2 weeks

Contraindications

• Hypersensitivity to penicillins, beta-lactamase inhibitors (piperacillin/tazobactam), or benzathine

Precautions

Use cautiously in:
• severe renal insufficiency, significant allergies, asthma
• pregnant or breastfeeding patients.

Administration

• Before giving, ask patient about allergy to penicillin, beta-lactamase inhibitors, and benzathine. Be aware that cross-sensitivity to cephalosporins and imipenem also may occur.
• Inject deep I.M. into upper outer quadrant of buttock in adult or midlateral thigh in infant or small child. Don't inject into gluteal muscle in child younger than age 2. Rotate injection sites with repeated doses.
• If using prefilled syringes, follow manufacturer's instructions carefully.
☞ Keep epinephrine and emergency equipment at hand in case of anaphylaxis.
• Be aware that Hoigne's syndrome (transient bizarre behavior and neurologic reactions) may immediately follow I.M. injection.
• Know that in syphilis treatment, Jarisch-Hersheimer reaction (fever, chills, headache, sweating, malaise, hypotension or hypertension) may occur 2 to 12 hours after therapy begins and usually subsides within 24 hours.

Route	Onset	Peak	Duration
I.M.	Delayed	Dose dependent	Dose dependent

Adverse reactions

CNS: headache, lethargy, hallucinations, anxiety, neuropathy, fatigue, nervousness, tremors, euphoria, asthenia, Hoigne's syndrome, cerebrovascular accident, seizures, coma

CV: hypotension, pulmonary hypertension, vasodilation, vasovagal reaction, syncope, palpitations, tachycardia, cardiac arrest, pulmonary embolism

EENT: blurred vision, vision loss, laryngeal edema

GI: nausea, vomiting, diarrhea, epigastric distress, abdominal pain, colitis, blood in stool, glossitis, pseudomembranous colitis

GU: hematuria, proteinuria, urogenic bladder, erectile dysfunction, priapism, nephropathy, renal failure

Hematologic: hemolytic anemia, leukopenia, thrombocytopenia

Metabolic: hypernatremia, hyperkalemia

Respiratory: dyspnea, hypoxia, apnea, pulmonary embolism

Skin: rash, urticaria, sweating

Other: fever, superinfection, injection site reactions and pain, Jarisch-Hersheimer reaction, anaphylaxis, serum sickness

Interactions

Drug-drug. Aspirin, probenecid: increased penicillin blood level

Erythromycins, tetracyclines: decreased antimicrobial activity of penicillin

Hormonal contraceptives: decreased contraceptive efficacy

Drug-diagnostic tests. Alanine aminotransferase, blood urea nitrogen, creatinine, eosinophils, granulocytes, hemoglobin, platelets, potassium, white blood cells: increased levels

Direct Coombs' test: positive result

Sodium: decreased level

Urine glucose, urine protein: false-positive results

Patient monitoring

☞ Watch closely for anaphylaxis and serum sickness.
• In long-term therapy, monitor electrolyte levels and CBC with white cell differential; watch for electrolyte imbalances and blood dyscrasias.
• Assess neurologic status, especially for seizures and decreasing level of consciousness.
☞ Watch for evidence of superinfection and pseudomembranous colitis.

Patient teaching

☞ Teach patient to recognize anaphylaxis symptoms and to contact emergency medical services immediately if these occur.
☞ Tell patient drug may cause diarrhea. Instruct him to immediately report severe, persistent diarrhea, and fever.
• Urge patient to complete entire course of therapy as prescribed, even after symptoms improve.
• Advise patient to contact prescriber if infection symptoms get worse.
• Tell female patient that drug may make hormonal contraceptives ineffective. Advise her to use barrier birth control if she wishes to avoid pregnancy.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.