Benzyl Penicillin
Plain, Medium & Narrow-spectrum Penicillin · Narrow-spectrum penicillin
Indications
Infections caused by some gram-positive organisms, some gram-negative organisms such as Neisseria gonorrhoea.
Dosage
Adults: IM/IV: 2-24 MIU/day in divided doses every 4 hr. Neurosyphilis: 18-24 MIU/day in divided doses every 3-4 hr for 10-14 days. Children: IM/IV: 100,000 to 250,000 units/kg/day in divided doses every 4-6 hr. Severe infections, up to 400,000 units/kg/day in divided doses every 4-6 hr; max 24 MIU/day.
Administration
Administer by IV intermittent infusion over 15-60 min at a final concentration for administration of 100,000-500,000 units/mL. A final concentration of 50,000 units/mL infused over 15-30 min is recommended for neonates and infants. Compatibility: Sodium salts compatible in D5W, NS. Stability: Penicillin potassium is stable at room temperature. Reconstituted solution is stable for 7 days when refrigerated at 2°C-15°C. Penicillin potassium for IV infusion in NS or D5W solution is stable for 24 hours at room temperature.
Adverse Effects
Anaphylaxis. Glossitis, stomatitis, gastritis, sore throat, dry mouth, furry tongue. Anaemias. Haemorrhagic manifestation. Interstitial nephritis (e.g. oliguria, hematuria). Nephrotoxicity. Jarisch-Herxheimer reaction in patients undergoing treatment for syphilis or neurosyphilis, hypersensitivity, GI upset, pseudomembranous colitis in patients who develop persistent diarrhoea.
Risk Factor (Pregnancy/Lactation)
Pregnancy: No evidence of risk in humans. Lactation: Caution advised or effect undetermined. Contraindications: History of previous hypersensitivity reaction to penicillins and/or cephalosporins. Do not inject parenteral solutions into or near an artery or nerve. Precautions: Streptococcal infection: Therapy must be sufficient to eliminate the organism (a minimum of ten days). Otherwise the sequela of streptococcal disease (endocarditis, rheumatic fever) may occur. Avoid small ineffective doses of penicillin as resistant organisms are more likely to emerge. Serious fatal immediate hypersensitivity (anaphylactoid) reactions have been reported.
Interactions
Concurrent administration of bacteriostatic antibiotics (e.g. erythromycin, tetracycline) may diminish the bactericidal effects of penicillins. Probenecid prolongs penicillin blood levels. Oral contraceptives may be rendered less effective & an increased incidence of breakthrough bleeding may occur when administered with ampicillin or penicillin V.
Advice to Patient
This medication is administered by injection or infusion. Inform prescriber if diarrhoea occurs, even 2 months or more after penicillin therapy ends. Contact prescriber if there is burning/redness/swelling/pain at infusion site or if there is difficulty in swallowing or breathing, chest tightness, hives, rash, swelling of mouth or lips, chills, fever, unhealed sores, white plaques in vagina or mouth, fatigue, purulent vaginal discharge. Take sufficient amount of fluids (2-3 litres per day) to maintain hydration, unless restricted by the prescriber. If you are taking this medication for sexually transmitted disease, your partner should also be treated.
Pharmacokinetics
Half-life elimination: Neonates: <6 days of age: 3.1 hrs. =14 days of age: 1.4 hrs. Adults: Normal renal function: 31-50 mins. End-stage renal disease (ESRD): 6-20 hrs. Time to peak, serum: IV: Immediately after infusion. Excretion: Urine.
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Compiled by Healify Pharmacy from published drug references. How we compile it →
Always consult a pharmacist or doctor.