Generic
Phenoxymethyl Penicillin
30 brands available in the market
At a glance
Phenoxymethyl Penicillin (Penicillin V) is an antibiotic used for bacterial infections of the ear, nose, throat, lower respiratory tract, skin, and soft tissues. It is also used for prophylaxis of rheumatic fever and prevention of infection after dental and oral surgical procedures in high-risk patients.
Description
Phenoxymethyl penicillin or penicillin V is acid-stable and absorbed from the upper part of the small intestine. It inhibits biosynthesis of cell wall mucopeptide, exerting bactericidal action against sensitive organisms. It has a distinct advantage over penicillin G in resistance to inactivation by gastric acid.
Indications
- Ear, nose, and throat infections (tonsillitis, pharyngitis, laryngitis, otitis media, sinusitis)
- Lower respiratory tract infections (bronchitis, pneumonia, bronchopneumonia)
- Group A beta-hemolytic streptococcal infections (scarlet fever, erysipelas, rheumatic fever)
- Skin infections (pyodermia, furunculosis, phlegmon, erysipeloid, erythema migrans)
- Bacterial lymphadenitis and lymphangitis
- Infections of the buccal cavity, gums, or jaws
- Prophylaxis of scarlet fever
- Prevention of rheumatic fever recurrences
- Prophylaxis of infection after dental and oral surgical procedures in high-risk patients
Therapeutic class
Narrow spectrum penicillin
Pharmacological class
Penicillin (Beta-lactam Antibiotic)
Pharmacology
Phenoxymethyl penicillin is acid-stable and absorbed from the small intestine. It inhibits cell wall mucopeptide biosynthesis, exerting bactericidal action. It is effective against sensitive organisms and most effective during active multiplication. It has a distinct advantage over penicillin G in resistance to gastric acid inactivation.
Mechanism of action
Kills bacteria by inhibiting bacterial cell wall synthesis.
Dosage
Adult Dose (Oral):
- General infections: 250-500 mg every 6 hours
- Rheumatic fever prophylaxis: 250 mg twice daily
- Streptococcal infections (scarlet fever, erysipelas): 125-250 mg every 6-8 hours for 10 days
- Pneumococcal infections (otitis media): 250-500 mg every 6 hours until afebrile for at least 2 days
- Fusospirochetosis/Staphylococcal infections: 250-500 mg every 6-8 hours
Pediatric Dose (Oral):
- Children: 25-50 mg/kg/day every 6 hours
- Children (>1 year): 125-250 mg every 6 hours
- Infants (<1 year): 62.5-125 mg every 6 hours
Administration
- Take on an empty stomach (at least 1 hour before or 2 hours after meals)
- Swallow tablet whole; do not chew
- Shake bottle well before each use of syrup
- Complete the full course of treatment
Missed dose
If you miss a dose, take it as soon as you remember; skip if it's almost time for next dose; do not double the dose.
Side effects
Common Side Effects:
- Skin rashes (urticaria, morbilliform or scarlatiniform rashes)
- Pruritus
- Eosinophilia
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain
- Gastrointestinal disturbances
- Pseudomembranous colitis
- Anaphylactic reactions
- Angioneurotic edema
- Laryngeal edema
- Bronchial spasm
- Shock
- Leukopenia, granulocytopenia, agranulocytosis
- Hemolytic anemia
- Thrombocytopenia
- Pancytopenia
- Myelosuppression
- Drug-induced aseptic meningitis
- Encephalopathy (in overdose or renal impairment)
Precautions & warnings
- Consider cross-allergy with cephalosporins
- Do not use in patients with severe GI disorders (with vomiting and diarrhea)
- Prolonged use may lead to proliferation of resistant organisms
- Consider sugar content in syrup for diabetic patients
- Risk of encephalopathy (in overdose or renal impairment)
Contraindications
- Hypersensitivity to penicillins or any excipient
- Severe gastrointestinal disorders with vomiting and diarrhea
Drug interactions
- Food: Reduces absorption rate; take on empty stomach
- Methotrexate: Increased serum levels and toxic effects
- Bacteriostatic chemotherapeutics/antibiotics (tetracyclines, chloramphenicol): May attenuate or abolish penicillin activity
- Probenecid: Inhibits renal excretion, increasing serum levels
- Indomethacin, phenylbutazone, salicylates, sulfinpyrazone: Elevated and prolonged serum levels
- Oral contraceptives: Effectiveness uncertain (reduced estrogen/progestogen levels)
- Aminoglycosides (neomycin): Reduced absorption
- Oral anticoagulants (warfarin): Prolonged prothrombin time/INR
Food interactions
Take on an empty stomach for maximum absorption; alcohol consumption does not cause harmful effects.
Use in pregnancy
Use in Pregnancy: Generally considered safe during pregnancy; animal studies have shown low or no adverse effects; limited human studies available.
Pregnancy Category: B — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: Safe during breastfeeding; human studies show insignificant transfer to breast milk and no harm to the baby; diarrhea and yeast colonization may occur in the infant.
Pediatric use
Pediatric dosing based on age and weight; consult your doctor.
Geriatric use
Caution required in elderly patients; consult your doctor.
Renal / hepatic impairment
Renal Impairment: Caution in kidney disease; dose adjustment may be needed; consult your doctor.
Hepatic Impairment: Limited information on use in liver disease; consult your doctor.
Overdose effects
Phenoxymethylpenicillin has low toxicity; no acute toxicity from single multiple therapeutic dose. Risk of encephalopathy in overdose; treatment: discontinue medication; hemodialysis can eliminate phenoxymethylpenicillin.
Storage conditions
Store in a cool and dry place, protected from light.
Chemical structure
Phenoxymethyl Penicillin