From the FDA Drug Label
ADVERSE REACTIONS Although the incidence of reactions to oral penicillins has been reported with much less frequency than following parenteral therapy, it should be remembered that all degrees of hypersensitivity, including fatal anaphylaxis, have been reported with oral penicillin The most common reactions to oral penicillin are nausea, vomiting, epigastric distress, diarrhea, and black hairy tongue. The hypersensitivity reactions reported are skin eruptions (maculopapular to exfoliative dermatitis), urticaria and other serum sickness-like reactions, laryngeal edema and anaphylaxis. Fever and eosinophilia may frequently be the only reaction observed Hemolytic anemia, leukopenia, thrombocytopenia, neuropathy and nephropathy are infrequent reactions and usually associated with high doses of parenteral penicillin.
The cause of encephalopathy due to Penicillin is not directly stated in the provided drug label. However, it does mention neuropathy as an infrequent reaction, usually associated with high doses of parenteral penicillin.
- Key points:
- No direct information on encephalopathy
- Neuropathy is mentioned as a possible reaction
- Based on the available information, no conclusion can be drawn about the cause of encephalopathy due to Penicillin 1.
From the Research
Penicillin-induced encephalopathy is a rare but serious neurological complication that can occur with penicillin administration, particularly at high doses or in patients with renal impairment, and is caused by the drug's ability to cross the blood-brain barrier and inhibit GABA-mediated neurotransmission, as reported in a recent study 2. The condition is characterized by clinical manifestations such as confusion, disorientation, myoclonus, seizures, and in severe cases, coma.
- Risk factors for penicillin-induced encephalopathy include renal dysfunction, high-dose therapy (particularly above 20 million units daily), advanced age, and pre-existing neurological conditions.
- The presence of coexistent renal compromise should heighten the vigilance of clinicians, as noted in a case report 3.
- Symptoms usually resolve within 24-72 hours after discontinuation of the medication.
- Alternative antibiotics should be considered based on the infection being treated and antimicrobial susceptibility.
- Prevention strategies include appropriate dosing based on renal function, monitoring drug levels when possible, and being vigilant for early neurological symptoms in high-risk patients, as discussed in a review of antibiotic-associated encephalopathy 4. If penicillin-induced encephalopathy is suspected, the medication should be immediately discontinued and supportive care initiated, as there is no specific antidote, but hemodialysis may be considered in severe cases to remove the drug from circulation, as noted in a study on penicillin encephalopathy 5.