Pfizerpen Side Effects

Generic name: penicillin g potassium

Medically reviewed by Drugs.com. Last updated on Apr 21, 2024.

Note: This document provides detailed information about Pfizerpen Side Effects associated with penicillin g potassium. Some dosage forms listed on this page may not apply specifically to the brand name Pfizerpen.

Applies to penicillin g potassium: injectable powder for injection, intravenous solution.

Important warnings This medicine can cause some serious health issues

Follow all directions on your medicine label and package.

Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Get emergency medical help if you have any of these signs of an allergic reaction while taking penicillin g potassium (the active ingredient contained in Pfizerpen) hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• the first sign of any skin rash, no matter how mild;

• red or scaly skin;

• fever, chills, swollen glands, muscle or joint pain, fast heartbeats, general ill feeling;

• a light-headed feeling, like you might pass out;

• severe stomach pain, diarrhea that is watery or bloody;

• little or no urinating;

• bruising, severe tingling, numbness, pain, muscle weakness;

• seizure (convulsions); or

• unusual changes in mood or behavior.

Common side effects may include:

• mild diarrhea;

• headache;

• black or hairy tongue; or

• pain, swelling, bruising, or irritation around the IV needle.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For healthcare professionals

Applies to penicillin g potassium: injectable powder for injection, intravenous solution.

Hypersensitivity adverse events

• Frequency not reported: Allergic reactions, immediate allergic reactions (ranged from urticaria, pruritus to angioneurotic edema, laryngospasm, bronchospasm, hypotension, vascular collapse, death), accelerated immediate allergic reaction (included urticaria, pruritus, fever; occasionally, laryngeal edema), delayed allergic reactions (manifestations included serum sickness-like symptoms, i.e., fever, malaise, urticaria, myalgia, arthralgia, abdominal pain, various skin rashes [ranging from maculopapular eruptions to exfoliative dermatitis]), hypersensitivity myocarditis, eosinophilia, allergic vasculitis, asthenia, pain, reactions resembling serum sickness (including chills, fever, edema, arthralgia, prostration), anaphylaxis (severe and occasionally fatal)^[Ref]

Allergic reactions have been reported with all penicillins and the incidence ranged from 0.7% to 10% in various studies. Hypersensitivity reactions with penicillin were more common and more serious with IV therapy but have also been reported with oral therapy. An initial sensitizing exposure was required to stimulate the production of antigen-specific IgE before clinical manifestations of hypersensitivity are seen on the second exposure. There are numerous "hidden" environmental or occupational exposures to penicillin including in utero exposure, breast milk exposure, and occupational exposure.

Immediate allergic reactions generally occurred within 20 minutes of use; accelerated immediate reactions have occurred 20 minutes to 48 hours after use. Immediate anaphylactic reactions were very rare and generally occurred after parenteral therapy; however, a few cases of anaphylaxis have been reported after oral therapy. Delayed allergic reactions to penicillin have been reported within 1 to 2 weeks after therapy was started.^[Ref]

Dermatologic

• Frequency not reported: Rash, urticaria, contact dermatitis

Beta-lactam antibiotics:

• Frequency not reported: Severe cutaneous adverse reactions (including Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms [DRESS syndrome], acute generalized exanthematous pustulosis)^[Ref]

Contact dermatitis has been reported in those who prepared penicillin solutions.^[Ref]

Gastrointestinal

• Frequency not reported: Clostridioides difficile-associated diarrhea, pseudomembranous colitis, nausea, vomiting, diarrhea, stomatitis, black or hairy tongue, other symptoms of gastrointestinal (GI) irritation^[Ref]

Onset of pseudomembranous colitis symptoms have been reported during or after antibacterial therapy.

Nausea, vomiting, diarrhea, stomatitis, black or hairy tongue, and other symptoms of GI irritation have been reported, especially during oral therapy.^[Ref]

Metabolic

• Frequency not reported: Electrolyte disturbances (hyperkalemia), potassium poisoning (signs included hyperreflexia, convulsions, coma)^[Ref]

Serious and even fatal electrolyte disturbances (i.e., hyperkalemia) have been reported with large IV doses since 1 million units of this drug contains 1.68 mEq of potassium ion.

Severe or fatal potassium poisoning has been reported in patients receiving continuous IV therapy in high doses (10 million to 100 million units/day), especially when renal insufficiency was present.^[Ref]

Nervous system

• Frequency not reported: Neurotoxic reactions (including hyperreflexia, myoclonic twitches, seizures, coma), neuropathy, severe neurologic reactions (including myoclonus, seizures, auditory and visual hallucinations, decreased mentation), neurovascular damage, headache, tremor, confusion, agitation, aseptic meningitis, coma^[Ref]

Neurotoxic reactions have been reported after massive IV doses were administered and were more likely in patients with renal dysfunction.

Neuropathy, which was usually associated with high IV dosage, has been reported.

Severe neurologic reactions have been reported with high dose penicillin therapy or in patients with renal dysfunction; such reactions were most often seen with penicillin doses of 18 million to 80 million units daily. Neurologic reactions occurred frequently in patients with renal dysfunction. These reactions frequently abated after discontinuation of penicillin. In several cases, penicillin was restarted at a lower dose with no further sequelae. In 1 review, the authors found that cerebral spinal fluid (CSF) penicillin levels were higher in patients with seizures than in those without. CSF penicillin levels ranged from 12 to 61 units/mL in the seizure group with the highest CSF levels, compared to 7.8 units/mL in the group without seizures.^[Ref]

Hematologic

• Frequency not reported: Neutropenia, Coombs-positive hemolytic anemia, bleeding diathesis secondary to platelet dysfunction, eosinophilia, thrombocytopenia, hemolytic anemia, anemia, leukopenia^[Ref]

Neutropenia resolved after penicillin was discontinued.

Coombs-positive hemolytic anemia (an uncommon reaction) was reported in patients treated with greater than 10 million units/day of IV penicillin G and who previously received large doses of the drug.

A bleeding diathesis secondary to platelet dysfunction has been associated with large doses of penicillin.

Hemolytic anemia, leukopenia, and thrombocytopenia have been reported and were usually associated with high IV dosage.^[Ref]

Local

• Frequency not reported: Injection site pain with IV administration, phlebitis, thrombophlebitis^[Ref]

Immunologic

• Frequency not reported: Jarisch-Herxheimer reaction (characterized by fever, chills, myalgias, headache, exacerbation of cutaneous lesions, tachycardia, hyperventilation, vasodilation with flushing, mild hypertension)^[Ref]

The Jarisch-Herxheimer reaction has been reported during penicillin therapy in patients with syphilis or other spirochaetal infections. The reaction has started 1 to 2 hours after initiation of therapy and has stopped within 12 to 24 hours. The Herxheimer reaction was thought to be due to the release of heat-stable pyrogen from spirochetes.^[Ref]

Renal

• Frequency not reported: Renal tubular damage, interstitial nephritis, increased BUN/serum urea nitrogen, increased creatinine, renal failure, nephropathy^[Ref]

Renal tubular damage and interstitial nephritis have been reported with large IV doses of penicillin G; symptoms of this reaction included fever, rash, eosinophilia, proteinuria, eosinophiluria, hematuria, and increased serum urea nitrogen and resolved in most patients after penicillin G was discontinued.

Nephropathy has been reported and was usually associated with high IV dosage.^[Ref]

Genitourinary

• Frequency not reported: Hematuria, proteinuria, eosinophiluria^[Ref]

Other

• Frequency not reported: Fever^[Ref]

Hepatic

• Frequency not reported: Increased AST, reversible hepatotoxicity, jaundice, cholestasis (including prolonged), liver dysfunction, abnormal liver function tests^[Ref]

A 28-year-old female developed jaundice, fever, epidermolysis, abnormal liver function tests, and cholestasis several days after receiving a single IM penicillin dose. Her liver dysfunction continued for up to 18 months. She had taken acetaminophen concurrently but denied alcohol use.^[Ref]

Cardiovascular

• Frequency not reported: Cardiac arrhythmias, cardiac arrest^[Ref]

Further information

Pfizerpen side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

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