Pfizerpen G 20mu Inj, 1vial

Penicillin G is a bactericidal beta-lactam antibiotic that inhibits bacterial cell wall synthesis. It binds to penicillin-binding proteins (PBPs) located inside the bacterial cell wall, which are enzymes involved in the final stages of peptidoglycan synthesis (transpeptidases). This binding prevents the cross-linking of peptidoglycan chains, leading to a defective cell wall, increased osmotic pressure, and ultimately cell lysis and death.

Urgent Side Effects: Seek Medical Help Right Away

Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:

Signs of an allergic reaction, including:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Rarely, allergic reactions can be fatal.
Signs of high potassium levels, such as:
+ Abnormal heartbeat
+ Confusion
+ Weakness, lightheadedness, or dizziness
+ Feeling like passing out
+ Numbness or tingling
+ Shortness of breath
Severe dizziness or fainting
Fever, chills, or sore throat
Unexplained bruising or bleeding
Feeling extremely tired or weak
Chest pain or pressure
Headache
Rapid heartbeat
Rapid breathing
Flushing
Yellowing of the skin or eyes
Muscle or joint pain
Stomach pain
Twitching
Seizures
Difficulty urinating or changes in urine output
Diarrhea (common with antibiotics), especially if severe, bloody, or watery. Rarely, a severe form called C. diff-associated diarrhea (CDAD) may occur, which can lead to life-threatening bowel problems. If you experience stomach pain, cramps, or severe diarrhea, contact your doctor immediately.

Additional Side Effects to Discuss with Your Doctor

Most people do not experience severe side effects, but some may occur. If you notice any of the following side effects, contact your doctor if they bother you or do not resolve:

Diarrhea
Upset stomach or vomiting
Mouth irritation or mouth sores
Change in tongue color
Irritation at the injection site (if given via muscle injection)
* Nerve damage (if given via muscle injection), which can cause numbness, tingling, or weakness. If you experience any of these symptoms, contact your doctor immediately.

Reporting Side Effects

If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following:

Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you are currently taking any of the following medications: chloramphenicol, erythromycin, sulfa-drugs (like sulfamethoxazole), or tetracycline drugs (like doxycycline). If you are unsure about any of these medications, consult with your doctor or pharmacist.

Please note that this is not an exhaustive list of all potential drug interactions or health problems that may affect your use of this medication.

To ensure your safety, it is crucial to inform your doctor and pharmacist about:

All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* Your complete medical history, including any health problems you have

Before starting, stopping, or changing the dose of any medication, including this one, you must consult with your doctor to confirm that it is safe to do so.

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you are taking this drug for an extended period, your doctor may recommend regular blood tests to monitor your condition.

Do not use this medication for longer than prescribed, as this can increase the risk of a second infection. High doses of this drug can cause severe and potentially life-threatening electrolyte imbalances. Discuss any concerns with your doctor.

If you have diabetes and regularly test your urine glucose, consult with your doctor to determine the most suitable testing methods to use while taking this medication. Additionally, inform your doctor and laboratory personnel that you are taking this drug, as it may affect the results of certain lab tests.

If you are following a low-sodium or low-potassium diet, discuss this with your doctor to ensure safe use of this medication. Be aware that this drug can cause severe skin reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious conditions that can also affect internal organs. These reactions can be fatal. Seek immediate medical attention if you experience symptoms such as red, swollen, blistered, or peeling skin; red or irritated eyes; sores in your mouth, throat, nose, eyes, genitals, or skin; fever; chills; body aches; shortness of breath; or swollen glands.

When administering this drug to newborns, exercise caution, as the risk of side effects may be higher in this population. If you are pregnant, plan to become pregnant, or are breastfeeding, consult with your doctor to discuss the potential benefits and risks to you and your baby.

• Methotrexate (increased methotrexate levels and toxicity due to competition for renal tubular secretion)
• Tetracyclines (may antagonize the bactericidal effect of penicillin G; avoid concomitant use)

• Probenecid (decreases renal tubular secretion of penicillin G, leading to increased and prolonged plasma concentrations)
• Oral Contraceptives (theoretical risk of reduced efficacy, though clinical evidence is weak; advise backup contraception)
• Warfarin (may enhance anticoagulant effect by altering gut flora or displacing from protein binding, monitor INR)

• Aminoglycosides (physical incompatibility in solution; administer separately)
• Live Bacterial Vaccines (e.g., typhoid vaccine; antibiotics may reduce vaccine efficacy)

• Rash
• Hives
• Itching
• Swelling of face/lips/tongue/throat
• Difficulty breathing or swallowing
• Wheezing
• Severe diarrhea (especially watery or bloody)
• Abdominal cramps
• Fever
• Sore throat
• Unusual bleeding or bruising
• Seizures
• Confusion
• Hallucinations
• Muscle twitching

Penicillin G is generally considered safe and is a commonly used antibiotic during pregnancy. It crosses the placenta but is not associated with an increased risk of birth defects.

Penicillin G is excreted into breast milk in small amounts. It is generally considered compatible with breastfeeding. Monitor the infant for potential adverse effects such as diarrhea, candidiasis (thrush, diaper rash), or allergic reactions.

Dosing must be carefully calculated based on age, weight, and renal function. Neonates and infants have immature renal function, requiring specific dosing adjustments and close monitoring. High doses can lead to neurotoxicity.

Elderly patients are more likely to have age-related decline in renal function, which necessitates careful dose adjustment based on creatinine clearance. They may also be more susceptible to central nervous system side effects (e.g., seizures) and electrolyte imbalances, especially with high doses.

• Always confirm patient allergy history before administering penicillin G, as severe hypersensitivity reactions (including anaphylaxis) can occur.
• Penicillin G is highly effective against susceptible Gram-positive bacteria (e.g., Streptococcus spp.) and some Gram-negative cocci (e.g., Neisseria meningitidis), but it is susceptible to beta-lactamase enzymes.
• For IV administration, ensure proper dilution and infusion rate to avoid vein irritation.
• High doses of potassium penicillin G can lead to significant potassium load, requiring electrolyte monitoring, especially in patients with renal impairment or those receiving other potassium-sparing agents.
• Neurotoxicity (e.g., seizures) is a rare but serious side effect, particularly in patients with renal failure, high doses, or pre-existing CNS disorders. Monitor for changes in mental status or seizure activity.
• Penicillin G is not effective against penicillinase-producing Staphylococcus aureus or most Gram-negative rods.
• Intrathecal administration is generally not recommended due to the risk of neurotoxicity.

• Other beta-lactam antibiotics (e.g., ampicillin, amoxicillin, cephalosporins, carbapenems) depending on the specific pathogen and infection site.
• Macrolides (e.g., azithromycin, erythromycin) for penicillin-allergic patients with susceptible infections.
• Vancomycin (for serious Gram-positive infections, especially MRSA or in penicillin-allergic patients where other options are not suitable).
• Clindamycin (for certain anaerobic infections or Gram-positive infections in penicillin-allergic patients).

If your symptoms or health problems persist or worsen, it is essential to contact your doctor promptly. To ensure safe use, never share your medication with others, and do not take medication prescribed for someone else. Store all medications in a secure location, out of the reach of children and pets, to prevent accidental ingestion. Dispose of unused or expired medications properly. Unless instructed to do so by a healthcare professional or pharmacist, do not flush medications down the toilet or drain. If you are unsure about the correct disposal method, consult your pharmacist, as community drug take-back programs may be available. Some medications may include an additional patient information leaflet, which can be obtained from your pharmacist. If you have any questions or concerns about your medication, discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately contact your local poison control center or seek emergency medical attention. Be prepared to provide information about the medication taken, the amount, and the time of ingestion.