Pfizerpen G 5mu Inj, 1 Vial

Penicillin G is a bactericidal 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 (transpeptidation). This binding prevents the cross-linking of peptidoglycan chains, leading to a defective cell wall, increased osmotic pressure, and ultimately cell lysis and bacterial 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, such as:
+ 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
Note: In rare cases, allergic reactions can be fatal.
Signs of high potassium levels, including:
+ 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
Fast 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 it's severe, watery, or bloody (may be a sign of C. diff-associated diarrhea, a potentially life-threatening condition)

If you experience any of these symptoms, contact your doctor immediately.

Additional Side Effects of This Medication

While many people may not experience side effects or only have mild ones, it's essential to be aware of the following possible side effects:

Diarrhea
Upset stomach or vomiting
Mouth irritation or mouth sores
Change in tongue color
* Irritation at the injection site (if administered via muscle injection)

If you're concerned about any side effects or if they persist, contact your doctor for guidance.

Reporting Side Effects

If you experience any side effects, you can report them to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch. Your doctor can also provide advice on managing side effects.

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
+ Sulfonamides (e.g., sulfamethoxazole)
+ Tetracyclines (e.g., 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 interactions with this medication. To ensure your safety, it is crucial to:

Inform your doctor and pharmacist about all medications you are taking, including:
+ Prescription medications
+ Over-the-counter (OTC) medications
+ Natural products
+ Vitamins
Share information about any existing health problems.
Verify that it is safe to take this medication with all your other medications and health conditions.
Never start, stop, or change the dose of any medication without first consulting your doctor.

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 exceed the prescribed duration of treatment, as this may increase the risk of a second infection. High doses of this medication can lead to severe and potentially life-threatening electrolyte imbalances. Discuss any concerns with your doctor.

If you have diabetes and regularly test your urine glucose levels, consult 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 treatment. Be aware that this medication can cause severe skin reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious conditions that may 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 other areas of skin; fever; chills; body aches; shortness of breath; or swollen glands.

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

• Methotrexate (increased methotrexate toxicity due to decreased renal clearance)
• Tetracyclines (may antagonize bactericidal effect of penicillin G)

• Probenecid (increases penicillin G plasma concentrations and prolongs half-life by inhibiting renal tubular secretion)
• Oral contraceptives (theoretical reduction in efficacy, though clinical significance is debated)
• Aminoglycosides (physical incompatibility in solution; may inactivate aminoglycosides if mixed directly)

• Skin rash
• Hives
• Itching
• Swelling of face/lips/tongue/throat
• Difficulty breathing or swallowing
• Wheezing
• Severe diarrhea (especially if bloody or watery)
• Abdominal cramps
• Fever
• Sore throat
• Unusual bleeding or bruising
• Seizures (rare, with very high doses or renal impairment)

Penicillin G is generally considered safe for use during pregnancy (Pregnancy Category B). Studies in animals have not shown fetal harm, and adequate and well-controlled studies in pregnant women have not demonstrated a risk to the fetus. It is commonly used for infections like syphilis in pregnant women.

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 (e.g., rash).

Dosing must be carefully calculated based on weight, age, and the specific infection. Neonates and young infants have immature renal function, requiring lower doses and/or extended dosing intervals to prevent accumulation and toxicity. Close monitoring for adverse effects is essential.

Elderly patients are more likely to have decreased renal function, which can lead to reduced clearance and increased plasma concentrations of penicillin G. Dose adjustments based on creatinine clearance are often necessary. Monitor for signs of neurotoxicity and electrolyte imbalances.

• Always confirm penicillin allergy status before administration. A history of penicillin allergy should be thoroughly investigated, as many reported allergies are not true IgE-mediated reactions.
• For severe infections, continuous IV infusion of penicillin G can maintain more consistent therapeutic drug levels and may be preferred over intermittent boluses.
• High doses of potassium penicillin G can lead to significant potassium load, especially in patients with renal impairment, requiring electrolyte monitoring.
• Penicillin G is not effective against beta-lactamase producing bacteria, including many strains of Staphylococcus aureus and Gram-negative bacilli.
• Ensure proper administration technique for IM injections (deep IM) to minimize pain and local reactions.

• Other beta-lactam antibiotics (e.g., ampicillin, amoxicillin, cefazolin, ceftriaxone)
• Macrolides (e.g., azithromycin, erythromycin) for penicillin-allergic patients or specific infections
• Vancomycin (for resistant Gram-positive infections, e.g., MRSA)
• Clindamycin (for anaerobic infections or certain 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 or take someone else's medication. 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, do not flush medications down the toilet or pour them down the drain. If you are unsure about the correct disposal method, consult your pharmacist, who can also inform you about potential drug take-back programs in your area. Some medications may come with an additional patient information leaflet, which your pharmacist can provide. 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 medical attention. Be prepared to provide information about the medication taken, the amount, and the time it occurred.