Penicillin G Sodium 5 Million Units
It is used to treat bacterial infections.
Drug Class
Antibiotic
Pharmacologic Class
Beta-lactam antibiotic; Natural penicillin
Pregnancy Category
Category B
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
Penicillin G Sodium is an antibiotic used to treat many different types of bacterial infections. It works by killing the bacteria that cause the infection. It is given as an injection, either into a vein (IV) or a muscle (IM).
How to Use This Medicine
Taking Your Medication Correctly
To ensure safe and effective use, take this medication exactly as directed by your doctor. Carefully read all the information provided to you and follow the instructions closely. This medication can be administered in two ways: as an injection into a muscle (intramuscularly) or as an infusion into a vein (intravenously) over a specified period of time.
Storing and Disposing of Your Medication
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist to determine the proper storage procedure.
Missing a Dose
If you miss a dose, contact your doctor promptly to receive guidance on what to do next.
To ensure safe and effective use, take this medication exactly as directed by your doctor. Carefully read all the information provided to you and follow the instructions closely. This medication can be administered in two ways: as an injection into a muscle (intramuscularly) or as an infusion into a vein (intravenously) over a specified period of time.
Storing and Disposing of Your Medication
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist to determine the proper storage procedure.
Missing a Dose
If you miss a dose, contact your doctor promptly to receive guidance on what to do next.
Lifestyle & Tips
- Complete the full course of treatment as prescribed, even if you start feeling better, to prevent the infection from returning and to reduce the risk of antibiotic resistance.
- Report any signs of allergic reaction immediately, such as rash, itching, swelling, or difficulty breathing.
- Inform your healthcare provider about all medications you are taking, including over-the-counter drugs, supplements, and herbal products.
Available Forms & Alternatives
Available Strengths:
- Penicillin Vk 125mg/5ml Soln 100ml
- Penicillin Vk 125mg/5ml Soln 200ml
- Penicillin G Sodium 5 Million Units
- Penicillin Vk 250mg/5ml Soln 100ml
- Penicillin Vk 250mg/5ml Soln 200ml
- Penicillin Gk 5mu Inj, 1 Vial
- Penicillin Gk 20mu Inj, 1 Vial
- Penicillin Vk 250mg Tablets
- Penicillin Vk 500mg Tablets
- Penicillin Gk 5mu Inj, 1 Vial
- Penicillin Vk 500mg Tablets
- Penicillin Vk 250mg Tablets
- Penicillin Vk 250mg Tablets
- Penicillin Gk 20mu Inj, 1 Vial
- Penicillin Gk 20mu Inj, 1 Vial
Dosing & Administration
Adult Dosing
Standard Dose:
2 to 24 million units/day IV or IM in divided doses every 4-6 hours, depending on infection severity and type.
Dose Range:
2000000 - 24000000 mg
Condition-Specific Dosing:
Severe infections (e.g., endocarditis, meningitis):
12 to 24 million units/day IV in divided doses every 4-6 hours.
Syphilis (neurosyphilis):
3-4 million units IV every 4 hours for 10-14 days.
Pediatric Dosing
Neonatal:
50,000 to 100,000 units/kg/day IV/IM in divided doses (e.g., every 8-12 hours), adjusted based on age (postnatal and gestational) and infection.
Infant:
100,000 to 250,000 units/kg/day IV/IM in divided doses every 4-6 hours, depending on infection severity.
Child:
100,000 to 400,000 units/kg/day IV/IM in divided doses every 4-6 hours (max 24 million units/day), depending on infection severity.
Adolescent:
Adult dosing generally applies for severe infections (e.g., 12-24 million units/day IV in divided doses).
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment usually needed (CrCl > 50 mL/min).
Moderate:
Reduce dose by 25-50% or extend dosing interval (CrCl 10-50 mL/min). For example, 2-3 million units every 8-12 hours.
Severe:
Significant dose reduction required (CrCl < 10 mL/min). For example, 1-2 million units every 8-12 hours, or 1-2 million units every 12-18 hours for very severe impairment.
Dialysis:
Hemodialysis removes penicillin G. Administer dose after dialysis session. For example, 1-2 million units after each dialysis session.
Hepatic Impairment:
Mild:
No adjustment.
Moderate:
No adjustment.
Severe:
No adjustment.
Pharmacology
Mechanism of Action
Penicillin G is a bactericidal antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs) located inside the bacterial cell wall. This binding prevents the cross-linking of peptidoglycan units, which are essential for the structural integrity of the cell wall, leading to osmotic instability and bacterial cell lysis.
Pharmacokinetics
Absorption:
Bioavailability:
Not applicable (parenteral administration)
Tmax:
IV: Rapid (minutes); IM: 30-60 minutes
FoodEffect:
Not applicable (parenteral administration)
Distribution:
Vd:
0.3-0.4 L/kg
ProteinBinding:
45-65%
CnssPenetration:
Limited (unless meninges are inflamed, then adequate)
Elimination:
HalfLife:
0.4-0.9 hours (normal renal function)
Clearance:
Renal clearance is high, primarily via tubular secretion and glomerular filtration.
ExcretionRoute:
Renal (primarily unchanged drug)
Unchanged:
50-90%
Pharmacodynamics
OnsetOfAction:
Rapid (within minutes of IV administration)
PeakEffect:
Within minutes (IV); 30-60 minutes (IM)
DurationOfAction:
4-6 hours (due to short half-life, requiring frequent dosing)
Safety & Warnings
Side Effects
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 medical attention immediately:
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
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, especially if it is severe, bloody, or watery (see below for more information on diarrhea)
Important Information About Diarrhea:
Diarrhea is a common side effect of antibiotics. However, in rare cases, a severe form of diarrhea called Clostridioides difficile-associated diarrhea (CDAD) can occur. CDAD may happen during or several months after taking antibiotics. If you experience stomach pain, cramps, or severe diarrhea, contact your doctor immediately.
Injection-Specific Side Effects:
If you receive this medication via injection into a muscle, there is a risk of nerve damage. This can be long-lasting. If you experience numbness, tingling, or weakness, contact your doctor right away.
Other Possible Side Effects:
Most people do not experience significant side effects, but some may occur. If you notice any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Diarrhea
Upset stomach or vomiting
Mouth irritation or mouth sores
Change in tongue color
* Irritation at the injection site
Reporting Side Effects:
This is not an exhaustive list of possible 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.
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 medical attention immediately:
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
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, especially if it is severe, bloody, or watery (see below for more information on diarrhea)
Important Information About Diarrhea:
Diarrhea is a common side effect of antibiotics. However, in rare cases, a severe form of diarrhea called Clostridioides difficile-associated diarrhea (CDAD) can occur. CDAD may happen during or several months after taking antibiotics. If you experience stomach pain, cramps, or severe diarrhea, contact your doctor immediately.
Injection-Specific Side Effects:
If you receive this medication via injection into a muscle, there is a risk of nerve damage. This can be long-lasting. If you experience numbness, tingling, or weakness, contact your doctor right away.
Other Possible Side Effects:
Most people do not experience significant side effects, but some may occur. If you notice any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Diarrhea
Upset stomach or vomiting
Mouth irritation or mouth sores
Change in tongue color
* Irritation at the injection site
Reporting Side Effects:
This is not an exhaustive list of possible 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.
Seek Immediate Medical Attention If You Experience:
- Severe allergic reaction (anaphylaxis): difficulty breathing, swelling of face/throat, hives, rapid heartbeat, dizziness.
- Severe diarrhea (watery or bloody stools), which may indicate C. difficile infection.
- Seizures or other neurological symptoms (especially with high doses or kidney problems).
- Unusual bleeding or bruising.
- Fever, chills, sore throat (may indicate new infection or blood disorder).
Before Using This Medicine
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 symptoms you experienced.
If you are currently taking chloramphenicol, erythromycin, sulfa-drugs (like sulfamethoxazole), or tetracycline drugs (like doxycycline). If you are unsure, consult your doctor or pharmacist for guidance.
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 the medications you are taking, including prescription and over-the-counter drugs, natural products, and vitamins.
Discuss all your health problems with your doctor and pharmacist.
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 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 symptoms you experienced.
If you are currently taking chloramphenicol, erythromycin, sulfa-drugs (like sulfamethoxazole), or tetracycline drugs (like doxycycline). If you are unsure, consult your doctor or pharmacist for guidance.
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 the medications you are taking, including prescription and over-the-counter drugs, natural products, and vitamins.
Discuss all your health problems with your doctor and pharmacist.
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.
Precautions & Cautions
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 take 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 tests to use, as this medication may affect the results.
This drug can interfere with certain laboratory tests, so it is crucial to inform your doctor and laboratory personnel that you are taking this medication. Additionally, if you are on a low-sodium or low-potassium diet, discuss this with your doctor to ensure safe management of your condition.
Be aware that this medication can cause severe skin reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious reactions, which can also affect internal organs. These reactions can be life-threatening. 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 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 of this medication to both you and your baby.
Do not take 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 tests to use, as this medication may affect the results.
This drug can interfere with certain laboratory tests, so it is crucial to inform your doctor and laboratory personnel that you are taking this medication. Additionally, if you are on a low-sodium or low-potassium diet, discuss this with your doctor to ensure safe management of your condition.
Be aware that this medication can cause severe skin reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious reactions, which can also affect internal organs. These reactions can be life-threatening. 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 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 of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Neurological toxicity (e.g., seizures, confusion, hallucinations, myoclonus), especially in patients with renal impairment or receiving very high doses.
- Electrolyte imbalances (e.g., hypernatremia, hypokalemia) due to the sodium content of the drug.
- Hypersensitivity reactions.
What to Do:
Call 1-800-222-1222 (Poison Control). Treatment is supportive and symptomatic. Hemodialysis can remove penicillin G from the blood in severe cases of toxicity.
Drug Interactions
Major Interactions
- Methotrexate (increased methotrexate levels and toxicity due to competition for renal tubular secretion)
- Tetracyclines (may antagonize bactericidal effect of penicillin G)
- Live bacterial vaccines (e.g., BCG vaccine, typhoid vaccine - may reduce efficacy)
Moderate Interactions
- Probenecid (decreases renal tubular secretion of penicillin G, increasing and prolonging plasma concentrations)
- Oral contraceptives (theoretical risk of reduced efficacy, though clinical significance is debated)
- Warfarin (potential for increased INR due to altered gut flora or displacement from protein binding, though rare)
- Aminoglycosides (physical incompatibility in solution; synergistic effect against some organisms but must be administered separately)
Monitoring
Baseline Monitoring
Renal function (BUN, creatinine)
Rationale: Penicillin G is primarily renally eliminated; baseline assessment is crucial for dose adjustment.
Timing: Prior to initiation of therapy.
Electrolytes (especially potassium, sodium)
Rationale: High doses of penicillin G sodium can contribute significant sodium load; potassium levels may be affected.
Timing: Prior to initiation of therapy.
Allergy history (especially to penicillins, cephalosporins)
Rationale: To identify potential hypersensitivity reactions.
Timing: Prior to initiation of therapy.
Routine Monitoring
Clinical response (resolution of signs/symptoms of infection)
Frequency: Daily
Target: Improvement/resolution
Action Threshold: Lack of improvement or worsening symptoms may indicate treatment failure, resistance, or alternative diagnosis.
Renal function (BUN, creatinine)
Frequency: Every 2-3 days, or more frequently in patients with renal impairment or receiving high doses.
Target: Within patient's baseline or acceptable limits.
Action Threshold: Significant increase in BUN/creatinine may necessitate dose adjustment or discontinuation.
Electrolytes (Na, K)
Frequency: Every 2-3 days, especially with high doses or in patients at risk for electrolyte imbalances.
Target: Within normal limits.
Action Threshold: Significant abnormalities (e.g., hypernatremia, hypokalemia) require intervention.
Complete Blood Count (CBC) with differential
Frequency: Weekly, or more frequently in prolonged therapy.
Target: Within normal limits.
Action Threshold: Significant leukopenia, thrombocytopenia, or eosinophilia may indicate adverse drug reaction.
Signs of hypersensitivity (rash, pruritus, fever, dyspnea)
Frequency: Daily
Target: Absence of symptoms
Action Threshold: Any sign of allergic reaction requires immediate discontinuation and management.
Symptom Monitoring
- Rash
- Itching
- Hives
- Difficulty breathing or swallowing
- Swelling of face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
- Wheezing
- Fever
- Chills
- Sore throat
- Joint pain
- Diarrhea (especially severe or bloody)
- Seizures
- Confusion
- Hallucinations
- Muscle twitching
- Numbness or tingling
Special Patient Groups
Pregnancy
Generally considered safe and effective for use during pregnancy when indicated. It is a Category B drug.
Trimester-Specific Risks:
First Trimester:
No increased risk of congenital anomalies observed in human studies.
Second Trimester:
No adverse effects reported.
Third Trimester:
No adverse effects reported.
Lactation
Penicillin G is excreted into breast milk in small amounts. Generally considered compatible with breastfeeding.
Infant Risk:
Low risk. Potential for mild gastrointestinal disturbances (e.g., diarrhea, candidiasis) or allergic sensitization in the infant, but these are rare and usually mild. Monitor infant for rash or diarrhea.
Pediatric Use
Dosing is weight-based and adjusted for age, especially in neonates and infants due to immature renal function. Close monitoring for adverse effects, particularly neurological toxicity at high doses, is important.
Geriatric Use
Elderly patients may have reduced renal function, requiring dose adjustment based on creatinine clearance. They may also be more susceptible to central nervous system adverse effects (e.g., seizures, confusion) at higher doses. Monitor renal function closely.
Clinical Information
Clinical Pearls
- Always inquire about penicillin allergy before administration. Even a history of mild rash should prompt caution and consideration of alternative agents.
- Penicillin G Sodium contains a significant amount of sodium (approximately 1.7 mEq sodium per 1 million units), which should be considered in patients on sodium-restricted diets or with heart failure/renal impairment.
- Administer IV doses slowly (over 30-60 minutes) to minimize vein irritation and potential for CNS effects with rapid infusion.
- In patients with severe renal impairment, neurological toxicity (e.g., seizures, myoclonus) is a significant risk due to accumulation of the drug. Dose adjustment is critical.
- Penicillin G is the drug of choice for many streptococcal infections, syphilis, and certain clostridial infections.
Alternative Therapies
- Other beta-lactam antibiotics (e.g., ampicillin, amoxicillin, cephalosporins)
- Macrolides (e.g., azithromycin, erythromycin) for penicillin-allergic patients (note: resistance is common for some pathogens)
- Vancomycin (for severe infections, MRSA, or severe beta-lactam allergy)
- Clindamycin (for certain anaerobic infections or penicillin-allergic patients)
Cost & Coverage
Average Cost:
Not available Not available
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (Generic)
General Drug Facts
If your symptoms or health problems do not improve or worsen over time, it is essential to contact your doctor for further evaluation and guidance.
To ensure safe use, do not share your medication with others, and never take someone else's medication. Store all medications in a secure location, out of the reach of children and pets, to prevent accidental ingestion.
Proper disposal of unused or expired medications is crucial. Do not flush them down the toilet or pour them down the drain unless specifically instructed to do so. If you are unsure about the best disposal method, consult your pharmacist for guidance. Many communities have drug take-back programs, which your pharmacist can help you locate.
Some medications may come with an additional patient information leaflet. Check with your pharmacist to see if this applies to your prescription. If you have any questions or concerns about your medication, do not hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. Be prepared to provide critical information, including the name of the medication, the amount taken, and the time it was taken, to ensure prompt and effective treatment.
To ensure safe use, do not share your medication with others, and never take someone else's medication. Store all medications in a secure location, out of the reach of children and pets, to prevent accidental ingestion.
Proper disposal of unused or expired medications is crucial. Do not flush them down the toilet or pour them down the drain unless specifically instructed to do so. If you are unsure about the best disposal method, consult your pharmacist for guidance. Many communities have drug take-back programs, which your pharmacist can help you locate.
Some medications may come with an additional patient information leaflet. Check with your pharmacist to see if this applies to your prescription. If you have any questions or concerns about your medication, do not hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. Be prepared to provide critical information, including the name of the medication, the amount taken, and the time it was taken, to ensure prompt and effective treatment.