Penicillin Vk 500mg Tablets
It is used to treat or prevent bacterial infections.
Drug Class
Antibiotic
Pharmacologic Class
Beta-lactam antibiotic; Penicillin
Pregnancy Category
Category B
FDA Approved
Jan 1959
DEA Schedule
Not Controlled
Overview
What is this medicine?
Penicillin V Potassium is an antibiotic used to treat various bacterial infections, such as strep throat, ear infections, and skin infections. It works by stopping the growth of bacteria.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely.
Take your medication on an empty stomach, either 1 hour before or 2 hours after meals.
If your medication causes stomach upset, you can take it with food to help alleviate this issue.
Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
To ensure your medication remains effective and safe:
Store it at room temperature in a dry place, avoiding bathrooms and areas prone to moisture.
Keep all medications in a secure location, out of the reach of children and pets.
Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist or healthcare provider.
If you have questions about disposing of your medication, consult your pharmacist. You may also have access to drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose of your medication:
Take it as soon as you remember.
However, if it's close to the time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule.
Do not take two doses at the same time or take extra doses to make up for the missed one.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely.
Take your medication on an empty stomach, either 1 hour before or 2 hours after meals.
If your medication causes stomach upset, you can take it with food to help alleviate this issue.
Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
To ensure your medication remains effective and safe:
Store it at room temperature in a dry place, avoiding bathrooms and areas prone to moisture.
Keep all medications in a secure location, out of the reach of children and pets.
Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist or healthcare provider.
If you have questions about disposing of your medication, consult your pharmacist. You may also have access to drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose of your medication:
Take it as soon as you remember.
However, if it's close to the time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule.
Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take this medication exactly as prescribed by your doctor, even if you start to feel better. Do not skip doses or stop taking it early, as this can lead to antibiotic resistance and the infection returning.
- Take on an empty stomach (1 hour before or 2 hours after meals) for best absorption, but if it causes stomach upset, you can take it with food.
- Drink plenty of fluids while taking this medication.
- Do not share this medication with others, even if they have similar symptoms.
- If you are taking oral contraceptives, consider using an additional non-hormonal birth control method while on this antibiotic and for 7 days after, as its effectiveness might be reduced (though evidence is weak).
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:
250 mg to 500 mg orally every 6 to 8 hours
Dose Range:
250 - 500 mg
Condition-Specific Dosing:
Streptococcal pharyngitis:
250 mg to 500 mg orally every 6 to 8 hours for 10 days
Pneumococcal infections:
250 mg to 500 mg orally every 6 hours
Staphylococcal infections (mild to moderate):
250 mg to 500 mg orally every 6 to 8 hours
Fusospirochetosis (Vincent's infection):
225 mg to 500 mg orally every 6 to 8 hours
Pediatric Dosing
Neonatal:
Not established (use Penicillin G for neonates)
Infant:
25-50 mg/kg/day orally divided every 6-8 hours (max 125 mg/kg/day or 3 g/day)
Child:
25-50 mg/kg/day orally divided every 6-8 hours (max 125 mg/kg/day or 3 g/day); for streptococcal pharyngitis: 250 mg orally 2-3 times daily for 10 days
Adolescent:
250 mg to 500 mg orally every 6 to 8 hours
Dose Adjustments
Renal Impairment:
Mild:
No adjustment typically needed (CrCl >50 mL/min)
Moderate:
Administer standard dose every 8-12 hours (CrCl 10-50 mL/min)
Severe:
Administer standard dose every 12-16 hours (CrCl <10 mL/min)
Dialysis:
Administer dose after dialysis on dialysis days; supplemental dose may be needed
Hepatic Impairment:
Mild:
No adjustment
Moderate:
No adjustment
Severe:
No adjustment
Pharmacology
Mechanism of Action
Penicillin V potassium is a beta-lactam 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 integrity and rigidity of the bacterial cell wall. The weakened cell wall leads to osmotic lysis and bacterial cell death.
Pharmacokinetics
Absorption:
Bioavailability:
60-75%
Tmax:
30-60 minutes
FoodEffect:
Food may decrease the rate but not the extent of absorption. It is generally recommended to take on an empty stomach (1 hour before or 2 hours after meals) for optimal absorption, but can be taken with food if GI upset occurs.
Distribution:
Vd:
0.3-0.8 L/kg
ProteinBinding:
80%
CnssPenetration:
Limited (unless meninges are inflamed)
Elimination:
HalfLife:
0.5-1 hour
Clearance:
Not available
ExcretionRoute:
Renal (tubular secretion and glomerular filtration)
Unchanged:
25-50%
Pharmacodynamics
OnsetOfAction:
Rapid
PeakEffect:
30-60 minutes (plasma concentration)
DurationOfAction:
6-8 hours (based on dosing interval)
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. Immediately contact your doctor or seek medical attention if you experience any of the following symptoms, which may indicate a serious allergic reaction:
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
In rare cases, allergic reactions can be fatal.
Additionally, antibiotics like this one can cause diarrhea, which may be mild or severe. In rare instances, a severe form of diarrhea called Clostridioides difficile-associated diarrhea (CDAD) may occur, potentially leading to life-threatening bowel problems. CDAD can develop during or several months after antibiotic treatment. If you experience any of the following symptoms, contact your doctor right away:
Stomach pain
Cramps
Very loose, watery, or bloody stools
Before treating diarrhea, consult your doctor.
Other Possible Side Effects
Like all medications, this drug can cause side effects, although many people may not experience any or may only have mild symptoms. If you are bothered by any of the following side effects or if they persist, contact your doctor or seek medical attention:
Upset stomach or vomiting
Stomach pain or diarrhea
* Black, hairy tongue
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, consult your doctor.
Reporting Side Effects
For medical advice 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.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. Immediately contact your doctor or seek medical attention if you experience any of the following symptoms, which may indicate a serious allergic reaction:
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
In rare cases, allergic reactions can be fatal.
Additionally, antibiotics like this one can cause diarrhea, which may be mild or severe. In rare instances, a severe form of diarrhea called Clostridioides difficile-associated diarrhea (CDAD) may occur, potentially leading to life-threatening bowel problems. CDAD can develop during or several months after antibiotic treatment. If you experience any of the following symptoms, contact your doctor right away:
Stomach pain
Cramps
Very loose, watery, or bloody stools
Before treating diarrhea, consult your doctor.
Other Possible Side Effects
Like all medications, this drug can cause side effects, although many people may not experience any or may only have mild symptoms. If you are bothered by any of the following side effects or if they persist, contact your doctor or seek medical attention:
Upset stomach or vomiting
Stomach pain or diarrhea
* Black, hairy tongue
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, consult your doctor.
Reporting Side Effects
For medical advice 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:
- Signs of an allergic reaction: rash, hives, itching, swelling of the face, lips, tongue, or throat, difficulty breathing or swallowing. Seek immediate medical attention.
- Severe or watery diarrhea, especially if it contains blood or mucus, which may be a sign of a serious intestinal infection (Clostridioides difficile-associated diarrhea).
- New or worsening symptoms of infection.
- White patches in your mouth or on your tongue (oral thrush) or vaginal itching/discharge (yeast infection), which can be signs of a superinfection.
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 allergic reaction and its symptoms.
Certain health conditions, including:
+ Gastrointestinal (GI) tract problems, such as an enlarged stomach or esophagus spasms
+ Severe illness
+ Diarrhea, upset stomach, or vomiting
This list is not exhaustive, and it is crucial to discuss all your health problems with your doctor.
Additionally, provide your doctor and pharmacist with a comprehensive list of all the medications you are taking, including:
Prescription and over-the-counter (OTC) drugs
Natural products
* Vitamins
Carefully review your medications and health problems with your doctor to ensure it is safe to take this medication. 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 allergic reaction and its symptoms.
Certain health conditions, including:
+ Gastrointestinal (GI) tract problems, such as an enlarged stomach or esophagus spasms
+ Severe illness
+ Diarrhea, upset stomach, or vomiting
This list is not exhaustive, and it is crucial to discuss all your health problems with your doctor.
Additionally, provide your doctor and pharmacist with a comprehensive list of all the medications you are taking, including:
Prescription and over-the-counter (OTC) drugs
Natural products
* Vitamins
Carefully review your medications and health problems with your doctor to ensure it is safe to take this medication. 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. Be sure to discuss this with your doctor.
Do not take this medication for longer than prescribed, as this can increase the risk of developing a second infection. If you become pregnant, plan to become pregnant, or are breastfeeding, notify your doctor immediately. You and your doctor will need to carefully weigh the benefits and risks of taking this medication to ensure the best possible outcome for you and your baby.
Do not take this medication for longer than prescribed, as this can increase the risk of developing a second infection. If you become pregnant, plan to become pregnant, or are breastfeeding, notify your doctor immediately. You and your doctor will need to carefully weigh the benefits and risks of taking this medication to ensure the best possible outcome for you and your baby.
Overdose Information
Overdose Symptoms:
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain
- Electrolyte imbalance (e.g., hyperkalemia due to potassium salt)
- Neuromuscular excitability (e.g., twitching, seizures) in severe cases, especially with renal impairment
What to Do:
Call 1-800-222-1222 (Poison Control Center) immediately or seek emergency medical attention. Treatment is supportive and symptomatic. Hemodialysis may be used in severe cases, especially with renal impairment.
Drug Interactions
Major Interactions
- Methotrexate (increased methotrexate levels and toxicity)
- Tetracyclines (may antagonize the bactericidal effect of penicillin)
Moderate Interactions
- Oral contraceptives (may reduce efficacy of oral contraceptives, though evidence is weak)
- Warfarin (may enhance anticoagulant effect)
- Allopurinol (increased risk of rash with ampicillin, less clear for penicillin V)
- Probenecid (increases and prolongs penicillin levels)
Monitoring
Baseline Monitoring
Allergy history (especially to penicillins or cephalosporins)
Rationale: To prevent severe hypersensitivity reactions
Timing: Prior to first dose
Renal function (CrCl, BUN, creatinine)
Rationale: To guide dose adjustment in patients with impaired renal function
Timing: Prior to initiation in patients with suspected renal impairment
Routine Monitoring
Clinical response to therapy (e.g., fever, symptoms of infection)
Frequency: Daily during acute treatment
Target: Resolution of symptoms
Action Threshold: Lack of improvement or worsening symptoms after 2-3 days; consider alternative diagnosis or antibiotic
Signs of superinfection (e.g., new onset diarrhea, oral thrush, vaginal candidiasis)
Frequency: Throughout therapy and shortly after discontinuation
Target: Absence of new infections
Action Threshold: Presence of new symptoms; investigate and treat appropriately
Symptom Monitoring
- Rash
- Hives
- Itching
- Swelling (face, lips, tongue, throat)
- Difficulty breathing or swallowing (signs of anaphylaxis)
- Severe or watery diarrhea
- Abdominal cramps
- Nausea
- Vomiting
- Oral thrush (white patches in mouth)
- Vaginal itching or discharge
Special Patient Groups
Pregnancy
Penicillin V potassium is generally considered safe for use during pregnancy (Pregnancy Category B). Studies in animals have not shown harm to the fetus, and there is no evidence of harm in well-controlled studies in pregnant women.
Trimester-Specific Risks:
First Trimester:
Low risk, no increased risk of congenital malformations observed.
Second Trimester:
Low risk.
Third Trimester:
Low risk.
Lactation
Penicillin V potassium is considered safe for use during breastfeeding (Lactation Risk L1). It is excreted into breast milk in small amounts, but adverse effects on the infant are unlikely. Monitor for diarrhea, candidiasis, or allergic reactions in the infant.
Infant Risk:
Low risk
Pediatric Use
Widely used and generally safe in pediatric patients. Dosing is weight-based for younger children. Close monitoring for allergic reactions is important.
Geriatric Use
Use with caution in elderly patients, as they are more likely to have decreased renal function. Dose adjustments may be necessary based on creatinine clearance. Monitor for adverse effects and superinfections.
Clinical Information
Clinical Pearls
- Penicillin V potassium is the oral penicillin of choice for most susceptible infections due to its acid stability and good oral absorption.
- It is the first-line treatment for Group A Streptococcal pharyngitis (strep throat) to prevent rheumatic fever.
- Advise patients to complete the full course of antibiotics, even if symptoms improve, to prevent resistance and relapse.
- Instruct patients to report any signs of allergic reaction immediately, especially rash or difficulty breathing.
- While food may decrease the rate of absorption, taking it with food can help reduce gastrointestinal upset, which might improve adherence for some patients.
Alternative Therapies
- Amoxicillin (for broader spectrum or better absorption)
- Cephalexin (a first-generation cephalosporin, often used for similar infections, especially in penicillin-allergic patients who tolerate cephalosporins)
- Azithromycin or Clarithromycin (macrolides, for penicillin-allergic patients)
- Clindamycin (for specific anaerobic infections or in penicillin-allergic patients)
Cost & Coverage
Average Cost:
Varies, typically $10-$30 per 30 tablets
Generic Available:
Yes
Insurance Coverage:
Tier 1 (preferred generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to 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. When seeking help, be prepared to provide details about the medication, including the amount taken and the time it happened, to facilitate prompt and effective treatment.