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penicillin V potassium

Generic Name: penicillin V potassium (oral) (PEN i SIL in V poe TAS ee um)
Brand Name: PC Pen VK

What is penicillin V potassium?

Penicillin V potassium is a slow-onset antibiotic that fights bacteria in your body.

Penicillin V potassium is used to treat many different types of infections including strep and staph infections, pneumonia, rheumatic fever, and infections affecting the mouth or throat.

Penicillin V potassium is also used to prevent infections of the heart valves in people with certain heart conditions who need to have dental work or surgery.

Penicillin V potassium may also be used for purposes not listed in this medication guide.

What is the most important information I should know about penicillin V potassium?

You should not take this medication if you are allergic to penicillin. Tell your doctor if you have ever had an allergic reaction to a cephalosporin antibiotic such as Ceftin, Cefzil, Omnicef, Keflex, and others.

Before taking penicillin V potassium, tell your doctor if you are allergic to cephalosporins such as Ceftin, Cefzil, Keflex, Omnicef, and others, or if you have asthma, kidney disease, a bleeding or blood clotting disorder, a history of diarrhea caused by taking antibiotics, or a history of any type of allergy.

Penicillin V potassium can make birth control pills less effective, which may result in pregnancy. Before taking penicillin V potassium, tell your doctor if you use birth control pills.

Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Penicillin V potassium will not treat a viral infection such as the common cold or flu.

Do not share this medication with another person, even if they have the same symptoms you have.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or has blood in it, call your doctor. Do not use any medicine to stop the diarrhea unless your doctor has told you to.

What should I discuss with my healthcare provider before taking penicillin V potassium?

You should not take this medication if you are allergic to penicillin. Tell your doctor if you have ever had an allergic reaction to a cephalosporin antibiotic such as Ceftin, Cefzil, Omnicef, Keflex, and others.

To make sure you can safely take penicillin V potassium, tell your doctor if you have any of these other conditions:

  • asthma or a history of allergies;

  • kidney disease; or

  • if you are sick with severe vomiting or diarrhea.

FDA pregnancy category B. This medication is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Penicillin V potassium can pass into breast milk and may harm a nursing baby. Do not take this medication without telling your doctor if you are breast-feeding a baby.

How should I take penicillin V potassium?

Take exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.

You may take penicillin V potassium with or without food.

Shake the oral suspension (liquid) well just before you measure a dose. To be sure you get the correct dose, measure the liquid with a marked measuring spoon or medicine cup, not with a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.

Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Penicillin V potassium will not treat a viral infection such as the common cold or flu.

Do not share this medication with another person, even if they have the same symptoms you have.

After you have finished your treatment with penicillin V potassium, your doctor may want to do tests to make sure your infection has completely cleared up.

Store the tablets at room temperature away from moisture, heat, and light.

Store the liquid in a refrigerator. Do not freeze. Throw away any unused liquid after 14 days.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include some of the serious side effects listed in this medication guide.

What should I avoid while taking penicillin V potassium?

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or has blood in it, call your doctor. Do not use any medicine to stop the diarrhea unless your doctor has told you to.

Penicillin V potassium side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

  • diarrhea that is watery or bloody;

  • urinating less than usual or not at all;

  • fever, swollen glands, sore throat, rash or itching, joint pain, general ill feeling;

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

  • pale or yellowed skin, dark colored urine, fever, confusion or weakness; or

  • easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin.

Less serious side effects are more likely to occur, such as:

  • nausea, vomiting, stomach pain;

  • swollen, black, or "hairy" tongue; or

  • vaginal itching or discharge.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

Penicillin V potassium dosing information

Usual Adult Dose for Bacterial Infection:

125 to 500 mg orally every 6 to 8 hours

Comments:
-Therapy should be guided by bacteriological studies (including sensitivity tests) and clinical response.

Use: For the treatment of mild to moderately severe infections due to penicillin G-sensitive microorganisms

Usual Adult Dose for Streptococcal Infection:

125 to 250 mg orally every 6 to 8 hours for 10 days

Comments:
-Streptococci in groups A, C, G, H, L, and M are very sensitive to penicillin; other groups (including group D [enterococcus]) are resistant.

Use: For the treatment of streptococcal infections (without bacteremia) including mild to moderate infections of the upper respiratory tract, scarlet fever, mild erysipelas

Usual Adult Dose for Otitis Media:

Streptococcal infections: 125 to 250 mg orally every 6 to 8 hours for 10 days
Pneumococcal infections: 250 to 500 mg orally every 6 hours until patient afebrile for at least 2 days

Uses:
-Streptococcal infections: For the treatment of mild to moderate infections of the upper respiratory tract
-Pneumococcal infections: For the treatment of mild to moderately severe infections of the respiratory tract, including otitis media

Usual Adult Dose for Upper Respiratory Tract Infection:

Streptococcal infections: 125 to 250 mg orally every 6 to 8 hours for 10 days
Pneumococcal infections: 250 to 500 mg orally every 6 hours until patient afebrile for at least 2 days

Uses:
-Streptococcal infections: For the treatment of mild to moderate infections of the upper respiratory tract
-Pneumococcal infections: For the treatment of mild to moderately severe infections of the respiratory tract, including otitis media

Usual Adult Dose for Skin or Soft Tissue Infection:

250 to 500 mg orally every 6 to 8 hours

Comments:
-Culture and sensitivity studies recommended when treating suspected staphylococcal infections as reports indicate rising numbers of penicillin G-resistant strains.

Use: For the treatment of mild staphylococcal infections (penicillin G-sensitive) of the skin and soft tissues

Infectious Diseases Society of America (IDSA) Recommendations: 250 to 500 mg orally every 6 hours

Comments:
-Recommended for the treatment of streptococcal skin infections
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Fusospirochetosis:

250 to 500 mg orally every 6 to 8 hours

Comments:
-For infections involving gum tissue, completion of essential dental care is recommended.

Use: For the treatment of fusospirochetosis (Vincent's gingivitis and pharyngitis), mild to moderately severe infections of the oropharynx

Usual Adult Dose for Rheumatic Fever Prophylaxis:

125 to 250 mg orally twice a day

Comments:
-Prophylaxis with oral penicillin on a continuing basis has been effective in preventing recurrence.
-Since relatively penicillin-resistant alpha-hemolytic streptococci may be found in patients using continuous therapy for secondary prevention of rheumatic fever, other agents may be selected to add to their continuous prophylactic regimen.

Use: For the prevention of recurrence after rheumatic fever and/or chorea

American Heart Association (AHA) Recommendations: 250 mg orally twice a day

Duration of secondary prophylaxis (after last attack):
-Rheumatic fever with carditis and residual heart disease (persistent valvular disease): 10 years or until 40 years of age (whichever is longer); sometimes lifelong prophylaxis
-Rheumatic fever with carditis and no residual heart disease (no valvular disease): 10 years or until 21 years of age (whichever is longer)
-Rheumatic fever without carditis: 5 years or until 21 years of age (whichever is longer)

Comments:
-Recommended as secondary prevention of rheumatic fever (prevention of recurrence); continuous prophylaxis provides the most effective protection.
-For high-risk patients, penicillin G benzathine given every 3 weeks may be more effective and is recommended; oral therapy can be used for prevention in lower risk patients whose compliance can be ensured.
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Tonsillitis/Pharyngitis:

AHA Recommendations: 500 mg orally 2 to 3 times a day for 10 days

Comments:
-Recommended for the treatment of streptococcal tonsillopharyngitis (primary prevention of rheumatic fever)
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Pharyngitis:

IDSA Recommendations:
-Patients with group A streptococcal pharyngitis: 250 mg orally 4 times a day or 500 mg orally twice a day for 10 days
-Chronic pharyngeal carriers of group A streptococci: 12.5 mg/kg orally 4 times a day for 10 days
---Maximum dose: 2 g/day

Comments:
-Recommended oral regimen for group A streptococcal pharyngitis in patients without penicillin allergy
-With 4 days of oral rifampin, recommended oral regimen for chronic carriers of group A streptococci
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Bacterial Endocarditis Prophylaxis:

2 g orally 1 hour before procedure followed by 1 g orally 6 hours later

Comments:
-The AHA recommends amoxicillin as the oral penicillin regimen for dental procedures; current guidelines should be consulted for additional information.

Use: For prophylaxis against bacterial endocarditis in patients with congenital heart disease or rheumatic or other acquired valvular heart disease for dental procedures or surgical procedures of the upper respiratory tract

Usual Adult Dose for Cutaneous Bacillus anthracis:

US CDC Recommendations: 500 mg orally every 6 hours

Duration of Therapy:
-Bioterrorism-related cases: 60 days
-Naturally acquired cases: 7 to 10 days

Comments:
-Recommended as an alternative oral regimen for the treatment of cutaneous anthrax without systemic involvement; recommended for penicillin-susceptible strains
-Current guidelines should be consulted for additional information.

IDSA Recommendations: 500 mg orally 4 times a day for 7 to 10 days

Comments:
-Recommended regimen for naturally-acquired cutaneous anthrax
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Anthrax Prophylaxis:

US CDC Recommendations: 500 mg orally every 6 hours
Duration of prophylaxis: 60 days

Comments:
-Recommended as an alternative oral regimen for postexposure prophylaxis; recommended for penicillin-susceptible strains
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Joint Infection:

IDSA Recommendations: 500 mg orally 2 to 4 times a day

Comments:
-Recommended as a preferred regimen for chronic oral antibacterial suppression for prosthetic joint infection; recommended for beta-hemolytic streptococci, penicillin-susceptible Enterococcus species, Propionibacterium species
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Bacterial Infection:

12 years or older: 125 to 500 mg orally every 6 to 8 hours

Comments:
-Therapy should be guided by bacteriological studies (including sensitivity tests) and clinical response.

Use: For the treatment of mild to moderately severe infections due to penicillin G-sensitive microorganisms

American Academy of Pediatrics (AAP) Recommendations:
1 month or older: 25 to 75 mg/kg/day orally in 3 or 4 divided doses
Maximum dose: 2 g/day

Comments:
-Recommended for mild to moderate infections; this drug is inappropriate for severe infections.
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Streptococcal Infection:

12 years or older: 125 to 250 mg orally every 6 to 8 hours for 10 days

Comments:
-Streptococci in groups A, C, G, H, L, and M are very sensitive to penicillin; other groups (including group D [enterococcus]) are resistant.

Uses: For the treatment of streptococcal infections (without bacteremia) including mild to moderate infections of the upper respiratory tract, scarlet fever, mild erysipelas

Usual Pediatric Dose for Otitis Media:

12 years or older:
-Streptococcal infections: 125 to 250 mg orally every 6 to 8 hours for 10 days
-Pneumococcal infections: 250 to 500 mg orally every 6 hours until patient afebrile for at least 2 days

Uses:
-Streptococcal infections: For the treatment of mild to moderate infections of the upper respiratory tract
-Pneumococcal infections: For the treatment of mild to moderately severe infections of the respiratory tract, including otitis media

Usual Pediatric Dose for Upper Respiratory Tract Infection:

12 years or older:
-Streptococcal infections: 125 to 250 mg orally every 6 to 8 hours for 10 days
-Pneumococcal infections: 250 to 500 mg orally every 6 hours until patient afebrile for at least 2 days

Uses:
-Streptococcal infections: For the treatment of mild to moderate infections of the upper respiratory tract
-Pneumococcal infections: For the treatment of mild to moderately severe infections of the respiratory tract, including otitis media

Usual Pediatric Dose for Skin or Soft Tissue Infection:

12 years or older: 250 to 500 mg orally every 6 to 8 hours

Comments:
-Culture and sensitivity studies recommended when treating suspected staphylococcal infections as reports indicate rising numbers of penicillin G-resistant strains.

Use: For the treatment of mild staphylococcal infections (penicillin G-sensitive) of the skin and soft tissues

Usual Pediatric Dose for Fusospirochetosis:

12 years or older: 250 to 500 mg orally every 6 to 8 hours

Comments:
-For infections involving gum tissue, completion of essential dental care is recommended.

Use: For the treatment of fusospirochetosis (Vincent's gingivitis and pharyngitis), mild to moderately severe infections of the oropharynx

Usual Pediatric Dose for Rheumatic Fever Prophylaxis:

12 years or older: 125 to 250 mg orally twice a day

Comments:
-Prophylaxis with oral penicillin on a continuing basis has been effective in preventing recurrence.
-Since relatively penicillin-resistant alpha-hemolytic streptococci may be found in patients using continuous therapy for secondary prevention of rheumatic fever, other agents may be selected to add to their continuous prophylactic regimen.

Use: For the prevention of recurrence after rheumatic fever and/or chorea

AHA and AAP Recommendations for Children: 250 mg orally twice a day

Duration of secondary prophylaxis (after last attack):
-Rheumatic fever with carditis and residual heart disease (persistent valvular disease): 10 years or until 40 years of age (whichever is longer); sometimes lifelong prophylaxis
-Rheumatic fever with carditis and no residual heart disease (no valvular disease): 10 years or until 21 years of age (whichever is longer)
-Rheumatic fever without carditis: 5 years or until 21 years of age (whichever is longer)

Comments:
-Recommended as secondary prevention of rheumatic fever (prevention of recurrence); continuous prophylaxis provides the most effective protection.
-For high-risk patients, penicillin G benzathine every 3 weeks may be more effective and is recommended; oral therapy can be used for prevention in lower risk patients whose compliance can be ensured.
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Tonsillitis/Pharyngitis:

AHA Recommendations:
-Children 27 kg or less: 250 mg orally 2 to 3 times a day
-Children greater than 27 kg and adolescents: 500 mg orally 2 to 3 times a day
Duration of therapy: 10 days

Comments:
-Recommended for the treatment of streptococcal tonsillopharyngitis (primary prevention of rheumatic fever)
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Pharyngitis:

IDSA Recommendations:
Patients with group A streptococcal pharyngitis:
-Children: 250 mg orally 2 to 3 times a day
-Adolescents: 250 mg orally 4 times a day or 500 mg orally twice a day
Duration of therapy: 10 days

Chronic pharyngeal carriers of group A streptococci: 12.5 mg/kg orally 4 times a day for 10 days
-Maximum dose: 2 g/day

Comments:
-Recommended oral regimen for group A streptococcal pharyngitis in patients without penicillin allergy
-With 4 days of oral rifampin, recommended oral regimen for chronic carriers of group A streptococci
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Pneumonia:

Pediatric Infectious Diseases Society and IDSA Recommendations:
3 months or older: 50 to 75 mg/kg/day orally in 3 or 4 divided doses

Comments:
-Recommended as a preferred oral regimen for community-acquired pneumonia due to group A streptococci; recommended for step-down therapy or mild infection
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Bacterial Endocarditis Prophylaxis:

12 years or older:
-Less than 27 kg: 1 g orally 1 hour before procedure followed by 500 mg orally 6 hours later
-At least 27 kg: 2 g orally 1 hour before procedure followed by 1 g orally 6 hours later

Comments:
-The AHA recommends amoxicillin as the oral penicillin regimen for dental procedures; current guidelines should be consulted for additional information.

Use: For prophylaxis against bacterial endocarditis in patients with congenital heart disease or rheumatic or other acquired valvular heart disease for dental procedures or surgical procedures of the upper respiratory tract

Usual Pediatric Dose for Inhalation Bacillus anthracis:

AAP Recommendations:
Up to 1 week of age:
-Gestational age 32 to 37 weeks: 25 mg/kg orally every 12 hours
-Term neonate: 25 mg/kg orally every 8 hours

1 to 4 weeks:
-Gestational age 32 to 37 weeks: 25 mg/kg orally every 8 hours
-Term neonate: 75 mg/kg/day orally in divided doses every 6 to 8 hours

1 month or older: 50 to 75 mg/kg/day orally in divided doses every 6 to 8 hours

Duration of Therapy:
Postexposure prophylaxis for B anthracis infection: 60 days after exposure

Cutaneous anthrax without systemic involvement:
-Bioterrorism-related cases: To complete an antimicrobial regimen of up to 60 days from onset of illness
-Naturally-acquired cases: 7 to 10 days

Follow-up for severe anthrax:
-To complete a regimen of 10 to 14 days or longer (up to 4 weeks of age) or to complete a regimen of 14 days or longer (1 month or older)
-Patients may require prophylaxis to complete an antimicrobial regimen of up to 60 days from onset of illness.

Comments:
-Recommended as an alternative regimen for postexposure prophylaxis, the treatment of cutaneous anthrax without systemic involvement, and oral follow-up therapy for severe anthrax
-Recommended as an alternative for penicillin-susceptible strains
-Recommended for use with a protein synthesis inhibitor when used for follow-up therapy for severe anthrax (includes anthrax meningitis, inhalation anthrax, injection anthrax, gastrointestinal anthrax, and cutaneous anthrax with systemic involvement, extensive edema, or lesions of the head or neck).
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Cutaneous Bacillus anthracis:

AAP Recommendations:
Up to 1 week of age:
-Gestational age 32 to 37 weeks: 25 mg/kg orally every 12 hours
-Term neonate: 25 mg/kg orally every 8 hours

1 to 4 weeks:
-Gestational age 32 to 37 weeks: 25 mg/kg orally every 8 hours
-Term neonate: 75 mg/kg/day orally in divided doses every 6 to 8 hours

1 month or older: 50 to 75 mg/kg/day orally in divided doses every 6 to 8 hours

Duration of Therapy:
Postexposure prophylaxis for B anthracis infection: 60 days after exposure

Cutaneous anthrax without systemic involvement:
-Bioterrorism-related cases: To complete an antimicrobial regimen of up to 60 days from onset of illness
-Naturally-acquired cases: 7 to 10 days

Follow-up for severe anthrax:
-To complete a regimen of 10 to 14 days or longer (up to 4 weeks of age) or to complete a regimen of 14 days or longer (1 month or older)
-Patients may require prophylaxis to complete an antimicrobial regimen of up to 60 days from onset of illness.

Comments:
-Recommended as an alternative regimen for postexposure prophylaxis, the treatment of cutaneous anthrax without systemic involvement, and oral follow-up therapy for severe anthrax
-Recommended as an alternative for penicillin-susceptible strains
-Recommended for use with a protein synthesis inhibitor when used for follow-up therapy for severe anthrax (includes anthrax meningitis, inhalation anthrax, injection anthrax, gastrointestinal anthrax, and cutaneous anthrax with systemic involvement, extensive edema, or lesions of the head or neck).
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Anthrax Prophylaxis:

AAP Recommendations:
Up to 1 week of age:
-Gestational age 32 to 37 weeks: 25 mg/kg orally every 12 hours
-Term neonate: 25 mg/kg orally every 8 hours

1 to 4 weeks:
-Gestational age 32 to 37 weeks: 25 mg/kg orally every 8 hours
-Term neonate: 75 mg/kg/day orally in divided doses every 6 to 8 hours

1 month or older: 50 to 75 mg/kg/day orally in divided doses every 6 to 8 hours

Duration of Therapy:
Postexposure prophylaxis for B anthracis infection: 60 days after exposure

Cutaneous anthrax without systemic involvement:
-Bioterrorism-related cases: To complete an antimicrobial regimen of up to 60 days from onset of illness
-Naturally-acquired cases: 7 to 10 days

Follow-up for severe anthrax:
-To complete a regimen of 10 to 14 days or longer (up to 4 weeks of age) or to complete a regimen of 14 days or longer (1 month or older)
-Patients may require prophylaxis to complete an antimicrobial regimen of up to 60 days from onset of illness.

Comments:
-Recommended as an alternative regimen for postexposure prophylaxis, the treatment of cutaneous anthrax without systemic involvement, and oral follow-up therapy for severe anthrax
-Recommended as an alternative for penicillin-susceptible strains
-Recommended for use with a protein synthesis inhibitor when used for follow-up therapy for severe anthrax (includes anthrax meningitis, inhalation anthrax, injection anthrax, gastrointestinal anthrax, and cutaneous anthrax with systemic involvement, extensive edema, or lesions of the head or neck).
-Current guidelines should be consulted for additional information.

What other drugs will affect penicillin V potassium?

Tell your doctor about all other medicines you use, especially:

  • birth control pills;

  • methotrexate (Rheumatrex, Trexall);

  • probenecid (Benemid); or

  • a tetracycline antibiotic, such as doxycycline (Doryx, Oracea, Periostat, Vibramycin), minocycline (Dynacin, Minocin, Solodyn, Vectrin), or tetracycline (Brodspec, Panmycin, Sumycin, Tetracap).

This list is not complete and other drugs may interact with penicillin V potassium. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

Where can I get more information?

  • Your pharmacist can provide more information about penicillin V potassium.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2012 Cerner Multum, Inc. Version: 1.01.

Date modified: May 03, 2017
Last reviewed: February 07, 2011

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