Penicillin VK Side Effects Center

What Is Penicillin VK?

Penicillin V potassium (penicillin VK) is an antibiotic used to treat mild to moderately severe infections due to penicillin G-sensitive microorganisms. Penicillin VK is available in generic form.

What Are Side Effects of Penicillin VK?

Side effects of penicillin VK include:

• nausea,
• vomiting,
• diarrhea,
• abdominal pain,
• stomach upset,
• skin rash,
• hives,
• itching, and
• black "hairy" tongue.

Patients with a history of allergic reactions to other penicillins should not receive penicillin VK. Serious but rare reactions to penicillin VK include:

• seizures,
• severe allergic reactions (anaphylaxis), and
• low platelet or red blood cell count.

Penicillin VK can alter the normal bacteria in the colon and allow overgrowth of some bacteria such as Clostridium difficile, which causes inflammation of the colon (pseudomembranous colitis).

Penicillin VK may cause serious side effects including:

• skin rash, no matter how small,
• red or scaly skin,
• fever,
• chills,
• swollen glands,
• muscle or joint pain,
• fast heartbeats,
• general ill feeling,
• lightheadedness,
• severe stomach pain,
• diarrhea that is watery or bloody,
• little or no urinating,
• bruising,
• severe tingling,
• numbness,
• pain,
• muscle weakness,
• seizure (convulsions), and
• unusual changes in mood or behavior

Get medical help right away, if you have any of the symptoms listed above.

Seek medical care or call 911 at once if you have the following serious side effects:

• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheartedness, or passing out;
• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

Dosage for Penicillin VK

The usual adult dose of penicillin VK is 125 to 500 mg every 6-8 hours.

What Drugs, Substances, or Supplements Interact with Penicillin VK?

Benemid (Probenecid) causes an increase in the level of penicillin VK in the blood by reducing the elimination of penicillin by the kidneys.

Penicillin VK During Pregnancy and Breastfeeding

Penicillin VK is considered safe during pregnancy. Penicillin VK is excreted in breast milk and may cause diarrhea or allergic responses in nursing infants.

Additional Information

Our Penicillin VK Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

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.

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:

• the first sign of any skin rash, no matter how mild;
• red or scaly skin;
• fever, chills, swollen glands, muscle or joint pain, fast heartbeats, general ill feeling;
• a light-headed feeling, like you might pass out;
• severe stomach pain, diarrhea that is watery or bloody;
• little or no urinating;
• bruising, severe tingling, numbness, pain, muscle weakness;
• seizure (convulsions); or
• unusual changes in mood or behavior.

Common side effects may include:

• mild diarrhea;
• headache;
• black or hairy tongue; or
• pain, swelling, bruising, or irritation around the IV needle.

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.