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Pentam 300

Generic name: pentamidinepen-TAM-e-deen ]
Brand names: Nebupent, Pentam 300
Drug classes: Inhaled anti-infectives, Miscellaneous antibiotics

Medically reviewed by on Oct 4, 2022. Written by Cerner Multum.

What is Pentam 300?

Pentam 300 is an antifungal medication that fights infections caused by fungus.

Pentam 300 is used to prevent and treat pneumonia caused by Pneumocystis jiroveci (carinii).

Pentam 300 may also be used for purposes not listed in this medication guide.


Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

You should not use Pentam 300 if you are allergic to it.

To make sure Pentam 300 is safe for you, tell your doctor if you have:

FDA pregnancy category C. It is not known whether Pentam 300 will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.

It is not known whether pentamidine passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using Pentam 300.

Inhaled Pentam 300 should not be given to a child without the advice of a doctor.

How is Pentam 300 given?

Pentam 300 is given either as an injection, or as in inhaled medicine using a nebulizer. Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Pentam 300 is a powder medicine that must be mixed with a liquid (diluent) before using it as an injection or with a nebulizer. If you are using this medicine at home, be sure you understand how to properly mix and store the medicine. Use only the diluent provided with your medication.

To use Pentam 300 as an injection:

  • Pentam 300 is injected into a muscle, or into a vein through an IV. You may be shown how to use an IV at home. Do not self-inject this medicine if you do not understand how to give the injection and properly dispose of used needles, IV tubing, and other items used to inject the medicine.

  • Do not use Pentam 300 if it has changed colors or has particles in it. Call your pharmacist for new medication.

  • Tell your caregivers if you feel any burning, pain, or swelling around the IV needle when Pentam 300 is injected.

  • Use a disposable needle only once, then throw away in a puncture-proof container (ask your pharmacist where you can get one and how to dispose of it). Keep this container out of the reach of children and pets.

To use Pentam 300 with a nebulizer:

  • After mixing your medicine with the diluent, pour all of the mixture into the chamber of the nebulizer. Attach the mouthpiece or face mask, then attach the drug chamber to the compressor.

  • Do not mix any other medicines in the nebulizer with Pentam 300.

  • Sit upright in a comfortable position. Place the mouthpiece into your mouth or put on the face mask, covering your nose and mouth. Turn on the compressor.

  • Breathe in slowly and evenly until no more mist is formed by the nebulizer and the drug chamber is empty.

  • Clean the nebulizer after each use. Follow the cleaning directions that came with your nebulizer.

If you are diabetic, check your blood sugar carefully while you are receiving Pentam 300. This medicine can raise or lower your blood sugar.

While using Pentam 300, you may need frequent blood tests. Your heart function may need to be checked using an electrocardiograph or ECG (sometimes called an EKG).

Store unmixed medicine at room temperature away from moisture, heat, and light.

Mixed medicine must be used within a certain number of hours, depending on the diluent. Carefully follow the mixing and storage instructions provided with your medicine. Ask your pharmacist if you have questions.

Pentam 300 contains no preservative. Throw away any unused medicine.

What happens if I miss a dose?

Call your doctor for instructions if you miss a dose of Pentam 300.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using Pentam 300?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Pentam 300 side effects

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

Pentam 300 may cause serious side effects. Call your doctor at once if you have:

  • wheezing, choking, or other breathing problems after using this medication with a nebulizer;

  • a light-headed feeling, like you might pass out;

  • fast or uneven heart rate;

  • painful or difficult urination;

  • confusion, hallucinations;

  • pain, burning, irritation, or skin changes where the injection was given;

  • worsening symptoms, or signs of a new infection (fever, cough, trouble breathing, night sweats);

  • a blood cell disorder--pale skin, feeling light-headed or short of breath, easy bruising, unusual bleeding, purple or red pinpoint spots under your skin;

  • pancreatitis--severe pain in your upper stomach spreading to your back, nausea and vomiting;

  • low blood sugar--headache, hunger, weakness, sweating, confusion, irritability, dizziness, or feeling jittery; or

  • severe skin reaction--fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Common side effects of Pentam 300 may include:

  • loss of appetite; or

  • unusual or unpleasant taste in the mouth.

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.

What other drugs will affect Pentam 300?

Other drugs may interact with pentamidine, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Further information

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.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.