Pentamidine injection is used to treat pneumonia caused by a fungus called Pneumocystis carinii. It is in a class of medications called antiprotozoals. It works by stopping the growth of protozoa that can cause pneumonia.

Pentamidine injection comes as powder to be mixed with liquid to be injected intramuscularly (into a muscle) or intravenously (into a vein) by a doctor or nurse in a medical facility. If it is given intravenously, then it is usually given as a slow infusion over 60 to 120 minutes. The length of treatment depends on the type of infection being treated.

A doctor or nurse will watch you closely while you are receiving the infusion and afterwards to be sure you are not having a serious reaction to the medication. You should be lying down while you receive the medication. Tell your doctor or nurse right away if have any of the following symptoms: dizziness or lightheaded feeling, nausea, blurred vision; cold, clammy, pale skin; or rapid, shallow breathing.

You should begin to feel better during the first 2 to 8 days of treatment with pentamidine. If your symptoms do not improve or get worse, call your doctor.

Before receiving pentamidine injection,

• tell your doctor and pharmacist if you are allergic to pentamidine, any other medications, or any of the ingredients in pentamidine injection. Ask your pharmacist for a list of the ingredients.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: aminoglycoside antibiotics such as amikacin, gentamicin, or tobramycin; amphotericin B (Abelcet, Ambisome), cisplatin, foscarnet (Foscavir), or vancomycin (Vancocin). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have or have ever had high or low blood pressure, abnormal heart rhythms, a low number of red or white blood cells or platelets, a low level of calcium in your blood, Stevens-Johnson syndrome (a severe allergic reaction that may cause the top layer of skin to blister and shed), hypoglycemia (low blood sugar), hyperglycemia (high blood sugar) diabetes, pancreatitis (swelling of the pancreas that does not go away), or liver or kidney disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while receiving pentamidine injection, call your doctor.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

• dizziness, lightheadedness, and fainting
• fast heartbeat, shortness of breath, nausea, or chest pain

Unless your doctor tells you otherwise, continue your normal diet.

Pentamidine injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• loss of appetite
• nausea
• bad taste in the mouth

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• pain, redness, or swelling at the injection site (especially after an intramuscular injection)
• confusion
• hallucinations (seeing things or hearing voices that do not exist)
• rash
• pale skin
• shortness of breath

Pentamidine injection may cause other side effects. Call your doctor if you have any unusual problems while receiving this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Keep all appointments with your doctor and the laboratory. Your doctor may order certain tests before, during, and after your treatment to check your body's response to pentamidine injection. Your doctor will probably monitor your blood pressure and blood glucose levels during and after treatment.

Ask your pharmacist any questions you have about pentamidine injection.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.