How Do Antipneumocystis Agents Work?

Antipneumocystis agents are a class of drugs used to treat a serious lung infection pneumocystis pneumonia (PCP) in people with immune system problems, including those with acquired immunodeficiency syndrome (AIDS) or taking medicines (such as corticosteroids) that lower the body’s ability to fight germs and sickness. PCP is a serious infection caused by the fungus Pneumocystis jirovecii.

The symptoms of PCP can develop over several days or weeks and include:

• Fever
• Cough
• Difficulty breathing
• Chest pain
• Chills
• Fatigue (tiredness)

The only drug that is approved and used as an antipneumocystis agent is “pentamidine”. Pentamidine is an antiprotozoal agent (any agent that kills or inhibits the growth of organisms known as protozoans). It is administered via two routes:

• As an injection that comes as a 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, usually given as a slow infusion over 60 to 120 minutes.
• As a solution to be inhaled using a nebulizer, usually used once every 4 weeks. Inhalation of pentamidine delivers the drug directly to the lungs. 

Antipneumocystis agents work in the following ways:

• They work as antiprotozoals and kill the organism that causes the infection (Pneumocystis jirovecii).
• They inhibit the synthesis of DNA, RNA, phospholipids, and proteins which are essential for the invading organism’s nuclear metabolism.
• This stops the growth and reproduction of the protozoa/fungus and, consequently, causes its death.

Antipneumocystis agents are used in conditions such as:

• Pneumocystis jirovecii pneumonia (an opportunistic infection that occurs in immunosuppressed populations, primarily patients with AIDS infection)
• African Trypanosomiasis (also known as “sleeping sickness” caused by microscopic parasites of the species Trypanosoma brucei)
• Leishmaniasis (infection with Leishmania parasites which causes skin sores and affects several internal organs, usually the spleen, liver, and bone marrow)

Common side effects include:

• Injection site reactions
• Bitter/metallic taste
• Headache
• Diarrhea
• Nausea
• Vomiting
• Loss of appetite
• Dryness of mouth
• Oral Candida (oral thrush)
• Pharyngitis (inflammation of the pharynx, which is in the back of the throat)
• Night sweats
• Upper respiratory tract infection
• Fatigue (tiredness)

Other rare side effects include:

• Dizziness (feeling faint, weak, or unsteady)
• Chest pain
• Abnormal heartbeat
• Shortness of breath or difficulty breathing
• Skin rash
• Confusion
• Slurred speech
• Anemia (results from a lack of red blood cells)
• Hypoglycemia (a condition in which blood sugar (glucose) level is lower than normal)
• Hypotension (low blood pressure)
• Leukopenia (reduced number of white blood cells)
• Increased serum creatinine (creatinine is a waste product that comes from the normal wear and tear of muscles of the body)
• Thrombocytopenia (low blood platelet count)

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Drug names include:

• Nebupent
• Pentam
• Pentamidine