indication

For the treatment of pneumonia due to Pneumocystis carinii.

pharmacology

Pentamidine is an antiprotozoal agent. It is an aromatic diamidine, and is known to have activity against Pneumocystis carinii. The exact nature of its antiprotozoal action is unknown. in vitro studies with mammalian tissues and the protozoan Crithidia oncopelti indicate that the drug interferes with nuclear metabolism producing inhibition of the synthesis of DNA, RNA, phospholipids and proteins. Little is known about the drug's pharmacokinetics. The medication is also useful in Leishmaniasis and in prophylaxis against sleeping sickness caused by Trypanosoma brucei gambiense. Hydration before treatment lessens the incidence and severity of side effects, which include liver or kidney dysfunction, hypertension, hypotension, hypoglycemia, hypocalemia, leukopenia, thrombcytopenia, anemia, and allergic reaction. It is generally well-tolerated.

mechanism of action

The mode of action of pentamidine is not fully understood. It is thought that the drug interferes with nuclear metabolism producing inhibition of the synthesis of DNA, RNA, phospholipids, and proteins.

toxicity

Symptoms of overdose include pain, nausea, anorexia, hypotension, fever, rash, bad taste in mouth, confusion/hallucinations, dizziness, and diarrhea.

biotransformation

Hepatic.

absorption

Absorbed poorly through the gastrointestinal tract and is usually administered parenterally.

half life

9.1-13.2 hours

drug interactions

Artemether: Additive QTc-prolongation may occur. Concomitant therapy should be avoided.

Lumefantrine: Additive QTc-prolongation may occur. Concomitant therapy should be avoided.

Mesoridazine: Increased risk of cardiotoxicity and arrhythmias

Quinupristin: This combination presents an increased risk of toxicity

Tacrolimus: Additive QTc-prolongation may occur increasing the risk of serious ventricular arrhythmias. Concomitant therapy should be used with caution.

Thioridazine: Increased risk of cardiotoxicity and arrhythmias

Thiothixene: May cause additive QTc-prolonging effects. Increased risk of ventricular arrhythmias. Consider alternate therapy. Thorough risk:benefit assessment is required prior to co-administration.

Ticlopidine: Ticlopidine may decrease the metabolism and clearance of Pentamidine. Consider alternate therapy or monitor for adverse/toxic effects of Pentamidine if Ticlopidine is initiated, discontinued or dose changed.

Toremifene: Additive QTc-prolongation may occur, increasing the risk of serious ventricular arrhythmias. Consider alternate therapy. A thorough risk:benefit assessment is required prior to co-administration.

Trimipramine: Additive QTc-prolongation may occur, increasing the risk of serious ventricular arrhythmias. Concomitant therapy should be used with caution.

Voriconazole: Additive QTc prolongation may occur. Consider alternate therapy or monitor for QTc prolongation as this can lead to Torsade de Pointes (TdP).

Vorinostat: Additive QTc prolongation may occur. Consider alternate therapy or monitor for QTc prolongation as this can lead to Torsade de Pointes (TdP).

Zalcitabine: Additive risk of pancreatitis. Concomitant therapy should be avoided.

Ziprasidone: Additive QTc-prolonging effects may increase the risk of severe arrhythmias. Concomitant therapy should be avoided.

Zuclopenthixol: Additive QTc prolongation may occur. Consider alternate therapy or use caution and monitor for QTc prolongation as this can lead to Torsade de Pointes (TdP).