Which medications in the drug class Antiprotozoal Agents are used in the treatment of Leishmaniasis?

Updated: Feb 18, 2020
  • Author: Craig G Stark, MD, FACP, FFTM, RCPS(Glasg), FISTM; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Answer

Antiprotozoal Agents

Antiprotozoan compounds are the drugs of choice in patients with visceral leishmaniasis. Parasite biochemical pathways are sufficiently different from the human host to allow selective interference by chemotherapeutic agents in relatively small doses.

Protozoal infections are typically more severe in immunocompromised patients than in immunocompetent patients. These infections occur throughout the world and are a major cause of morbidity and mortality in some regions. Primary immune deficiency is rare, whereas secondary deficiency is more common.

Immunosuppressive therapy, cancer and its treatment, infection with human immunodeficiency virus (HIV), and splenectomy all may increase vulnerability to infection. The infectious risk is proportional to neutropenia duration and severity.

Pentamidine (Pentam)

Pentamidine is a first-line medication in cutaneous leishmaniasis except for L mexicana (ketoconazole 600 mg PO qd for 28 d). It is a treatment alternative in visceral leishmaniasis.

This agent inhibits growth of protozoa by (1) interacting with trypanosomal kinetoplast DNA, (2) interfering with polyamine synthesis by a decrease in the activity of ornithine decarboxylase, and (3) and inhibiting incorporation of nucleic acids into RNA and DNA, causing inhibition of protein and phospholipid synthesis.

Pentamidine is well absorbed and highly tissue bound. This medication is formulated as a sterile powder and must be reconstituted and administered as slow IV infusion or via the IM route. Because patients receiving daily injections do not reach a steady-state plasma concentration and elimination half-life is 12 days, a great deal of accumulation of pentamidine can occur in tissues such as the liver, kidney, and spleen.

Resistance to pentamidine is common in India, with high relapse rates reported.

Paromomycin

Paromomycin is an oral orphan drug consisting of an amebicidal and antibacterial aminoglycoside obtained from a strain of Streptomyces rimosus that is active in intestinal amebiasis.

Paromomycin has a relatively favorable adverse effect profile, but it is not as effective as antimony or amphotericin B for visceral disease when used as monotherapy. Paromomycin can be used in combination with sodium antimony gluconate to reduce the total time of therapy, and it has better cure rates.

Intravenous and topical paromomycin products are not available in the United States.


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