Tropical Medicine & Surgery

Patient Management Strategies for Oral Miltefosine in Acanthamoeba Keratitis

Patrick Freitas^* Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, United States of America
^*Correspondence: Patrick Freitas, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, United States of America, Email:

Received: 26-Aug-2024, Manuscript No. TPMS-24-27029; Editor assigned: 28-Aug-2024, Pre QC No. TPMS-24-27029 (PQ); Reviewed: 11-Sep-2024, QC No. TPMS-24-27029; Revised: 18-Sep-2024, Manuscript No. TPMS-24-27029 (R); Published: 26-Sep-2024, DOI: 10.35248/2329-9088.24.12.362

Description

Acanthamoeba Keratitis (AK) is a severe and often sight-threatening infection caused by the free-living amoeba Acanthamoeba. This condition presents a significant therapeutic challenge due to its resistance to standard treatments and the formation of cysts that protect the organism from many antimicrobial agents. Traditional therapies for AK, such as topical antifungal medications and antiseptics, often prove insufficient, particularly in cases where the infection is resistant to these treatments. In such scenarios, alternative therapies must be considered.

Understanding Acanthamoeba Keratitis

Acanthamoeba Keratitis (AK) is an infection of the cornea caused by Acanthamoeba, a free-living amoeba found in soil, water and other natural environments. The disease is characterized by severe pain, redness and vision impairment. Risk factors for AK include contact lens use, particularly when lenses are not properly cleaned or when worn in contaminated water.

The treatment of AK is challenging due to the amoeba's ability to form cysts, which are highly resistant to conventional therapies. Standard treatment regimens often include topical antifungal agents like propamidine isethionate, hexamine and chlorhexidine. Despite these efforts, some cases do not respond adequately, necessitating alternative treatment approaches.

Miltefosine: Miltefosine is an oral phospholipid derivative originally developed as an antileishmanial drug. It has been used effectively in the treatment of leishmaniasis, a parasitic disease caused by protozoan parasites. Recent studies have explored the use of miltefosine for treating other parasitic infections, including Acanthamoeba infections.

Miltefosine has demonstrated broad-spectrum activity against various protozoan and amoebic pathogens. The drug works by disrupting membrane phospholipid biosynthesis, leading to the death of the pathogen. This mechanism of action makes miltefosine a candidate for treating Acanthamoeba keratitis, particularly in cases resistant to standard topical therapies.

Mechanism of action

Miltefosine’s action against Acanthamoeba involves several mechanisms.

Disruption of membrane lipids: Miltefosine integrates into the lipid bilayer of the amoeba's cell membrane, disrupting phospholipid metabolism and leading to cell death.

Inhibition of cyst formation: By affecting the membrane integrity and lipid metabolism, miltefosine may inhibit the formation and maturation of cysts, which are a key factor in the persistence of the infection.

Immune modulation: Miltefosine may also influence host immune responses, enhancing the effectiveness of the body’s own defenses against the pathogen.

Patient management and follow-up

Effective management of patients on oral miltefosine involves comprehensive follow-up care.

Regular assessments: Regular follow-up appointments are necessary to evaluate the clinical response, adjust treatment as needed and monitor for any adverse effects. Corneal imaging and visual acuity tests help assess the progression of the disease and the effectiveness of the therapy.

Patient education: Educating patients about the potential side effects and the importance of adherence to the treatment regimen is vital for ensuring optimal outcomes. Patients should also be informed about the signs of potential complications.

Long-term outcomes: Evaluating long-term outcomes is important to understand the durability of the treatment response and the potential for relapse. Studies on long-term efficacy and safety will contribute to refining treatment protocols and improving patient care.

Administration and dosage

Oral miltefosine is typically administered in tablet form. The dosage regimen can vary depending on the severity of the infection and the patient’s response to treatment.

Dosage regimen: The standard dosage for treating leishmaniasis is 2.5 mg/kg/day for 28 days. For Acanthamoeba keratitis, dosages may be adjusted based on clinical response and tolerance. Some protocols suggest a similar duration but may require adjustments based on patient-specific factors.

Monitoring: Patients on miltefosine therapy should be monitored closely for side effects and efficacy. Regular follow-up visits are essential to assess treatment progress and adjust the regimen as needed.

Safety and side effects

Miltefosine is generally well-tolerated, but it is associated with potential side effects, including.

Gastrointestinal issues: Nausea, vomiting and diarrhea are common side effects that can affect patient compliance.

Hepatotoxicity: Liver function tests should be monitored during treatment, as miltefosine can cause elevations in liver enzymes.

Teratogenicity: Miltefosine is known to be teratogenic and should not be used during pregnancy. Effective contraception is advised for women of childbearing age during treatment.

Other effects: Fatigue, headache and rash have also been reported but are less common.

The application of oral miltefosine for Acanthamoeba keratitis is an area of active research. Future studies should focus on the following aspects.

Optimizing dosage

Determining the most effective dosage and duration of therapy for AK will help maximize efficacy while minimizing side effects.

Combination therapies

Research into combining miltefosine with other antimicrobial agents or adjunctive therapies could enhance treatment outcomes, particularly in cases with severe or resistant infections.

Long-term efficacy

Long-term studies are needed to evaluate the durability of the treatment effect and the potential for recurrence after discontinuation.

Safety profile

Continued assessment of the safety profile, particularly in diverse populations and long-term use, will help establish miltefosine as a reliable option for managing refractory AK.