What is the drug Paromomycin used for? A guide to its therapeutic applications

October 7, 2025 •

4 min read

First approved for medical use in 1960, the aminoglycoside antibiotic Paromomycin, commonly known by the brand name Humatin, is poorly absorbed by the body, allowing it to act directly within the intestines. This unique property explains what is the drug Paromomycin used for—primarily for treating intestinal parasitic infections and managing hepatic encephalopathy.

Quick Summary

Paromomycin is an aminoglycoside antibiotic used primarily to treat intestinal parasitic infections, such as amebiasis, and as an adjunctive therapy for hepatic encephalopathy (coma). It functions locally within the gastrointestinal tract due to minimal systemic absorption, making it effective for gut-based pathogens.

Key Points

Targeted Treatment: Paromomycin is primarily used for intestinal infections and conditions because of its low absorption into the bloodstream.
Amebiasis Cure: It is prescribed to treat acute and chronic intestinal amebiasis, a parasitic infection of the bowel.
Hepatic Coma Management: As an adjunctive therapy, it helps manage the symptoms of hepatic coma by reducing toxin-producing gut bacteria.
Broad Anti-Parasitic Activity: It is also used to treat other parasitic infections, including cryptosporidiosis, dientamoebiasis, and certain tapeworm infestations.
Mechanism of Action: The drug inhibits protein synthesis in susceptible microorganisms by binding to the ribosomal complex, leading to cell death.
Contraindicated for Bowel Blockage: Paromomycin should not be used in individuals with an intestinal obstruction due to the risk of increased systemic absorption and serious side effects.
Complete the Full Course: It is essential to finish the entire prescription to prevent the infection from returning and becoming drug-resistant.

Primary Uses of Paromomycin

Paromomycin is a versatile antibiotic with several key therapeutic applications, largely focused on conditions within the gastrointestinal tract due to its low systemic absorption. It is available as an oral capsule under the brand name Humatin, among others.

Intestinal Amebiasis

One of the most common uses for paromomycin is treating acute and chronic intestinal amebiasis, a disease caused by the parasite Entamoeba histolytica. This parasite can infect the intestines, leading to symptoms like diarrhea, stomach pain, and cramping. Because paromomycin is not significantly absorbed into the bloodstream, it remains concentrated in the intestines, where it can effectively target and kill the parasite.

Adjunctive Therapy for Hepatic Encephalopathy

Paromomycin is also used as an adjunctive treatment for hepatic encephalopathy, often referred to as hepatic coma. This is a nervous system disorder caused by severe liver disease, where the liver can no longer effectively remove toxins from the blood. In the case of hepatic encephalopathy, bacteria in the gut produce toxins like ammonia. Paromomycin works by suppressing the growth of these intestinal bacteria, thereby reducing the production of toxins and helping to manage the patient's symptoms.

Other Parasitic Infections

Beyond amebiasis, paromomycin has demonstrated efficacy in treating other parasitic infections, particularly those localized to the gut.

Cryptosporidiosis: In immunocompromised patients, particularly those with HIV/AIDS, cryptosporidiosis can cause severe and persistent diarrhea. Paromomycin has been used to manage the symptoms of this infection, although it may not completely eradicate the parasite and is often used in conjunction with other therapies and improved antiretroviral treatment.
Dientamoeba fragilis: Studies have shown paromomycin to be effective, and in some cases superior to metronidazole, in eradicating Dientamoeba fragilis, another intestinal protozoan that can cause gastrointestinal symptoms.
Tapeworm Infections: Paromomycin has also been used to treat various intestinal tapeworm infections, such as those caused by Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm), and Diphyllobothrium latum (fish tapeworm).

How Paromomycin Works: Mechanism of Action

As an aminoglycoside antibiotic, paromomycin's mechanism of action involves inhibiting protein synthesis within susceptible organisms. It achieves this by binding to the 16S ribosomal RNA of the 30S ribosomal subunit in bacteria and parasites. This binding action disrupts the normal process of protein synthesis in several ways:

mRNA Misreading: It causes the misreading of messenger RNA (mRNA), leading to the production of faulty proteins that are non-functional and ultimately lethal to the microorganism.
Ribosomal Inhibition: It stabilizes the ribosomal complex, preventing it from being recycled to produce new proteins.
Membrane Disruption: In some cases, it can also disrupt the membrane potential of the targeted organism.

This mechanism is particularly effective in the gut because the drug remains largely unabsorbed, ensuring high localized concentrations to combat intestinal parasites and bacteria.

Administration

Paromomycin is generally administered orally with meals to minimize gastrointestinal side effects. The specific amount and frequency of administration will depend on the condition being treated and the patient's individual needs. It is crucial to complete the full prescribed course of treatment, even if symptoms improve, to ensure the infection is fully resolved and to minimize the risk of developing drug-resistant organisms.

Potential Side Effects and Contraindications

While paromomycin is generally well-tolerated when used for intestinal infections due to its poor absorption, side effects can occur. Most are mild and gastrointestinal in nature.

Common Side Effects:

Nausea
Stomach cramps
Diarrhea
Loss of appetite

Serious Adverse Effects:

Allergic reactions (rash, hives, itching, swelling of the face, throat)
More serious side effects like kidney damage, ototoxicity (hearing loss), or severe diarrhea can occur if the drug is absorbed systemically, such as in patients with ulcerative lesions of the bowel.
Overgrowth of non-susceptible organisms, including fungi, can result from long-term use.

Contraindications:

Hypersensitivity: Anyone with a known allergy to paromomycin or other aminoglycosides.
Intestinal Obstruction: Patients with a bowel blockage should not take paromomycin due to the increased risk of systemic absorption.
Ulcerative Bowel Lesions: Caution is advised for patients with ulcerative lesions of the bowel, as these conditions can also increase the risk of systemic absorption.

Paromomycin vs. Other Treatments


Feature	Paromomycin	Metronidazole	Tinidazole
Primary Use	Intestinal amebiasis, hepatic coma, other specific parasites	Amebiasis (intestinal and systemic), bacterial vaginosis, trichomoniasis	Amebiasis (intestinal and systemic), trichomoniasis, giardiasis
Systemic Absorption	Poorly absorbed, acts mainly in the intestines	Well absorbed and distributes throughout the body	Well absorbed and distributes throughout the body
Efficacy in D. fragilis	Studies suggest it may be more effective than metronidazole	Variable efficacy, often requiring specific dosing regimens	Effective for giardiasis, also used for amebiasis
Side Effects	Primarily GI-related (nausea, cramps, diarrhea)	More diverse, including headaches, metallic taste, nausea	Similar to metronidazole, including metallic taste
Use for Systemic Infections	Not effective for extraintestinal infections	Can treat systemic infections as it is well absorbed	Can treat systemic infections as it is well absorbed

Conclusion

Paromomycin is an effective and targeted antimicrobial agent with specific and valuable applications in medicine. Its limited systemic absorption is the key to its function, allowing it to effectively treat intestinal parasitic infections like amebiasis, as well as manage the symptoms of hepatic encephalopathy. While its use for systemic infections is limited, it remains an important tool in the treatment of specific gastrointestinal conditions. As with any medication, it should be used under the guidance of a healthcare professional, following the full prescribed amount and duration to ensure optimal results and minimize the risk of complications.

For more in-depth information on drug efficacy and guidelines, consult the Centers for Disease Control and Prevention (CDC)(https://www.cdc.gov/).

Frequently Asked Questions

The most common use for Paromomycin is to treat intestinal amebiasis, a parasitic infection of the bowel, in both acute and chronic forms.

No, Paromomycin is not effective for treating extraintestinal infections because it is poorly absorbed from the gastrointestinal tract into the bloodstream.

For hepatic coma, Paromomycin works by suppressing the growth of intestinal bacteria that produce toxins like ammonia. This helps reduce toxin levels and manage the associated nervous system disorder.

Common side effects typically include nausea, stomach cramps, and diarrhea. These are generally mild and related to the drug's action in the gastrointestinal tract.

Paromomycin capsules should be taken by mouth with food, as directed by your doctor, to minimize gastrointestinal discomfort. Always follow your healthcare provider's specific instructions.

Paromomycin is contraindicated for anyone with an intestinal obstruction or a history of hypersensitivity to aminoglycoside antibiotics. It should be used with caution in individuals with ulcerative bowel lesions.

Paromomycin has shown some activity against cryptosporidiosis, particularly in improving symptoms in immunocompromised patients, but it rarely achieves complete parasite eradication on its own. It is often used alongside other treatments.