Paromomycin
Other antiprotozoals
Other antiprotozoals
Aminoglycoside that is barely absorbed by mouth: it clears amoebae from the bowel lumen. An injectable form treats visceral leishmaniasis.
Also called: paromomycin sulfate, aminosidine
Quick facts
- Group
- Other antiprotozoals
- Target
- Decoding (A) site of the 16S ribosomal RNA, small ribosomal subunit
- Used for
- Intestinal amoebiasis · Asymptomatic carriers
- Key effects
- Nausea
- Monitor
- Kidney function in people · New infections
- ATC
- A07AA06
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows paromomycin bound to a short RNA that reproduces the bacterial A site, not a whole ribosome; it acts on the same site of the parasite's ribosome.
Paromomycin is an aminoglycoside. It binds the decoding site of the small ribosomal subunit, makes the ribosome misread the messenger RNA and so stops normal protein synthesis in amoebae and bacteria. Taken by mouth it stays almost entirely in the gut, which is why it acts on parasites living in the bowel lumen and not on amoebae that have invaded tissue.
- Binds the decoding (A) site of the small ribosomal subunit
- The ribosome misreads the messenger RNA
- Faulty proteins form and the organism dies
- By mouth it stays in the gut lumen, where the cysts live
Indications
- Intestinal amoebiasis, acute and chronic, as the luminal agent; after metronidazole or tinidazole for invasive disease Intestinal amoebiasis (amoebic dysentery) →
- Asymptomatic carriers of Entamoeba histolytica cysts Intestinal amoebiasis (amoebic dysentery) →
- Adjunct in hepatic coma, to reduce ammonia-producing gut bacteria
- Visceral leishmaniasis (injectable form on the WHO list) Leishmaniasis →
Adverse effects
Common
- Nausea, abdominal cramps and diarrhoea, mostly at high doses
Contraindications
- Allergy to paromomycin
- Intestinal obstruction
Key interactions
- Metronidazole or tinidazole
- Complementary, not simultaneous: the nitroimidazole kills tissue amoebae, then paromomycin clears the lumen.
- Other kidney- or ear-toxic drugs (other aminoglycosides, injectable form)
- Added toxicity is possible when the drug reaches the blood; kidney function is watched.
What is monitored
- Stool tests after treatment to confirm the cysts are gone
- Kidney function in people with ulcerated bowel or with the injectable form
- New infections or overgrowth during treatment
Administration and safety
- Oral capsules for intestinal amoebiasis; the injectable form is a separate product used for visceral leishmaniasis
- Given after the nitroimidazole course, not at the same time, so diarrhoea from either can be told apart
Pregnancy and breastfeeding
Because so little is absorbed, it is an option for luminal infections in pregnancy when treatment cannot wait.
Nursing care
- Ask about bowel obstruction and kidney disease
- Explain that a stool test is repeated after treatment
- Teach hand washing and safe water and food to prevent reinfection and spread
- Report severe diarrhoea or reduced urine output
Pharmacokinetics
- Absorption
- Very poorly absorbed by mouth; almost all of an oral dose is recovered in the stool.
- Elimination
- Oral: in the faeces. Absorption can rise through ulcerated bowel, with a risk of kidney toxicity.
Test yourself
Think of the answer, then tap the question to see it.
Why does oral paromomycin act only on amoebae in the bowel lumen?
It is barely absorbed, so it stays in the gut and does not reach amoebae in the bowel wall or liver.
In amoebic colitis or liver abscess, when is paromomycin given?
After metronidazole or tinidazole, to eradicate the cysts that remain in the bowel lumen.
Why is paromomycin used with caution when the bowel is ulcerated?
More drug can be absorbed through the damaged bowel and cause kidney toxicity, as other aminoglycosides do.
What is the injectable form of paromomycin used for?
Visceral leishmaniasis; it is on the WHO Essential Medicines List for that use.
Connections
← Back to the class: Other antiprotozoals
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - PAROMOMYCIN SULFATE capsule (DailyMed (U.S. National Library of Medicine), 2026); eEML - Electronic Essential Medicines List (World Health Organization (WHO), 2026); Complex between Paromomycin and the 16S-rRNA A-site at 2.5 A resolution (RCSB Protein Data Bank, 2026).
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Representative model, for educational purposes only.