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Antiprotozoals: Nursing Pharmacology



atovaquone (Mepron), tinidazole (Tindamax), pyrimethamine (Daraprim), benznidazole (Rochagan, Radanil), nitazoxanide, pentamidine (NebuPent)
Block DNA synthesis in protozoa → prevent reproduction → death
Protozoan infections (e.g., giardiasis, trichomoniasis, intestinal amebiasis)
  • PO (atovaquone, tinidazole, pyrimethamine, benznidazole, nitazoxanide)
  • IV (pentamidine)
  • IM (pentamidine)
  • INH - nebulizer (pentamidine)
  • Headaches, dizziness, peripheral neuropathy, ataxia, loss of coordination
  • Skin rash, urticaria
  • Gastrointestinal disturbances (e.g., unpleasant mouth taste, nausea, vomiting, diarrhea, cramping)
  • Disrupt intestinal flora → bacterial or fungal superinfections
  • Hematologic abnormalities (e.g., leukopenia, anemia, thrombocytopenia)
  • Tinidazole: Boxed warning: malignancy
  • Pregnancy and breastfeeding
  • Children and elderly clients
  • Hematologic disorders
  • Central nervous system disorders
  • Cardiac, hepatic, or renal disease
  • Alcohol use
  • Symptoms of infection; e.g., fatigue, stomach pain and cramping, stool characteristics and frequency, signs of dehydration
  • Laboratory test results: liver function tests, stool culture, DFA

  • Stool culture results
  • Side effects
  • Therapeutic effect of infection resolution
  • Purpose of medication: helps resolve their infection and shorten contagious time
  • Take medication once daily with food
  • Avoid alcohol during treatment and for three days after treatment is complete
  • Common side effects; e.g., headaches, unpleasant taste
  • Notify healthcare provider:
    • Dizziness, peripheral neuropathy
    • Signs of superinfection
  • Resolution of infection takes a few weeks
    • Stool is infectious until they receive a negative stool culture result
    • Precautions to avoid infecting others
      • Wash their hands with soap and water frequently; after using the bathroom; before preparing food or eating
      • Avoid swimming in pools, hot tubs, lakes, rivers, and the ocean until one week after the tinidazole course is complete
  • Prevention of future infections
    • Avoid swallowing water from swimming pools, hot tubs and splash pads
    • Pretreat drinking water when camping or traveling

Antiprotozoals are a group of medications used to treat protozoal infections, such as giardiasis, trichomoniasis, or intestinal amebiasis.

The most commonly used antiprotozoals are atovaquone, tinidazole, benznidazole, pyrimethamine, and nitazoxanide, which can be taken orally; as well as pentamidine that can be administered by nebulizer, intramuscularly, or intravenously.

Once administered, antiprotozoals act on protozoa by blocking DNA synthesis, preventing them from reproducing, and ultimately killing them.

Side effects typically include headaches, dizziness, peripheral neuropathy, ataxia, and loss of coordination. Some clients may also develop a skin rash or urticaria.

In addition, antiprotozoals may often cause gastrointestinal disturbances, such as an unpleasant mouth taste, nausea, vomiting, diarrhea, and cramping.

Moreover, these medications can disrupt the normal intestinal flora, so clients might develop bacterial or fungal superinfections.

Finally, some of these medications can be associated with hematologic abnormalities, such as leukopenia, anemia, or thrombocytopenia; while tinidazole has a boxed warning for increasing the risk of developing malignancy.

Now, antiprotozoals are contraindicated during pregnancy and breastfeeding, while precautions should be taken with children and elderly clients.

In addition, these medications should also be used with caution in clients with hematologic or central nervous system disorders, as well as in those with cardiac, renal, or hepatic disease, and alcoholic beverages should be avoided.

Okay, when caring for a client with giardiasis who has been prescribed tinidazole, first obtain a baseline of your client’s symptoms, such as fatigue, stomach pain and cramping, as well as stool characteristics and frequency.

Then, assess for signs of dehydration, such as decreased urine output, dark yellow urine, or decreased skin turgor.

Lastly, review their most recent laboratory test results, including liver function tests, as well as stool culture and microscopy with direct fluorescent antibody testing, or DFA results.

Now, before your client begins treatment with an antiprotozoal like tinidazole, explain how their medication will help to resolve the infection and shorten the time they’re contagious, and remind them that their symptoms may take a few weeks to resolve.