Antiprotozoal Agents

Causes of Protozoal Infections

• Insect bites
  • Malaria
  • Trypanosomiasis
  • Leishmaniasis
• Ingestion or contact with the causal organism
  • Amebiasis
  • Giardiasis
  • Trichomoniasis

Protozoal Parasites Identified as Causes of Malaria

• Plasmodium falciparum
  • Considered the most dangerous type of protozoan
• Plasmodium vivax
  • Milder form of the disease; seldom results in death
• Plasmodium malariae
  • Endemic in tropical countries; mild symptoms
• Plasmodium ovale
  • Rarely seen; in the process of being eradicated

Life Cycle of Plasmodium

Antimalarials

• Chloroquine (Aralen)
  • Prevention and treatment of plasmodial malaria; treatment of extraintestinal amebiasis
• Halofantrine (Halfan)
  • Treatment of plasmodial malaria in combination with other drugs
• Hydroxychloroquine (Plaquenil)
  • Treatment of plasmodial malaria in combination with other drugs (particularly primaquine)
• Mefloquine (Lariam)
  • Prevention and treatment of plasmodial malaria in combination with other drugs
• Primaquine (generic)
  • Prevention of relapses of Plasmodium vivax and Plasmodium malariae infections
  • Radical cure of P. vivax malaria
• Pyrimethamine (Daraprim)
  • Prevention of plasmodial malaria in combination with other agents to suppress transmission
  • Treatment of toxoplasmosis
• Quinine (generic)
  • Treatment of chloroquine-resistant plasmodial infections

Antimalarials—Action

• Interrupt plasmodial reproduction of protein synthesis
• Agents that do not appear to affect the sporozoites are used for prophylaxis

Antimalarials—Contraindications

• Known allergy
• Liver disease
• Alcoholism
• Lactation
• Cautions
  • Retinal disease or damage
  • Psoriasis

Antimalarials—Adverse Effects

• Headache
• Dizziness
• Fever
• Chills
• Malaise
• Nausea
• Vomiting
• Hepatic dysfunction

Antimalarials—Drug-to-Drug Interactions

• Quinine derivatives and quinine create risk for cardiac toxicity
• Antifolate drugs with pyrimethamine can increase risk of bone marrow suppression

Other Antiprotozoal Drugs

• Actions
  • Inhibit DNA synthesis
• Contraindications
  • Known allergy, pregnancy, CNS disease, and hepatic disease
• Adverse reactions
  • Headache, dizziness, ataxia, nausea, vomiting, and diarrhea

Malaria

• Signs and symptoms
  • Related to the destruction of red blood cells and toxicity to the liver
• Treatment
  • Aims at attacking the parasite at the various stages of its development inside and outside the human body

Other Protozoal Infections

• Amebiasis
• Leishmaniasis
• Trypanosomiasis
• Trichomoniasis
• Giardiasis
• Pneumocystis carinii

Risk Factors for Protozoal Infections

• Unsanitary conditions
• Poor hygienic practices

Prototype Antiprotozoal Agent

Prototype Antifungal Agent

Use of Antifungals Across the Lifespan

Common Antiprotozoal Agents

• Atovaquone (Mepron)
  • Especially active against PCP
• Metronidazole (Flagyl, MetroGel, Noritate)
  • Treats amebiasis, trichomoniasis, and giardiasis
• Pentamidine (Pentam 300, NebuPent)
  • Treats PCP, trypanosomiasis, and leishmaniasis
• Tinidazole (Tindamax)
  • Treats trichomoniasis, giardiasis, and amebiasis

Nursing Considerations for Antimalarial Agents

• Assessment (history and physical exam)
• Nursing diagnosis
• Implementation
• Evaluation

Nursing Considerations for Antiprotozoal Agents

• Assessment (history and physical exam)
• Nursing diagnosis
• Implementation
• Evaluation