Antiprotozoal Agents Cheat Sheet

 

MALARIA

Malaria is a parasitic disease that has killed hundreds of millions of people and even changed the course of history. The progress of several African battles and the building of the Panama Canal were altered by outbreaks of malaria.

              Antiprotozoal Agents
Anti-Malarials
Other Anti-Protozoal  
  • Chloroquine
  • Hydroxychloroquine
  • Mefloquine 
  • Primaquine 
  • Pyrimethamine
  • Atovaquone
  • Metronidazole 
  • Nitazoxanide
  • Pentamidine 
  • Tinidazole

Even with the introduction of drugs for the treatment of this disease, it remains endemic in many parts of the world. The only known method of transmission of malaria is through the bite of a female Anopheles mosquito, an insect that harbors the protozoal parasite and carries it to humans. Four protozoal parasites, all in the genus Plasmodium, have been identified as causes of malaria:

Antimalarials Dosage Guideline
Drug Name
Dosage/Route
Usual Indications
Chloroquine
(Aralen)
Suppression: Adult: 300 mg
PO every week beginning
1–2 wk before exposure and continuing for 4 wk after leaving endemic
area
Pediatric: 5 mg/kg/wk PO,
using same schedule as for an adult
Acute attacks:
Adult: 600 mg PO, followed
by 300 mg PO in 6 h; then 300 mg PO on days 2 and 3
Pediatric: 10 mg/kg PO,
followed by 5 mg/kg PO in 6 h and on days 2 and 3
Prevention and treatment of Plasmodium malaria; treatment of
extraintestinal amebiasis
Hydroxychloroquine
Suppression: Adult: 310 mg
PO every week, beginning 1–2 wk before exposure and continuing for 4 wk after
leaving endemic area
Pediatric: 5 mg/kg/wk,
following adult
schedule
Acute attack:
Adult: 620 mg PO, followed
by 310 mg PO in 6 h and on days 2 and 3 Pediatric:
10 mg
/kg PO, followed by 5 mg/kg PO in 6 h and on days 2 and 3
Treatment of Plasmodium malaria in combination with other drugs,
particularly primaquine
Mefloquine
(Lariam)
Treatment: Adult: 1250 mg PO as a single dose Prevention:
Adult: 250 mg PO once weekly, starting 1 wk before travel and
continuing for 4 wk after leaving endemic area Pediatric: 15–19 kg,1/4
tablet; 20–30 kg, 1/2 tablet; 31–45 kg, 3/4 tablet; [1]45 kg, 1 tablet;
once a week, starting 1 wk before travel and continuing until 4 wk after
leaving area
Prevention and treatment of Plasmodium malaria in
combination with other drugs
Primaquine
(generic)
Adult: 26.3 mg/d PO for 14 d Pediatric: 0.5 mg/kg per day PO for 14
d; begin therapy during last 2 wk of (or after)
therapy with chloroquine or other drugs
Prevention of relapses of P. vivax and P. malariae infections;
radical cure of P. vivax malaria
Pyrimethamine (Daraprim)
Prevention: Adult: 25 mg PO every week Pediatric ([1]10 yr): same as
adult Pediatric (4–10 yr): 12.5 mg PO every week
Pediatric (

4 yr): 6.25 mg PO every week

Toxoplasmosis:
Adult: 50–75 mg/d PO with 1–4 g of a sulfonamide, for 4–5 wk
Pediatric: 1 mg/kg/d PO, divided into two equal doses, for 2–4 d;
then cut dose in half and continue for 1 mo
Prevention of Plasmodium malaria, in combination with other agents to
suppress transmission; treatment of other agents to suppress transmission;
treatment of

ANTIMALARIALS

Antimalarial drugs (Table 12.1) are usually given in combination form to attack the Plasmodium at various stages of its life cycle. Using this approach, it is possible to prevent the acute malarial reaction in individuals who have been infected by the parasite.

 

These drugs can be schizonticidal (acting against the red-blood-cell phase of the life cycle), gametocytocidal (acting against the gametocytes), sporontocidal (acting against the parasites that are developing in the mosquito), or work against tissue schizonts as prophylactic or antirelapse agents.

 

Quinine (generic) was the first drug found to be effective in the treatment of malaria; it is no longer available. Antimalarials used today include chloroquine (Aralen), hydroxychloroquine (Plaquenil), mefloquine (Lariam), primaquine (generic), and pyrimethamine (Daraprim). Fixeddose combination drugs for malaria prevention and treatment are discussed in Box 12.2.

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