What Factors Affect a Sufficient Chloroquine Dose?

Chloroquine is a medication that may be used to treat or prevent malaria and certain other parasitic infections. It is part of a larger family of drugs known as quinolines, many of which are potent drugs that can kill parasites. Individuals taking this medication generally use a chloroquine dose that is determined by what condition it is being used to treat. Other factors may influence this dosage as well, including the age and weight of the individual, as well as other medical conditions that are present.

Adults taking this drug to prevent malaria that could be encountered while traveling usually take a chloroquine dose of 500 milligrams (mg) every day before exposure. This dosage must be taken for two weeks in advance of travel. A larger dose may be used if travel will occur in less than two weeks. Known as a loading dose, it is taken a day before travel, and is two doses of 1000 mg taken six hours apart. During travel, and for eight weeks afterward, a dose of 500 mg is taken each day.

Treating malaria that has already developed requires dosing based, in part, on weight. Adults over 60 kilograms (kg) or 132 pounds (lb) should take an immediate chloroquine dose of 1000 mg, with another 500 mg taken at the six hour, 24 hour, and 48 hour mark. For adults under 60 kg, or 132 lb, the initial dose of this drug that should be taken is 16.7 mg per 1 kg, or 2.2 lb, of body weight. At six, 24, and 48 hours, doses of 8.3 mg per 1 kg, or 2.2 lb, of body weight must be taken.

Children may take a chloroquine dose of 8.3 mg per 1 kg, or 2.2 lb, of body weight to prevent malaria, beginning two weeks before travel, and ending eight weeks after. Like adults, a loading dose may be used if the child does not have the two week advance time. In this case, the loading dose is 16.7 mg per 1 kg, or 2.2 lb, of body weight, taken two times, on the day of travel. Then, the 8.3 mg per 1 kg or 2.2 lb dose is taken during and after travel.

Individuals with liver conditions may have difficulties breaking this medication down. Consequently, this drug tends to remain in the body for longer periods of time after dosing. A smaller chloroquine dose should be taken to avoid damaging the liver further, and to avoid having too much of this medication in the body.