For the treatment of malaria:
Adults and children: 25 mg of the drug per kg of body weight, taken over 3 days.
For example, 10 mg per kg on the first day, followed by 5 mg per kg after 6 to 8 hours, and then 5 mg per kg each day for the next 2 days. Alternatively, adults can take 600 mg initially, followed by 300 mg after 6 to 8 hours, and 300 mg daily for the next 2 days.

For preventing malaria:
Adults: A dose of 300 mg (chloroquine base) every week, starting at least one week before exposure, and continuing for 4 weeks after exposure.
Children: 5 mg per kg of body weight every week.

For amoebic hepatitis:
Adults: 600 mg daily for 2 days, then 300 mg daily for 2-3 weeks, often with another treatment for intestinal amoebiasis.

For lupus:
Suggested dose is 150 mg daily, reducing when symptoms are under control.

For rheumatoid arthritis:
Adults: 150 mg daily, with treatment given for only 10 months each year.
Children: 3 mg per kg body weight daily.

For photoallergic reactions:
Adults: 150 to 300 mg daily during periods of intense light exposure.
Children: 3 mg per kg body weight.

For porphyria cutanea tarda:
Use 75 mg 2-3 times a week for 6-18 months to avoid toxic effects.