Malaria is common in areas such as Africa, South America, and Southern Asia. This medicine is not effective against all strains of malaria. Plaquenil cause constipation How does chloroquine phosphate work malaria Irreversible retinal damage observed in some patients who had received hydroxychloroquine sulfate; significant risk factors for retinal damage include daily doses of hydroxychloroquine sulfate greater than 6.5 mg/kg 5 mg/kg base of actual body weight, durations of use greater than five years, subnormal glomerular filtration, use of some concomitant drug products such as tamoxifen citrate and concurrent macular disease Initial dose 400 mg 310 mg base orally 1 to 2 times a day; this dose may be continued for several weeks or months, depending on patient response Maintenance dose 200 to 400 mg 155 to 310 mg base orally daily Comments-Each dose should be taken with a meal or a glass of milk. The usual starting dose of Plaquenil is 200 mg twice a day or 400 mg once a day, administered orally, in people weighing 80 kg or more. The usual dosage works for most people who take Plaquenil, but it is possible to increase or decrease the dose based on individual needs. It's important to watch for possible side effects and toxicity. Taking hydroxychloroquine long-term or at high doses may cause irreversible damage to the retina of your eye. Hydroxychloroquine is also an antirheumatic medicine and is used to treat symptoms of rheumatoid arthritis and discoid or systemic lupus erythematosus. Plaquenil first dose Hydroxychloroquine Plaquenil, Hydroxychloroquine Dosage Guide with Precautions - Plaquenil for rheumatoid arthritisOther options for hydroxychloroquine plaquenilPlaquenil visual fieldMacular oct changes in plaquenil toxicity Rheumatoid Arthritis. The action of hydroxychloroquine is cumulative and may require weeks to months to achieve the maximum therapeutic effect see CLINICAL PHARMACOLOGY. Initial adult dosage 400 mg to 600 mg 310 to 465 mg base daily, administered as a single daily dose or in two divided doses. Plaquenil Hydroxychloroquine Uses, Dosage, Side Effects.. Taking Plaquenil for Rheumatoid Arthritis. Plaquenil Uses, Dosage & Side Effects -. Plaquenil comes in 200 mg tablets, and many doctors just off-handedly put everyone on 200 mg twice a day. First dose 1 g chloroquine phosphate 600 mg base orally Second dose 6 hours after first dose 500 mg chloroquine phosphate 300 mg base orally Third dose 24 hours after first dose 500 mg chloroquine phosphate 300 mg base orally Fourth dose 36 hours after first dose 500 mg chloroquine phosphate 300 mg base orally The majority of cases of retinotoxicity have occurred in patients that have had a cumulative dose exceeding 1000g of hydroxychloriquine Plaquenil. This level is reached in about 7 years with the most common daily dose of Plaquenil, 400 mg/day 200 bid.