PLAQUENIL- hydroxychloroquine sulfate tablet
Covis Pharmaceuticals Inc
PHYSICIANS SHOULD COMPLETELY FAMILIARIZE THEMSELVES WITH THE COMPLETE CONTENTS OF THIS LEAFLET BEFORE PRESCRIBING HYDROXYCHLOROQUINE.
Hydroxychloroquine sulfate is a colorless crystalline solid, soluble in water to at least 20 percent; chemically the drug is 2-[[4-[(7-Chloro-4-quinolyl)amino]pentyl]ethylamino] ethanol sulfate (1:1).
PLAQUENIL (hydroxychloroquine sulfate) tablets contain 200 mg hydroxychloroquine sulfate, equivalent to 155 mg base, and are for oral administration.
Inactive Ingredients: Dibasic Calcium Phosphate, Hydroxypropyl Methylcellulose, Magnesium Stearate, Polyethylene glycol 400, Polysorbate 80, Corn Starch, Titanium Dioxide.
The drug possesses antimalarial actions and also exerts a beneficial effect in lupus erythematosus (chronic discoid or systemic) and acute or chronic rheumatoid arthritis. The precise mechanism of action is not known.
PLAQUENIL is indicated for the suppressive treatment and treatment of acute attacks of malaria due to Plasmodium vivax , P. malariae , P. ovale , and susceptible strains of P. falciparum. It is also indicated for the treatment of discoid and systemic lupus erythematosus, and rheumatoid arthritis.
Use of this drug is contraindicated (1) in the presence of retinal or visual field changes attributable to any 4-aminoquinoline compound, (2) in patients with known hypersensitivity to 4-aminoquinoline compounds, and (3) for long-term therapy in children.
PLAQUENIL is not effective against chloroquine-resistant strains of P. falciparum.
Before starting a long-term treatment, both eyes should be carefully examined for visual acuity, central visual field and color vision. Examination should also include fundoscopy. These examinations should be repeated at least annually. Retinal toxicity is largely dose-related.
The risk of retinal damage is small with daily doses of up to 6.5 mg/kg body weight. Exceeding the recommended daily dose sharply increases the risk of retinal toxicity. This examination should be more frequent and adapted to the patient in the following situations:
- daily dosage exceeding 6.5 mg/kg ideal body weight. Absolute body weight used as a guide to dosage, could result in an overdosage in the obese;
- renal insufficiency;
- cumulative dose more than 200 g;
- impaired visual acuity.
If any visual disturbance occurs (visual acuity, color vision), the drug should be immediately discontinued and the patient closely observed for possible progression of the abnormality. Retinal changes (and visual disturbances) may progress even after cessation of the therapy. (See ADVERSE REACTIONS section)
Suicidal behavior has been reported in very rare cases in patients treated with hydroxychloroquine.
Children are especially sensitive to the 4-aminoquinoline compounds. A number of fatalities have been reported following the accidental ingestion of chloroquine, sometimes in relatively small doses (0.75 g or 1 g in one 3-year-old child). Patients should be strongly warned to keep these drugs out of the reach of children.
Use of PLAQUENIL in patients with psoriasis may precipitate a severe attack of psoriasis. When used in patients with porphyria the condition may be exacerbated. The preparation should not be used in these conditions unless in the judgment of the physician the benefit to the patient outweighs the possible hazard.
Usage of this drug during pregnancy should be avoided except in the suppression or treatment of malaria when in the judgment of the physician the benefit outweighs the possible hazard. It should be noted that radioactively-tagged chloroquine administered intravenously to pregnant, pigmented CBA mice passed rapidly across the placenta. It accumulated selectively in the melanin structures of the fetal eyes and was retained in the ocular tissues for five months after the drug had been eliminated from the rest of the body.
Antimalarial compounds should be used with caution in patients with hepatic disease or alcoholism or in conjunction with known hepatotoxic drugs.
Periodic blood cell counts should be made if patients are given prolonged therapy. If any severe blood disorder appears which is not attributable to the disease under treatment, discontinuation of the drug should be considered. The drug should be administered with caution in patients having G-6-PD (glucose-6-phosphate dehydrogenase) deficiency.
Psychiatric disorders: Nervousness, emotional lability, psychosis, suicidal behavior.
Nervous system disorders: Dizziness, headache, convulsions have been reported with this class of drugs.
Eye disorders: Retinopathy with changes in pigmentation and visual field defects have been reported. In its early form, it appears reversible on discontinuation of hydroxychloroquine. If allowed to develop, there may be a risk of progression even after treatment withdrawal. Cases of maculopathies and macular degeneration have been reported and may be irreversible.
Skin and subcutaneous tissue disorders: Bullous eruptions including very rare cases of Erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, photosensitivity and exfoliative dermatitis have been reported.
The 4-aminoquinoline compounds are very rapidly and completely absorbed after ingestion, and in accidental overdosage, or rarely with lower doses in hypersensitive patients, toxic symptoms may occur within 30 minutes. The symptoms of overdosage may include headache, drowsiness, visual disturbances, cardiovascular collapse, convulsions, hypokalemia, rhythm and conduction disorders including QT prolongation, torsade de pointe, ventricular tachycardia and ventricular fibrillation, followed by sudden potentially fatal respiratory and cardiac arrest. Immediate medical attention is required, as these effects may appear shortly after the overdose. Treatment is symptomatic and must be prompt with immediate evacuation of the stomach by emesis (at home, before transportation to the hospital) or gastric lavage until the stomach is completely emptied. If finely powdered, activated charcoal is introduced by the stomach tube, after lavage, and within 30 minutes after ingestion of the tablets, it may inhibit further intestinal absorption of the drug. To be effective, the dose of activated charcoal should be at least five times the estimated dose of hydroxychloroquine ingested. Convulsions, if present, should be controlled before attempting gastric lavage. If due to cerebral stimulation, cautious administration of an ultrashort-acting barbiturate may be tried but, if due to anoxia, it should be corrected by oxygen administration, artificial respiration or, in shock with hypotension, by vasopressor therapy. Because of the importance of supporting respiration, tracheal intubation or tracheostomy, followed by gastric lavage, may also be necessary. Exchange transfusions have been used to reduce the level of 4-aminoquinoline drug in the blood.
A patient who survives the acute phase and is asymptomatic should be closely observed for at least six hours. Fluids may be forced, and sufficient ammonium chloride (8 g daily in divided doses for adults) may be administered for a few days to acidify the urine to help promote urinary excretion in cases of both overdosage and sensitivity.
Like chloroquine phosphate, USP, PLAQUENIL is highly active against the erythrocytic forms of P. vivax and P. malariae and most strains of P. falciparum (but not the gametocytes of P. falciparum).
PLAQUENIL does not prevent relapses in patients with P. vivax or P. malariae malaria because it is not effective against exo-erythrocytic forms of the parasite, nor will it prevent P. vivax or P. malariae infection when administered as a prophylactic. It is highly effective as a suppressive agent in patients with P. vivax or P. malariae malaria, in terminating acute attacks, and significantly lengthening the interval between treatment and relapse. In patients with P. falciparum malaria, it abolishes the acute attack and effects complete cure of the infection, unless due to a resistant strain of P. falciparum.
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