Digoxin

Concurrent administration of hydroxychloroquine and digoxin has been reported to increase serum digoxin levels. Monitor digoxin levels. Hydroxychloroquine sulphate may also be subject to several known interations of cholroquine even though reports have not been recorded.

These include- - potentation of its direct blocking at the neuromuscular nunction by aminoglucosides antibiotcs - inhibition of of its metabolism by cimetidine which may increase plasma conc. of antimalarial - antagonism effect of neostigmine & pyridostigmine , - reduction of antibody response to primary immunisation with intradermal human-diplod cell rabies vaccine Antacids may reduce absorption of hydroxychloroquine so it is advised that a 4 hour interval be observed between hydrxychloroquine and antacid dosing Concurrent use of penicillamine with hydroxychloroquine may increase penicilamine plasma conc. increasing the potential for serious hematological and or renal adverse reactions as well as severe skin reactions

Acute or chronic rheumatoid arthiritis Systemic and discoid lupus erythamatosus

CNS:

irritability, nervousness, emotional changes, nightmares, psychosis, headache, dizziness, vertigo, tinnitus, nystagmus, nerve deafness, convulsions, ataxia.

Cornea:

transcient edema, decreased corneal sensitivity. Optic disc pallor and atrophy, attentuation of retinal arterioles. Pericentral or paracentral scotoma with decreased visual acuity. Retinopathy, reading and seeing difficulties. Bleaching of hair, alopecia, pruritus, skin and mucosal pigmentation, skin eruptions.

Retinal or visual changes attributable to ant 4-aminoquinoline compound, hypersens to 4-aminoquinline compounds; long term therapy in children.

Special precautions:

Perform periodic blood cell counts during prolonged therapy. If severe blood disorder appears, consider discontinuation. Use caution in G-6-PD deficiency. Use with caution in alcoholic patients Excercise care when given to patients receiving a drug with significant tendency to produce dermatitis. If severe toxic symptoms occur, administer ammonium chloride(8 g daily in divided doses for adults) 3 to 4 days a week for several months after therapy is stopped.

Indications:

Systemic llipus erythematous, rheumatoid arthritis, malaria.

Dosage:

Rheumatoid arthritis- Initial- adults- 400 to 600 mg daily,taken with meal or glass of milk

Maintenance- Adults- After good response,reduce dosage by 50% at a level of 200 to 400 mg daily.

Children- a dose of 3 to 5 mg/kg/day upto a maximum of 400 mg/day( given once or twicw daily). Do not exceed a dose of 7 mg/kg/day.

Lupus erythematosis- 400mg once or twice daily in adults,continued for several weeks or months.

Maintenace dose- 200 to 400 mg daily. Retinopathy is reported if the maintenance dose is exceeded.

Pharmacology:

A 4-aminoquinoline compd with antimalarial actions similar to those of chloroquine. It seem to act by suppression of formation of antigens responsible for hypersensitivity reactions.

Pharmacokinetics:

Readily absorbed from GI tract,peak plasma concentrations occur in 1 to 3 hours. The drug concentrates in the liver, spleen, kidney, heart, lung and the brain. About 50% of the unchanged is excreted in the urine.

Not significant.

Pregnancy:

Avoid use during pregnancy

Lactation- A very low concentration of the drug appears in the breast milk.

Children:

Are very sensitive to the drug. Use with extreme caution.