Hydroxychloroquine 300 mg · Tablets

Malaria — Hydroxychloroquine is a 4-aminoquinoline antimalarial [see Microbiology (12.4)] and antirheumatic agent.

Rheumatoid Arthritis, Systemic Lupus Erythematosus and Chronic Discoid Lupus Erythematosus

The mechanisms underlying the anti-inflammatory and immunomodulatory effects of hydroxychloroquine sulfate tablets in the treatment of rheumatoid arthritis, chronic discoid lupus erythematosus and systemic lupus erythematosus are not fully known.

Following oral administration, the whole blood concentration of hydroxychloroquine at steady state is dose proportional over a dose range from 200 mg daily to 400 mg daily of hydroxychloroquine tablets in rheumatoid arthritis and lupus patients.

Absorption — Following a single 200 mg oral dose of hydroxychloroquine sulfate tablets to healthy male volunteers, whole blood hydroxychloroquine Cmax was 129.6 ng/mL (plasma Cmax was 50.3 ng/mL) with Tmax of 3.3 hours (plasma Tmax 3.7 hours). Peak blood concentrations of metabolites were observed at the same time as peak levels of hydroxychloroquine. Mean absolute oral bioavailability is 79% (SD: 12%) in fasting conditions.

Peak blood concentrations ranged from 1161 ng/mL to 2436 ng/mL (mean 1918 ng/mL) following a single dose of 155 mg intravenous infusion and from 2290 ng/mL to 4211 ng/mL (mean 3312 ng/mL) following a single dose of 310 mg intravenous infusion in healthy subjects. Pharmacokinetic parameters were not significantly different over the therapeutic dose range of 155 mg and 310 mg, indicating linear kinetics.

In patients with rheumatoid arthritis, there was large variability as to the fraction of the dose absorbed (i.e. 30 to 100%), and mean hydroxychloroquine levels were significantly higher in patients with less disease activity.

Distribution — Hydroxychloroquine sulfate tablets is extensively distributed to tissues and has a large volume of distribution. Approximately 50% of hydroxychloroquine is bound to plasma proteins.

Metabolism — Significant levels of three metabolites, desethylhydroxychloroquine (DHCQ), desethylchloroquine (DCQ), and bidesethylhydroxychloroquine (BDCQ) were found in plasma and blood, with DHCQ being the major metabolite. In vitro, hydroxychloroquine is metabolized

mainly by CYP2C8, CYP3A4 and CYP2D6 as well as by FMO-1 and MAO-A.

Elimination / Excretion — Renal clearance in patients with rheumatoid arthritis treated with hydroxychloroquine sulphate tablets for at least 6 months was similar to that in single dose studies in healthy volunteers, suggesting that no change in clearance occurred with chronic dosing. Renal clearance of unchanged hydroxychloroquine was approximately 16% to 30% of the dose after oral and IV administration. Results following a single oral dose of a 200 mg tablet demonstrated a half-life of hydroxychloroquine about 40 days in whole blood. Following chronic oral administration of hydroxychloroquine, the absorption half-life of hydroxychloroquine was approximately 3 to 4 hours and the terminal half-life ranged from 40 to 50 days in whole blood. The effective half-life of hydroxychloroquine is likely to be shorter and steady state is achieved by 6 weeks following 400 mg daily oral administration in

Drug Interaction Studies — In vitro study suggestedthat hydroxychloroquine has a potential to inhibit CYP2D6, CYP3A4, Pglycoproteins (P-gp), MATE1 and MATE2-K.

In vitro study suggested that hydroxychloroquine has no significant potential to inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, and the main transporters OATP1B1, OATP1B3, OAT1, OAT3, OCT1, and OCT2. In vitro, hydroxychloroquine has no significant potential to