Mepron Drug Information

Dosage for the Prevention of P. jirovecii Pneumonia The recommended oral dosage is 1,500 mg (10 mL) once daily administered with food.

Dosage for the Treatment of Mild-to-Moderate

P. jirovecii Pneumonia The recommended oral dosage is 750 mg (5 mL) twice daily (total daily dose = 1,500 mg) administered with food for 21 days.

Important Administration Instructions Administer

MEPRON oral suspension with food to avoid low plasma atovaquone concentrations that may limit response to therapy. MEPRON Foil Pouch • Open each 5-mL pouch by folding along the dotted line and tearing open at horizontal slit as directed by arrow on pouch. • For a 5-mL dose, take entire contents either by placing directly into the mouth or by dispensing into a dosing spoon (5 mL) or cup prior to administration by mouth. • For a 10-mL dose, take the entire contents of 2 pouches. MEPRON Bottle Shake bottle gently before administering the recommended dosage.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice. Additionally, because many subjects who participated in clinical trials with MEPRON had complications of advanced human immunodeficiency virus (HIV) disease, it was often difficult to distinguish adverse reactions caused by MEPRON from those caused by underlying medical conditions. PCP Prevention Trials In 2 clinical trials, MEPRON oral suspension was compared with dapsone or aerosolized pentamidine in HIV-1–infected adolescent (13 to 18 years) and adult subjects at risk of PCP (CD4 count <200 cells/mm 3 or a prior episode of PCP) and unable to tolerate TMP-SMX.

Adverse reaction data were collected only for adverse reactions requiring discontinuation of treatment, which occurred at similar frequencies in subjects treated with MEPRON oral suspension or dapsone ( Table 1 ). Among subjects taking neither dapsone nor atovaquone at enrollment (n = 487), adverse reactions requiring discontinuation of treatment occurred in 43% of subjects treated with dapsone and 20% of subjects treated with MEPRON oral suspension. Gastrointestinal adverse reactions (nausea, diarrhea, and vomiting) were more frequently reported in subjects treated with MEPRON oral suspension ( Table 1 ).

Table 1. Percentage (>2%) of Subjects with Selected Adverse Reactions Requiring Discontinuation of Treatment in the Dapsone Comparative PCP Prevention Trial Aerosolized Pentamidine Comparative Trial: In the aerosolized pentamidine comparative trial (n = 549), the majority of subjects were white (79%), male (92%), and were primary prophylaxis patients at enrollment (58%); the mean age was 38 years. Table 2 summarizes the clinical adverse reactions reported by ≥20% of the subjects receiving either the 1,500-mg dose of MEPRON oral suspension or aerosolized pentamidine.

Rash occurred more often in subjects treated with MEPRON oral suspension (46%) than in subjects treated with aerosolized pentamidine (28%). Treatment‑limiting adverse reactions occurred in 25% of subjects treated with MEPRON oral suspension 1,500 mg once daily and in 7% of subjects treated with aerosolized pentamidine. The most frequent adverse reaction requiring discontinuation of dosing in the group receiving aerosolized pentamidine was bronchospasm (2%).

Table 2. Percentage (≥20%) of Subjects with Selected Adverse Reactions in the Aerosolized Pentamidine Comparative PCP Prevention Trial % of subjects receiving the recommended dose of MEPRON oral suspension (1,500 mg once daily) included vomiting, sweating, flu syndrome, sinusitis, pruritus, insomnia, depression, and myalgia. PCP Treatment Trials Safety information is presented from 2 clinical efficacy trials of the MEPRON tablet formulation: 1 a randomized, double‑blind trial comparing MEPRON tablets with TMP‑SMX in subjects with acquired immunodeficiency syndrome (AIDS) and mild‑to‑moderate PCP ≤45 mm Hg and PaO 2 ≥60 mm Hg on room air; 2 a randomized, open-label trial comparing MEPRON tablets with intravenous (IV) pentamidine isethionate in subjects with mild‑to‑moderate PCP who could not tolerate trimethoprim or sulfa antimicrobials.

Table 3 summarizes all clinical adverse reactions reported by ≥10% of the trial population regardless of attribution. Nine percent of subjects who received MEPRON and 24% of subjects who received TMP‑SMX discontinued therapy due to an adverse reaction. Among the subjects who discontinued, 4% of subjects receiving MEPRON and 8% of subjects in the TMP-SMX group discontinued therapy due to rash.

The incidence of adverse reactions with MEPRON oral suspension at the recommended dose (750 mg twice daily) was similar to that seen with the tablet formulation. Table 3. Percentage (≥10%) of Subjects with Selected Adverse Reactions in the TMP-SMX Comparative PCP Treatment Trial 9 Two percent of subjects treated with MEPRON and 7% of subjects treated with TMP‑SMX had therapy prematurely discontinued due to elevations in ALT/AST.

Table 4 summarizes the clinical adverse reactions reported by ≥10% of the primary therapy trial population regardless of attribution. Fewer subjects who received MEPRON reported adverse reactions than subjects who received pentamidine (63% vs. 72%). However, only 7% of subjects discontinued treatment with MEPRON due to adverse reactions, while 41% of subjects who received pentamidine discontinued treatment for this reason.

Of the 5 subjects who discontinued therapy with MEPRON, 3 reported rash (4%). Rash was not severe in any subject. The most frequently cited reasons for discontinuation of pentamidine therapy were hypoglycemia (11%) and vomiting (9%).

Table 4. One subject (1%) receiving MEPRON had elevated creatinine and BUN levels and 1 subject (1%) had elevated amylase levels. In this trial, elevated levels of amylase occurred in subjects (8% versus 4%) receiving MEPRON tablets or pentamidine, respectively.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of MEPRON oral suspension. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Blood and Lymphatic System Disorders Methemoglobinemia, thrombocytopenia.

Immune System Disorders Hypersensitivity reactions including angioedema, bronchospasm, throat tightness, and urticaria. Eye Disorders Vortex keratopathy. Gastrointestinal Disorders Pancreatitis.

Hepatobiliary Disorders Hepatitis, fatal liver failure. Skin and Subcutaneous Tissue Disorders Erythema multiforme (EM), Stevens-Johnson syndrome (SJS), skin desquamation, and drug reaction with eosinophilia and systemic symptoms (DRESS). Renal and Urinary Disorders Acute renal impairment.

Rifampin/Rifabutin

Concomitant administration of rifampin or rifabutin and MEPRON oral suspension is known to reduce atovaquone concentrations. Concomitant administration of MEPRON oral suspension and rifampin or rifabutin is not recommended.

Tetracycline

Concomitant administration of tetracycline and MEPRON oral suspension has been associated with a reduction in plasma concentrations of atovaquone. Caution should be used when prescribing tetracycline concomitantly with MEPRON oral suspension. Monitor patients for potential loss of efficacy of MEPRON if coadministration is necessary.

Metoclopramide Metoclopramide may reduce the bioavailability of atovaquone and should be used only if other antiemetics are not available.

Indinavir

Concomitant administration of atovaquone and indinavir did not result in any change in the steady-state AUC and C max of indinavir but resulted in a decrease in the C trough of indinavir. Caution should be exercised when prescribing MEPRON oral suspension with indinavir due to the decrease in trough concentrations of indinavir.

Pregnancy Risk Summary Available data from postmarketing experience with use of MEPRON in pregnant women are insufficient to identify a drug-associated risk for major birth defects, miscarriage, or adverse maternal or fetal outcomes. Pregnant women with HIV who are infected with PCP are at increased risk of adverse pregnancy outcomes (see Clinical Considerations). Atovaquone given orally by gavage to pregnant rats and rabbits during organogenesis did not cause fetal malformations at plasma concentrations up to 3 times and 0.5 times, respectively, the estimated human exposure based on steady-state plasma concentrations (see Data).

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the background risk of major birth defects and miscarriage in clinically recognized pregnancies is respectively.

Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk: Pregnant women with HIV who are infected with PCP are at increased risk of severe illness and maternal death associated with PCP compared with non-pregnant women. Data Animal Data: Atovaquone administered in oral doses of 250, 500, and 1,000 mg/kg/day to pregnant rats during organogenesis (Gestation Day 6 to GD15) did not cause maternal or embryo-fetal toxicity at doses up to 1,000 mg/kg/day corresponding to maternal plasma concentrations approximately 3 times the estimated human exposure during the treatment of PCP based on steady-state plasma concentrations. In pregnant rabbits, atovaquone administered in oral doses of 300, 600, and 1,200 mg/kg/day during organogenesis (GD6 to GD18) caused decreased fetal body length at a maternally toxic dose of 1,200 mg/kg/day corresponding to a plasma concentration that is approximately 0.5 times the estimated human exposure based on steady-state plasma concentrations.

In a pre- and post-natal study in rats, atovaquone administered in oral doses of 250, 500, and 1,000 mg/kg/day from GD15 until Lactation Day (LD) 20 did not impair the growth or developmental effects in first generation offspring at doses up to 1,000 mg/kg/day corresponding to approximately 3 times the estimated human exposure based on steady-state plasma concentrations during the treatment of PCP. Atovaquone crossed the placenta and was present in fetal rat and rabbit tissue.

Pediatric Use Evidence of safety and effectiveness in pediatric patients (aged 12 years and younger) has not been established. In a trial of MEPRON oral suspension administered once daily with food for 12 days to 27 HIV-1–infected, asymptomatic infants and children aged between 1 month and 13 years, the pharmacokinetics of atovaquone were age-dependent. The average steady-state plasma atovaquone concentrations in the 24 subjects with available concentration data are shown in Table 5.

Table 5. Average Steady-State Plasma Atovaquone Concentrations in Pediatric Subjects C ss = Concentration at steady state.

MEPRON oral suspension is contraindicated in patients who develop or have a history of hypersensitivity reactions to atovaquone or any of the components of MEPRON. Known serious allergic/hypersensitivity reaction to atovaquone or any of the components of MEPRON.

Overdoses up to 31,500 mg of atovaquone have been reported. In one such patient who also took an unspecified dose of dapsone, methemoglobinemia occurred. Rash has also been reported after overdose.

There is no known antidote for atovaquone, and it is currently unknown if atovaquone is dialyzable.