Lefluniclo (Page 4 of 8)

8.2 Lactation

Risk Summary

Clinical lactation studies have not been conducted to assess the presence of leflunomide tablets in human milk, the effects of leflunomide tablets on the breastfed child, or the effects of leflunomide tablets on milk production. Because of the potential for serious adverse reactions in a breastfed infant from leflunomide tablets, advise a nursing woman to discontinue breastfeeding during treatment with leflunomide tablets.

8.3 Females and Males of Reproductive Potential

Leflunomide tablets may cause fetal harm when administered during pregnancy. Advise females of the potential risk to the fetus. Advise females to notify their healthcare provider immediately if pregnancy occurs or is suspected during treatment [see Use in Specific Populations (8.1)]. Women receiving leflunomide tablets treatment who wish to become pregnant should discontinue leflunomide tablets and undergo an accelerated drug elimination procedure to achieve plasma teriflunomide concentrations of less than 0.02 mg/L (0.02 mcg/mL) [see Warnings and Precautions (5.3)].

Pregnancy Testing

Exclude pregnancy in females of reproductive potential before starting treatment with leflunomide tablets.

Contraception

Females

Advise females of reproductive potential to use effective contraception during treatment with leflunomide tablets and while undergoing a drug elimination procedure until verification that the plasma teriflunomide concentration is less than 0.02 mg/L [see Warnings and Precautions (5.3)].

8.4 Pediatric Use

The safety and effectiveness of leflunomide tablets in pediatric patients have not been established.

The safety and effectiveness of leflunomide tablets in the treatment of polyarticular course juvenile idiopathic arthritis (JIA) was evaluated in a single multicenter, double-blind, active-controlled trial in 94 pediatric patients (1:1 randomization) with polyarticular course juvenile idiopathic arthritis (JIA) as defined by the American College of Rheumatology (ACR). In this population, leflunomide tablets treatment was found not to be effective.

The safety of leflunomide tablets was studied in 74 patients with polyarticular course JIA ranging in age from 3 to 17 years (47 patients from the active-controlled study and 27 from an open-label safety and pharmacokinetic study). The most common adverse events included abdominal pain, diarrhea, nausea, vomiting, oral ulcers, upper respiratory tract infections, alopecia, rash, headache, and dizziness. Less common adverse events included anemia, hypertension, and weight loss. Fourteen pediatric patients experienced ALT and/or AST elevations, nine between 1.2 and 3-fold the upper limit of normal, five between 3 and 8-fold the upper limit of normal.

8.5 Geriatric Use

Of the total number of subjects in controlled clinical trials (Trials 1, 2, and 3) of leflunomide tablets, 234 subjects were 65 years and over [see Clinical Studies (14)]. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out. No dosage adjustment is needed in patients over 65.

8.6 Hepatic Impairment

Dedicated studies of the effect of hepatic impairment on leflunomide pharmacokinetics have not been conducted. Given the need to metabolize leflunomide into the active species, the role of the liver in drug elimination/recycling, and the possible risk of increased hepatic toxicity, the use of leflunomide tablets in patients with hepatic impairment is not recommended.

8.7 Renal Impairment

Dedicated studies of the effect of renal impairment on leflunomide pharmacokinetics have not been conducted. Given that the kidney plays an important role in drug elimination, caution should be used when leflunomide tablet is administered to these patients.

10 OVERDOSAGE

There have been reports of chronic overdose in patients taking leflunomide tablets at daily dose up to five times the recommended daily dose and reports of acute overdose in adults and children. Adverse events were consistent with the safety profile for leflunomide tablets [See Adverse Reactions (6)]. The most frequent adverse events observed were diarrhea, abdominal pain, leukopenia, anemia and elevated liver function tests.

In the event of a significant overdose or toxicity, perform an accelerated drug elimination procedure to accelerate elimination [see Warnings and Precautions (5.3)].

Studies with both hemodialysis and CAPD (chronic ambulatory peritoneal dialysis) indicate that teriflunomide, the primary metabolite of leflunomide, is not dialyzable [See Clinical Pharmacology (12.3)].

11 DESCRIPTION

Leflunomide USP is a pyrimidine synthesis inhibitor. The chemical name for leflunomide is N-(4´-trifluoromethylphenyl)-5-methylisoxazole-4-carboxamide. It has an empirical formula C12 H9 F3 N2 O2 , a molecular weight of 270.2 and the following structural formula:

Image
(click image for full-size original)

Leflunomide USP is available for oral administration as film coated tablets containing 10, 20 mg of active drug. Combined with leflunomide are the following inactive ingredients: colloidal silicon dioxide, crospovidone, hypromellose, lactose monohydrate, magnesium stearate, corn starch, HPMC 2910/Hypromellose USP (6 mPas), Titanium Dioxide USP, Macrogol/PEG 6000 NF, Talc USP and Iron Oxide Yellow NF (20 mg tablet only).

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Leflunomide is an isoxazole immunomodulatory agent that inhibits dihydroorotate dehydrogenase (a mitochondrial enzyme involved in de novo pyrimidine synthesis) and has antiproliferative activity. Several in vivo and in vitro experimental models have demonstrated an anti-inflammatory effect.

12.3 Pharmacokinetics

Following oral administration, leflunomide is metabolized to an active metabolite, teriflunomide, which is responsible for essentially all of leflunomide’s in vivo activity. Plasma concentrations of the parent drug, leflunomide, have been occasionally seen at very low concentrations. Studies of the pharmacokinetics of leflunomide have primarily examined the plasma concentrations of the active metabolite, teriflunomide.

Image
(click image for full-size original)

Absorption

Following oral administration, peak teriflunomide concentrations occurred between 6 to 12 hours after dosing. Due to the very long half-life of teriflunomide (18 to 19 days), a loading dose of 100 mg for 3 days was used in clinical studies to facilitate the rapid attainment of steady-state teriflunomide concentrations. Without a loading dose, it is estimated that attainment of steady- state plasma concentrations would require about two months of dosing. The resulting plasma concentrations following both loading doses and continued clinical dosing indicate that plasma teriflunomide concentrations are dose proportional.

Effect of Food

Co-administration of leflunomide tablets with a high fat meal did not have a significant impact on teriflunomide plasma concentrations.

Distribution

Teriflunomide is extensively bound to plasma protein (>99%) and is mainly distributed in plasma. The volume of distribution is 11 L after a single intravenous (IV) administration.

Elimination

Teriflunomide, the active metabolite of leflunomide, has a median half-life of 18 to 19 days in healthy volunteers. The elimination of teriflunomide can be accelerated by administration of cholestyramine or activated charcoal. Without use of an accelerated drug elimination procedure, it may take up to 2 years to reach plasma teriflunomide concentrations of less than 0.02 mg/L, due to individual variation in drug clearance [see Warnings and Precautions (5.3)]. After a single IV administration of the metabolite (teriflunomide), the total body clearance of teriflunomide was 30.5 mL/h.

Metabolism

In vitro inhibition studies in human liver microsomes suggest that cytochrome P450 (CYP) 1A2, 2C19 and 3A4 are involved in leflunomide metabolism. In vivo , leflunomide is metabolized to one primary (teriflunomide) and many minor metabolites. In vitro , teriflunomide is not metabolized by CYP450 or flavin monoamine oxidase enzymes. The parent compound is rarely detectable in plasma.

Excretion

Teriflunomide, the active metabolite of leflunomide, is eliminated by direct biliary excretion of unchanged drug as well as renal excretion of metabolites. Over 21 days, 60.1% of the administered dose is excreted via feces (37.5%) and urine (22.6%). After an accelerated elimination procedure with cholestyramine, an additional 23.1% was recovered (mostly in feces).

Studies with both hemodialysis and CAPD (chronic ambulatory peritoneal dialysis) indicate that teriflunomide is not dialyzable.

Specific Populations

Gender. Gender has not been shown to cause a consistent change in the in vivo pharmacokinetics of teriflunomide.

Smoking. A population based pharmacokinetic analysis of the clinical trial data indicates that smokers have a 38% increase in clearance over non-smokers; however, no difference in clinical efficacy was seen between smokers and nonsmokers.

Drug Interaction Studies

Drug interaction studies have been conducted with both leflunomide and with its active metabolite, teriflunomide, where the metabolite was directly administered to the test subjects.

The Potential Effect of Other Drugs on Leflunomide tablets

  • Potent CYP and transporter inducers:

Following concomitant administration of a single dose of leflunomide tablets to subjects receiving multiple doses of rifampin, teriflunomide peak concentrations were increased (~40%) over those seen when leflunomide tablets was given alone [see Drug Interactions (7)].

  • An in vivo interaction study with leflunomide tablets and cimetidine (non-specific weak CYP inhibitor) has demonstrated a lack of a significant impact on teriflunomide exposure.

The Potential Effect of leflunomide tablets on Other Drugs

  • CYP2C8 Substrates

There was an increase in mean repaglinide Cmax and AUC (1.7-and 2.4-fold, respectively), following repeated doses of teriflunomide and a single dose of 0.25 mg repaglinide, suggesting that teriflunomide is an inhibitor of CYP2C8 in vivo. The magnitude of interaction could be higher at the recommended repaglinide dose [see Drug Interactions (7)].

  • CYP1A2 Substrates

Repeated doses of teriflunomide decreased mean Cmax and AUC of caffeine by 18% and 55%, respectively, suggesting that teriflunomide may be a weak inducer of CYP1A2 in vivo.

  • OAT3 Substrates

There was an increase in mean cefaclor Cmax and AUC (1.43-and 1.54-fold, respectively), following repeated doses of teriflunomide, suggesting that teriflunomide is an inhibitor of organic anion transporter 3 (OAT3) in vivo [see Drug Interactions (7)]

  • BCRP and OATP1B1/1B3 Substrates

There was an increase in mean rosuvastatin Cmax and AUC (2.65-and 2.51-fold, respectively), following repeated doses of teriflunomide, suggesting that teriflunomide is an inhibitor of BCRP transporter and organic anion transporting polypeptide 1B1 and 1B3 (OATP1B1/1B3) [see Drug Interactions (7)].

  • Oral Contraceptives

There was an increase in mean ethinylestradiol Cmax and AUC0 to 24 (1.58-and 1.54-fold, respectively) and levonorgestrel Cmax and AUC0 to 24 (1.33-and 1.41-fold, respectively) following repeated doses of teriflunomide [see Drug Interactions (7)].

  • Teriflunomide did not affect the pharmacokinetics of bupropion (a CYP2B6 substrate), midazolam (a CYP3A4 substrate), S-warfarin (a CYP2C9 substrate), omeprazole (a CYP2C19 substrate), and metoprolol (a CYP2D6 substrate).
Image

All MedLibrary.org resources are included in as near-original form as possible, meaning that the information from the original provider has been rendered here with only typographical or stylistic modifications and not with any substantive alterations of content, meaning or intent.

This site is provided for educational and informational purposes only, in accordance with our Terms of Use, and is not intended as a substitute for the advice of a medical doctor, nurse, nurse practitioner or other qualified health professional.

Privacy Policy | Copyright © 2024. All Rights Reserved.