Arava, 20 mg 30 pcs.

Pharmic action:

Arava belongs to the class of basic antirheumatic drugs and has antiproliferative, immunomodulatory, immunosuppressive and anti-inflammatory properties.

The active metabolite of leflunomide A771726 inhibits the enzyme dehydrorotate dehydrogenase and has antiproliferative activity. Under in vitro conditions A771726 inhibits mitogen-induced proliferation and DNA synthesis of T-lymphocytes. The antiproliferative activity of A771726 seems to be manifested at the level of pyrimidine biosynthesis, since the addition of uridine to the cell culture eliminates the inhibitory effect of the metabolite A771726.

It was shown using radioisotope ligands that A771726 selectively binds to the enzyme dehydrorotate dehydrogenase, which explains its ability to inhibit this enzyme and lymphocyte proliferation at the G1 stage. Lymphocyte proliferation is one of the key stages in the development of rheumatoid arthritis.

A771726 simultaneously inhibits the expression of interleukin-2 receptors (CB-25) and Ki-67 and PCNA cell-cycle-related core antigens.

Therapeutic effects of leflunomide have been shown in several experimental models of autoimmune diseases, including rheumatoid arthritis.

Leflunomide reduces symptoms and slows the progression of joint damage in the active form of rheumatoid arthritis.
The therapeutic effect is usually seen after 4-6 weeks and can build up further over 4-6 months.

Indications

As a base treatment for adult patients with active rheumatoid arthritis in order to reduce the symptoms of the disease and delay the development of structural damage to the joints.

The active form of psoriatic arthritis.

Active ingredient

Composition

Active substance:

leflunomide 10 mg.

How to take, the dosage

The use of Arava should begin under the supervision of a physician experienced in the treatment of rheumatoid and psoriatic arthritis.

The treatment begins with a shock dose of 100 mg daily for 3 days. As a maintenance dose in rheumatoid arthritis, a dose of 10 to 20 mg once daily is recommended; in psoriatic arthritis, 20 mg once daily.

Therapeutic effect is seen 4 to 6 weeks after the start of therapy and may increase during 4 to 6 months. Tablets should be swallowed whole with plenty of fluid, regardless of meals. No dose adjustment is required for patients over 65 years of age and in patients with mild renal impairment.

Interaction

An increase in adverse events may occur in the case of recent or concomitant use of hepatotoxic (including alcohol) or hematotoxic and immunosuppressive drugs or when these drugs are started after treatment with leflunomide without a “washout” procedure (see “Special Precautions”).

In rheumatoid arthritis patients, no pharmacokinetic interaction has been found between leflunomide (10 to 20 mg daily) and methotrexate (10 to 25 mg weekly).

Patients taking leflunomide are advised not to give colestyramine or activated charcoal, as this leads to a rapid and significant decrease in plasma concentrations of A771726 (the active metabolite of leflunomide). This is thought to be due to impaired recirculation of A771726 in the liver and small intestine and/or impaired gastrointestinal dialysis.

If a patient is already taking nonsteroidal anti-inflammatory drugs (NSAIDs) and/or corticosteroids, they can be continued after starting leflunomide treatment.

The enzymes involved in the metabolism of leflunomide and its metabolites are not exactly known. An in vivo study of its interaction with cimetidine (a non-specific cytochrome P450 inhibitor) showed no significant interaction. After concomitant administration of a single dose of leflunomide to subjects receiving multiple doses of rifampicin (a non-specific cytochrome P450 inducer), peak levels of A771726 increased by approximately 40%, whereas the area under the concentration-time curve did not change significantly. The mechanism of this effect is not clear.

In vitro studies have shown that A771726 inhibits cytochrome P4502C9 (CYP2C9) activity. No problems have been observed in clinical trials when leflunomide and NSAIDs metabolized by CYP2C9 are coadministered. Particular caution should be exercised in giving
leflunomide together with other non-NSAIDs metabolized by CYP2C9, such as phenytoin, warfarin, and tolbutamide. Increased prothrombin time has been reported with concomitant administration of leflunomide and warfarin.
In a study in which leflunomide was given to healthy female volunteers together with triphasic oral contraceptives containing 30 µg ethinyl estradiol, no reduction in the contraceptive effect of the pills was found, and the pharmacokinetics of A771726 fell completely within the intended range.

There is currently no information regarding the co-administration of leflunomide with antimalarials used in rheumatology (e.g., chloroquine and hydroxychlorine), Au drugs (intramural or oral), D-penicillamine, azathioprine and other immunosuppressive drugs (excluding methotrexate). The risks associated with combination therapy are unknown, especially with long-term treatment. Since this type of therapy may lead to additional or even synergistic toxicity (e.g., hepato- or hematoxicity), combinations of this drug with other basal drugs (e.g., methotrexate) are undesirable. Recent concomitant or subsequent use of potentially myelotoxic agents may be associated with a greater risk of hematologic effects. Immunosuppressants increase the risk of infections as well as malignant, especially lymphoproliferative diseases.

Vaccination

There are no clinical data regarding the efficacy and safety of vaccination in the setting of leflunomide treatment. However, vaccination with live vaccines is not recommended. The long elimination half-life of Arava should be considered when planning for live vaccination after withdrawal of Arava.

Special Instructions

Arava should only be prescribed to patients after a thorough medical examination.

Before starting treatment with the drug Arava, it is necessary to keep in mind the possible increase in side effects in patients who previously received other basal agents for rheumatoid arthritis, which have hepatotoxic effects.
The active metabolite of leflunomide, A771726, has a long half-life, usually ranging from 1 to 4 weeks. Because of the long half-life of the active metabolite of leflunomide, A771726, even when treatment with leflunomide is stopped, serious adverse effects may occur or persist (e.g., hepatotoxicity, hematoxicity, or allergic reactions, see below). In this case, a “washout” procedure should be performed.The procedure may be repeated for clinical indications. If severe immunological/allergic reactions such as Stevens-Johnson syndrome or Lyell syndrome are suspected, a complete “washout” procedure must be performed.

Therefore, if such toxicity occurs or if you switch to another basal drug (e.g. methotrexate) after treatment with leflunomide, a “washout” procedure (see below) should be performed.

Hepatic reactions

Because the active metabolite of leflunomide, A771726, is bound to proteins and is eliminated by hepatic metabolism and bile secretion, it is thought that plasma levels of A771726 may be elevated in patients with hypoproteinemia. Arava is contraindicated in patients with severe hypoproteinemia or liver dysfunction. (See Contraindications.).

Rare cases of severe liver damage, occasionally fatal, have been reported when treated with leflunomide. Most of these cases have occurred within the first six months of treatment. Although a causal relationship of these adverse events to leflunomide has not been established, and several additional suspicious factors were present in most cases, accurate adherence to treatment monitoring recommendations is considered mandatory.

ALT levels should be checked before starting leflunomide therapy and then every 2 weeks for the first 6 months of treatment, with a follow-up check once every 6-8 weeks.

There are the following recommendations for dosing adjustment or discontinuation depending on the severity and persistence of ALT elevation.

If ALT is confirmed to be 2-3 times the upper limit of ALT, a dose reduction from 20 mg to 10 mg per day may allow continued use of leflunomide, provided that it is carefully monitored.

If 2-3 times the upper limit of ALT persists, or if there is a confirmed ALT elevation of more than 3 times the upper limit of normal, leflunomide should be stopped and a “flushing” procedure should be initiated.
Because of possible additional hepatotoxic effects, it is recommended that alcohol should not be taken while receiving leflunomide.

Hematologic reactions

A complete clinical blood count, including determination of the white blood cell count and platelet count, should be performed before treatment with leflunomide, and every 2 weeks during the first 6 months of treatment and every 6-8 weeks thereafter.

In patients with pre-existing anemia, leukopenia and/or thrombocytopenia as well as in patients with bone marrow dysfunction or at risk of developing such dysfunction, there is an increased risk of hematological disorders. If this occurs, a “washout” procedure should be used to reduce plasma levels of A771726.

In the event of serious hematologic reactions, including pancytopenia, Arava and any other concomitant medication that inhibits bone marrow hematopoiesis should be stopped and a “wash” procedure should be initiated.

Combined use with other treatments

. There is currently no information yet regarding the co-administration of leflunomide with antimalarials used in rheumatology (e.g., chloroquine and hydroxychloroquine), intramuscular or oral gold drugs, D-penicillamine, azathioprine, and other immunosuppressive agents (excluding methotrexate). There are no known risks associated with the administration of combination therapy, especially with long-term treatment. Since this type of therapy may lead to additional or even synergistic toxicity (e.g., hepatotoxicity or hematotoxicity), combinations of this drug with other baseline drugs (e.g., methotrexate) are not advisable.

Transitioning to other treatments

Because leflunomide persists in the body for a long time, switching to another baseline drug (e.g., methotrexate) without a proper “washout” procedure can increase the potential for additional risks even long after transition (e.g., kinetic interaction, organ toxicity).

Like, recent treatment with hepatotoxic or hematotoxic drugs (e.g., methotrexate) can lead to increased adverse events, so starting leflunomide treatment should carefully consider all the positive and negative aspects associated with taking this medication.

Skin reactions

Leflunomide should be stopped if ulcerative stomatitis develops.

Very rare cases of Stevens-Johnson syndrome or toxic epidermal necrolysis have been reported in patients receiving leflunomide. In case of skin and/or mucous membrane reactions, the administration of Arava and any other related drug should be stopped and a “washout” procedure should be initiated immediately. It is necessary to achieve complete elimination of the drug from the body. In such cases, reapplication of the drug is contraindicated.

Infections

Leflunomide-like drugs with immunosuppressive properties are known to make patients more susceptible to various types of infections, including opportunistic infections (infections caused by fungi and microorganisms that can only cause infections when immunity is reduced). Emerging infectious diseases are usually severe and require early and intensive treatment. If a severe infectious disease occurs, it may be necessary to interrupt treatment with leflunomide and begin a “washout” procedure.

Patients who test positive for tuberculin should be closely monitored because of the risk of reactivation of tuberculosis.

Respiratory reactions

Rare cases of interstitial lung disease have been reported with leflunomide therapy. Symptoms such as cough and dyspnea may be reasons for discontinuing leflunomide.

Hypertension

Hypertension should be monitored before starting treatment with leflunomide and periodically thereafter.

Interactions

Precaution should be exercised when prescribing drugs that are metabolized by CYP2C9 (phenytoin, warfarin, tolbutamide) except NSAIDs (nonsteroidal anti-inflammatory drugs).

Recommendations for men

There are no data on the risk of fetotoxicity (associated with toxic effects of the drug on paternal sperm) when leflunomide is used by men. Experimental data in this direction have not been conducted. To minimize the possible risk, men should stop taking leflunomide and use colestiramine 8 g 3 times a day for 11 days or 50 g of powdered activated charcoal 4 times a day for 11 days when planning to have a baby.

Contraindications

The drug Arava should not be used in patients with hypersensitivity to leflunomide or any other component of the drug.
The drug is contraindicated:
– in patients with impaired liver function;
– in patients with severe immunodeficiency (e.g., AIDS);
– Patients with significant hemopoiesis disorders or with severe anemia, leukopenia or thrombocytopenia due to other causes (except rheumatoid arthritis).
– Patients with severe, uncontrollable infections. – in patients with moderate or severe renal insufficiency (due to little experience of clinical monitoring);
– in patients with severe hypoproteinemia (e.g., in nephrotic syndrome);
– in pregnant women or women of childbearing age who do not use reliable contraception during treatment with leflunomide and then as long as plasma level of active metabolite remains above 0.02 mg/l (see “Pregnancy and lactation”). “Pregnancy and breastfeeding”). Pregnancy should be excluded before starting treatment with leflunomide.

Leflunomide is contraindicated during breastfeeding (see “Pregnancy and breastfeeding.)

Men treated with leflunomide should be warned about the possible fetotoxic effects of the drug (due to its possible effect on the sperm of the father) and the need for reliable contraception.

Arava is not recommended for use in patients younger than 18 years of age because there are no data on efficacy and safety in this group of patients.

Side effects

Classification of the estimated frequency of adverse events:
very frequent (more than 1/10), frequent (more than 1/100 but less than 1/10), infrequent (more than 1/1000 but less than 1/100), rare (more than 1/10000 but less than 1/1000), very rare (less than 1/10000), unknown (cannot be estimated based on available data).

– Cardiovascular
Frequent: moderate increase in blood pressure.
Rare: marked increase in blood pressure

– Gastrointestinal tract
Frequent: diarrhea, nausea, vomiting, diseases of the oral mucosa (eg, aphthous stomatitis, ulcerated lips), pain in the abdomen.
Infrequent: taste disorders
Very rare: pancreatitis

– Respiratory system and mediastinal disorders
Rare: interstitial pulmonary process (including interstitial pneumonia), with possible fatal outcome.

– Metabolic disorders
Frequent: increased creatine phosphokinase (CPK)
Infrequent: hypokalemia, hyperlipidemia, hypophosphatemia.
Rare: increased lactate dehydrogenase (LDH)
Frequent unknown: hypouricemia

– Nervous system
Frequent: headache, dizziness, paresthesias.
Infrequent: anxiety.
Very rare: peripheral neuropathy

– Musculoskeletal system
Frequent: tendovaginitis.
Infrequent: tendon rupture

– Skin and derivatives
Frequent: increased hair loss, eczema, rash (including maculopapular rash), itching, dry skin.
Infrequent: urticaria
Very rare: toxic epidermal necrolysis (Lyell’s syndrome), erythema multiforme, Stevens-Johnson syndrome.

– Immune system
Frequent: mild allergic reactions.
Very rare: serious anaphylactic/anaphylactoid reactions, vasculitis, including cutaneous necrotic vasculitis.

– Infections and invasions
Rare: development of severe infections, including opportunistic infections and sepsis, which can be fatal.
Possible infections (particularly rhinitis, bronchitis and pneumonia) may increase.

– Blood and lymphatic system
Frequent: leukopenia (leukocytes > 2000/μl).
Infrequent: anemia, minor thrombocytopenia (platelets < 100,000/μl).
Rare: pancytopenia (probably due to antiproliferative action), leukopenia (leukocytes < 2000/μl), eosinophilia.
Very rare: agranulocytosis.
Recent, concomitant, or subsequent use of potentially myelotoxic agents may be associated with a greater risk of hematologic effects.

– Hepato-biliary system
Frequent: increased activity of “hepatic” transaminases (especially alanine aminotransferase (ALT)), less frequently, gamma-glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP), hyperbilirubinemia.
Rare: hepatitis, jaundice/cholestasis.
Very rare: severe liver damage such as liver failure, acute liver necrosis, which can be fatal;

– Changes of general nature
Frequent: anorexia, weight loss (usually mild), asthenia.

– Reproductive system disorders:
Frequent unknown: slight decrease in sperm concentration, total sperm count and motility

– Renal and urinary tract disorders:
Frequency unknown: renal failure

– Other
The risk of malignant, especially lymphoproliferative diseases is increased with some immunosuppressive drugs.

Overdose

Symptoms

There have been reports of chronic overdose in patients receiving leflunomide at doses up to 5 times the recommended daily dose, as well as reports of acute overdose in adults and children. In most cases of overdose, no adverse events were reported. The resulting adverse events were comparable to the safety profile of leflunomide. The most frequently observed adverse events were diarrhea, abdominal pain, leukopenia, anemia, and increased liver function tests.

Treatment

In case of overdose or toxicity, colethiramine or activated charcoal are recommended to speed up clearing the body.

Colestyramine taken orally by three healthy volunteers at 8 g three times a day for 24 hours reduced plasma levels of A771726 by about 40% after 24 hours and by 49% to 65% after 48 hours.

The administration of activated charcoal (powder made into suspension) orally or through a gastric tube (50 g every 6 hours for 24 hours) was shown to reduce plasma concentrations of the active metabolite A771726 by 37% after 24 hours and by 48% after 48 hours.
These “washing” procedures can be repeated for clinical indications.

Studies with hemodialysis and CAPD (chronic ambulatory peritoneal dialysis) indicate that A771726, the major metabolite of leflunomide, is not able to be excreted by dialysis.