Instructions for Mefenamic acid film-coated tablets 500 mg No. 20
Composition
active ingredient: mefenamic acid;
1 tablet contains 500 mg of mefenamic acid;
Excipients: lactose monohydrate, sodium lauryl sulfate, povidone, crospovidone, pregelatinized starch, colloidal anhydrous silica, microcrystalline cellulose, talc, magnesium stearate, Opadry 200 white.
Dosage form
Film-coated tablets.
Main physicochemical properties: oblong tablets with a biconvex surface, with a score, coated with a white or almost white coating.
Pharmacotherapeutic group
Nonsteroidal anti-inflammatory and antirheumatic drugs. ATX code M01A G01.
Pharmacological properties
Pharmacodynamics.
Mefenamic acid is a nonsteroidal anti-inflammatory drug. The mechanism of anti-inflammatory action is due to the ability to inhibit the synthesis of inflammatory mediators (prostaglandins, serotonin, kinins, etc.), reduce the activity of lysosomal enzymes involved in the inflammatory reaction. Mefenamic acid stabilizes protein ultrastructures and cell membranes, reduces vascular permeability, disrupts oxidative phosphorylation processes, inhibits the synthesis of mucopolysaccharides, inhibits cell proliferation in the focus of inflammation, increases cell resistance and stimulates wound healing. Antipyretic properties are associated with the ability to inhibit the synthesis of prostaglandins and affect the thermoregulation center.
Mefenamic acid stimulates the formation of interferon.
In the mechanism of analgesic action, along with the effect on the central mechanisms of pain sensitivity, a significant role is played by the local effect on the focus of inflammation and the ability to inhibit the formation of algogens (kinins, histamine, serotonin).
Pharmacokinetics.
After oral administration, mefenamic acid is rapidly and fairly completely absorbed in the digestive tract. The maximum concentration in the blood is observed 2-4 hours after administration. The level in the blood is proportional to the dose. The equilibrium concentration (20 μg/ml) is determined on the 2nd day of administration (1 g 4 times a day). It is 90% bound to blood albumin. In the liver, it forms metabolites by oxidation, hydrolysis, and glucuronidation. The half-life (T1/2) is 2-4 hours. It is excreted from the body unchanged and in the form of metabolites mainly by the kidneys (67% of the dose) and with feces (20-25%).
Indication
Acute respiratory viral infections and influenza.
Low and medium intensity pain: muscular, joint, traumatic, dental, headache of various etiologies, postoperative and postpartum pain.
Primary dysmenorrhea. Dysfunctional menorrhagia, including that caused by the presence of intrauterine contraceptives, in the absence of pelvic organ pathology.
Inflammatory diseases of the musculoskeletal system: rheumatoid arthritis, rheumatism, Bechterew's disease.
Contraindication
Hypersensitivity to the components of the drug. Bronchospasm, angioedema, rhinitis, bronchial asthma or urticaria in history, which occurred after the use of acetylsalicylic acid or other non-steroidal anti-inflammatory drugs (NSAIDs). Simultaneous use of specific COX-2 inhibitors. Gastric and duodenal ulcer, including a history, inflammatory bowel diseases, diseases of the blood-forming organs, severe heart failure, severe liver or kidney dysfunction, gastrointestinal bleeding or perforation caused by taking non-steroidal anti-inflammatory drugs.
Interaction with other medicinal products and other types of interactions
Thiamine, pyridoxine hydrochloride, barbiturates, phenothiazine derivatives, narcotic analgesics, caffeine, diphenhydramine increase the analgesic effect of the drug.
The combined use of mefenamic acid and methotrexate increases the toxic effects of methotrexate.
Antihypertensive agents (ACE inhibitors and angiotensin II receptor antagonists): decreased antihypertensive effect.
Diuretics: decreased diuretic effect. Diuretics may increase the nephrotoxicity of NSAIDs.
Cardiac glycosides: NSAIDs may exacerbate heart failure, reduce glomerular filtration rate, and increase plasma levels of cardiac glycosides.
Cyclosporines: increased risk of nephrotoxicity.
Mifepristone: NSAIDs should not be taken for 8-12 days after taking mifepristone, NSAIDs may weaken the effect of mifepristone.
Corticosteroids: increased risk of gastrointestinal ulcers and bleeding.
Antiplatelet agents and selective serotonin reuptake inhibitors: increased risk of gastrointestinal bleeding.
Fluoroquinolones: NSAIDs increase the risk of seizures.
Aminoglycosides: NSAIDs increase the risk of nephrotoxic effects.
Tacrolimus: increased risk of nephrotoxic effects.
Zidovudine: NSAIDs increase the risk of hematological toxicity. There is an increased risk of joint hemorrhage and hematoma in HIV-positive hemophiliacs receiving concomitant zidovudine treatment.
Mefenamic acid increases the activity of oral anticoagulants, therefore, with their simultaneous use, the risk of bleeding increases.
Concomitant use with other nonsteroidal anti-inflammatory drugs increases the anti-inflammatory effect and the likelihood of gastrointestinal side effects.
Application features
The drug is prescribed with caution to patients with acute cardiovascular failure, arterial hypertension, and ischemic heart disease.
The drug is prescribed with caution to patients with epilepsy.
There are no special recommendations for the use of the drug in moderate liver or kidney dysfunction.
NSAIDs should be taken with caution in patients with a history of gastrointestinal diseases (ulcerative colitis, Crohn's disease), as exacerbation of the disease is possible.
Elderly patients are usually at increased risk of developing gastrointestinal side effects, so treatment should be started at the lowest dose.
Patients with systemic lupus erythematosus and mixed connective tissue diseases are at increased risk of aseptic meningitis.
Mefenamic acid should be discontinued at the first appearance of skin rash, mucosal lesions, or any other sign of hypersensitivity.
Taking mefenamic acid may impair female fertility and is not recommended for women trying to become pregnant.
Use during pregnancy or breastfeeding
The drug is not used in women during pregnancy or breastfeeding.
Ability to influence reaction speed when driving or using other mechanisms
Caution should be exercised when driving or operating machinery that requires increased attention, as sometimes the use of the drug can cause drowsiness, blurred vision, and seizures.
Method of administration and doses
The drug should be used under the supervision of a doctor, who determines the dose and duration of treatment. It is administered orally. The drug should be taken after meals, washed down with milk.
Adults and children over 12 years of age are prescribed 250-500 mg 3-4 times a day. According to indications and with good tolerability, the daily dose is increased to the maximum - 3000 mg, after achieving a therapeutic effect, the dose is reduced to 1000 mg/day.
Children aged 5 to 12 years - 250 mg 3-4 times a day.
The course of treatment for joint diseases can last from 20 days to 2 months or more. In the treatment of pain syndrome, the course of treatment lasts up to 7 days.
Children
The drug is contraindicated in children under 5 years of age.
Overdose
Symptoms: epigastric pain, nausea, vomiting, drowsiness. In severe cases, gastrointestinal bleeding, respiratory depression, hypertension, twitching of individual muscle groups, coma.
Treatment. There is no specific antidote. Gastric lavage with a suspension of activated charcoal. Alkalization of urine, forced diuresis. Symptomatic therapy. Hemosorption and hemodialysis are ineffective due to the strong binding of mefenamic acid to blood proteins.
Adverse reactions
From the digestive tract: epigastric pain, anorexia, heartburn, nausea, flatulence, vomiting, enterocolitis, colitis, steatorrhea, cholestatic jaundice, hepatitis, pancreatitis, hepatorenal syndrome, hemorrhagic gastritis, peptic ulcer, with or without bleeding. Gastrointestinal bleeding, dyspepsia, constipation, diarrhea. Increased levels of liver enzymes in the blood plasma.
Cardiovascular system: arterial hypertension, arrhythmia, rarely - congestive heart failure, peripheral edema, syncope, arterial hypotension, palpitations, shortness of breath.
From the respiratory system: dyspnea, bronchospasm.
From the urinary system: dysuria, cystitis. Renal dysfunction, albuminuria, hematuria, oliguria or polyuria, renal failure, including papillary necrosis, acute interstitial nephritis, nephrotic syndrome, allergic glomerulonephritis, hyponatremia, hyperkalemia.
From the blood system: aplastic anemia, autoimmune hemolytic anemia, prolonged bleeding time, eosinophilia, leukopenia, thrombocytopenia, decreased hematocrit, thrombocytopenic purpura, agranulocytosis, neutropenia, pancytopenia, bone marrow hypoplasia.
From the nervous system: drowsiness or insomnia, weakness, irritability, agitation, headache, blurred vision, convulsions.
From the sensory organs: tinnitus, otalgia, visual impairment, reversible loss of the ability to distinguish colors, eye irritation.
Allergic reactions: skin rash, skin itching, facial swelling, allergic rhinitis, angioedema, laryngeal edema, Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme, urticaria, bullous pemphigus, photosensitivity, asthma, anaphylaxis.
Others: impaired glucose tolerance in patients with diabetes mellitus, aseptic meningitis.
Expiration date
2 years.
Storage conditions
Store in the original packaging at a temperature not exceeding 25 °C.
Keep out of reach of children.
Packaging
10 tablets in a contour blister pack; 1 or 2 contour blister packs in a pack.
Vacation category
Without a prescription.
Producer
PrJSC "Pharmaceutical Company "Darnitsa".
Location of the manufacturer and its business address
Ukraine, 02093, Kyiv, Boryspilska St., 13.
