Mefenamic acid

Pharmacological properties

mefenamic acid - NSAIDs. 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 that take part in the inflammatory reaction. mefenamic acid stabilizes protein ultrastructures and cell membranes, reduces vascular permeability, disrupts oxidative phosphorylation, 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 center of thermoregulation.

Mefenamic acid stimulates the formation of interferon.

In the mechanism of analgesic action, along with the effect on the central mechanisms of pain sensitivity, an important 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. C_max in the blood is achieved 2-4 hours after administration. Blood levels are proportional to the dose. The equilibrium concentration (20 μg / ml) is determined on the 2nd day of use (1 g 4 times a day). It binds to 90% with blood albumin. It forms metabolites in the liver by oxidation, hydrolysis, glucuronidation. T_½ is 2–4 hours. It is excreted unchanged and in the form of metabolites mainly by the kidneys (67% of the dose) and with feces (20–25%).

Indications

Orvy and the flu. low and medium intensity pain: muscle, joint, traumatic, toothache, headache of various etiologies, postoperative and postpartum pain. primary dysmenorrhea. dysfunctional menorrhagia, including those caused by the presence of intrauterine contraceptives, in the absence of pathology of the pelvic organs. inflammatory diseases of the musculoskeletal system: rheumatoid arthritis, rheumatism, ankylosing spondylitis.

Application

The drug should be used under the supervision of a doctor who determines the dose and duration of treatment. apply inside. the drug should be taken after meals with milk.

Adults and children over the age of 12 are prescribed 250-500 mg 3-4 times a day. According to indications and with good tolerance, the daily dose is increased to a maximum of 3000 mg, after the therapeutic effect is achieved, 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 patients with pain, the course of therapy lasts up to 7 days.

Contraindications

Hypersensitivity to the components of the drug. history of bronchospasm, Quinckes edema, rhinitis, ba or urticaria after the use of acetylsalicylic acid or other NSAIDs. simultaneous administration of specific cog-2 inhibitors. peptic ulcer of the stomach and duodenum, including a history of inflammatory bowel disease, blood diseases of the blood, severe heart failure, severe hepatic or renal impairment, gastrointestinal bleeding or perforation caused by NSAIDs.

Side effects

From the digestive system: 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 blood plasma.

From the cardiovascular system: AH, arrhythmia, rarely - congestive heart failure, peripheral edema, syncope, hypotension, palpitations, shortness of breath.

From the respiratory system: dyspnea, bronchospasm.

From the urinary system: dysuria, cystitis. Impaired renal function, 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.

On the part of the sensory organs: tinnitus, earache, visual impairment, reversible loss of ability to distinguish colors, eye irritation.

Allergic reactions: skin rashes, itching, facial swelling, allergic rhinitis, angioedema, laryngeal edema, Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme, urticaria, bullous pemphigus, photosensitivity, AD, anaphylaxis.

Other: impaired glucose tolerance in patients with diabetes mellitus, aseptic meningitis.

special instructions

The drug is prescribed with caution in patients with acute cardiovascular failure, ag, coronary heart disease. the drug is prescribed with caution in patients with epilepsy.

There are no special recommendations for the use of the drug for moderate impaired liver or kidney function.

NSAIDs should be used with caution in patients with a history of gastrointestinal diseases (ulcerative colitis, Crohns disease), since an exacerbation of the disease is possible.

Elderly patients usually have an increased risk of side effects from the gastrointestinal tract, so treatment should be started with the lowest dose.

Patients with systemic lupus erythematosus and mixed connective tissue diseases have an increased risk of aseptic meningitis. The reception of mefenamic acid must be stopped at the first appearance of a skin rash, damage to the mucous membrane, or with any other manifestation of hypersensitivity.

Taking mefenamic acid can lead to a violation of female fertility and is not recommended for women who are planning a pregnancy.

Use during pregnancy and lactation. Do not use.

Children. The drug is contraindicated in children under the age of 5 years.

The ability to influence the reaction rate when driving vehicles or working with other mechanisms. Caution should be exercised when driving vehicles or working with mechanisms that require increased attention, since sometimes the use of the drug can cause drowsiness, blurred vision, and convulsions.

Interactions

Thiamine, pyridoxine hydrochloride, barbiturates, phenothiazine derivatives, narcotic analgesics, caffeine, diphenhydramine increase the analgesic effect of the drug.

With the combined use of mefenamic acid and methotrexate, the toxic effects of methotrexate are enhanced.

Antihypertensive agents (ACE inhibitors and angiotensin II receptor antagonists): a decrease in the antihypertensive effect.

Diuretics: decrease in diuretic effect. Diuretics can increase the nephrotoxicity of NSAIDs.

Cardiac glycosides: NSAIDs can increase heart failure, reduce glomerular filtration rate and increase the level of cardiac glycosides in blood plasma.

Cyclosporine: increased risk of nephrotoxicity.

Mifepristone: NSAIDs should not be used within 8-12 days after taking mifepristone, NSAIDs can reduce the effect of mifepristone.

Corticosteroids: increased risk of developing 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 developing a nephrotoxic effect.

Tacrolimus: the risk of developing a nephrotoxic effect increases.

Zidovudine: NSAIDs increase the risk of hematologic toxicity. The risk of joint hemorrhage and hematomas in HIV-positive hemophilia patients who are simultaneously receiving treatment with zidovudine increases.

Lithium preparations: reduced lithium excretion and increased risk of lithium toxicity.

Mefenamic acid increases the activity of oral anticoagulants, therefore, with their simultaneous use, the risk of bleeding increases. The simultaneous use of other NSAIDs increases the anti-inflammatory effect and the likelihood of side effects from the gastrointestinal tract.

Overdose

Symptoms: epigastric pain, nausea, vomiting, drowsiness. in severe cases - gastrointestinal bleeding, respiratory depression, ag, twitching of individual muscle groups, coma.

Treatment. There is no specific antidote. Gastric lavage with a suspension of activated carbon. Alkalization of urine, forced diuresis. Symptomatic Therapy Hemosorption and hemodialysis are ineffective due to the strong binding of mefenamic acid to blood proteins.

Storage conditions

In the original packaging at a temperature not exceeding 25 ° C.