Methyldopa

Chemical name

3-Гидрокси-альфа-метил -L-тирозин

Gross

C10-H13-N-O4

Characteristics

White or jeltovato-bely powder odourless. Rat in the water.

Of drugs

The drugs-gipotenzivne. Does альфа_2-адренорецепто��ы presinapticescoy neuronal membranes vazomotonego the oblong brain and inhibits sympathetic impulsaciu receptacle. Once inside bioavailability is about 50%. Biotransformation begins in the gastrointestinal mucosa (formed ortosulfirovanne derivatives). Penetrates into central nervous system, where about 10% of the dose and decarbauxiliruetsa бета-гидроксилируетс�� metildofamin in, and then in metilnorarenalin. The livers are compared with sulphates. Relationship with blood plasma proteins less than 20% (30-40% for kongugatov). Time to C_max 2-6 hour T_1/2-2 hours; Excreted largely unchanged in the form as well as in o-sulfatnykh kongugatov; Cl kidney is about 130 mL / min; Excretion curve is bieksponencialny nature - I phase in persons with normal kidney function is 100-120 min (in the same period excreted 90%); 2nd phase of the ingestion of about 2 hours; in the long-term use koumouliruet. In severe renal failure is slowing down (in the first phase excreted only 50%), with Hepatic - биотрансформация.Сни��ает CSO is ortostaticescuu tissues, moderately suppresses the activity of plasma renin and reduces the concentration of fabrics serotonin, dopamine, epinephrine. Sale of blood and blood fat are not significantly altered, and plasma increases. With long-term use can cause regression isolationist left heart to the increase of collagen in miocarde. After the first dose, in some cases, a short-term hypertension. During physical activity gipotenzivny effect less pronounced. Wrinkles sinusovy rhythm; Delay excretion of sodium and water, increases baroretseptorov activity, which may induce the development of the refrakternosti long (1-1.5 months) treatment. Characteristic syndrome "lifting." It sedatia, decreasing in 2-3 weeks after the start of treatment. Once inside minimize the AD is four to six hours and lasts for 1-2 days; In the first few days of treatment gipotenzivny effect gradually increasing. The on / in a drop AD is 2-3 h, peak effect, through May 3 h period of 6-10 hours

Indications

Arterial hypertension.

Contraindications

Hepatitis, cirrhosis of liver, renal and hepatic failure, feohromotsytoma, depressive condition, acute myocardial infarction, cerebrovascular disease, severe disease, haemolytic anaemia, kollagenoz, parkinsonism.

Side-Effects

Weakness, fatigue, drowsiness, dizziness, headache (arise in the early stages of treatment and usually disappear soon), artralgia, mialgia, er syndrome, red top half of the body, dry mouth, inflammation of salivary glands, glossalgia, vomiting, nausea, constipation, colitis, the liver, pancreatitis, aetiology, oedema, ortostatical gipotenzia, stenocardia, cardiac failure, parkinsonism, the paralysis of the facial nerve, horeoatetoidnye spontaneous movement parestesia, impotence, reduced libido, ginekomastia, giperprolaktinemia, haemolytic anaemia, thrombocytopenia, allergic reactions.

Specific guidance

It may mask the increases in infectious diseases. The drug and its metabolites react with the standard chemicals used for the determination of catecholamines. Changes tests for stays acid RNA creatinine and some other substances. Urine patients in the treatment of standing is a dark colour.

Patient interaction

Beta-blokatora increased risk of developing hypertension as (at the expense of альфа-метилнорадрена��ина at nezablokirovanne �льфа-адренорецепторы �osudov and hearts) and Orthostatic Hypotension. Antigipertenzivny effect reduce adrenomimetiki, MAO inhibitors, Tricyclic antidepressants and NPVS. Incompatible with rezerpinom, with a caution to appoint neiroleptikami, hinidine, prokainamidom, diacarbom. In the application with levodopa is mutual reinforcement effects (Braking decarboxylation), with galoperidolom-dementia (the probability), with digoxinom (older), the weakness syndrome sinusnogo hub. Increases toxicity lithium gepatotoksicnosti oral contraceptives.

Overdosing

There is a severe gipotenziei, bradikardiei, inhibition, tremorom, sonlivostew, nausea, vomiting, diarrhea, flatulence, atonia bowel. The curative measures to flush the stomach, big diurez, dialysis may simpatomimetikov appointment. Control of the heart rhythm, BCC, electro balance function of the kidneys and central nervous system.

Precautions

In order to prevent the development of the syndrome that gradually reduced doses. Do not assign patients in the management of road or work requiring greater attention. At the time of treatment precluded admission of alcohol. Patients with impaired kidneys, it is necessary to reduce single dose. The therapy required monitoring liver function and the picture peripheral blood; If you have a direct positive test Kumbsa and hemolytic anemia requires removal treatment.

Dosing and Administration

Inside, in / 386/1989 The ingestion initial dose-250 mg 2-3 times a day (first reception in the afternoon, at night), every 2 days increased by 250 mg maximum daily dose of 3 g (when combined with other hypotensive drugs is not more than 500 mg / day). In achieving effective dose to reduce support for the 250 mg every 2 days. For children initial dose of 10 mg / kg per day for the reception 2-3 with a maximum daily dose of 65 mg / kg / sut. For older persons, the initial dose-125 mg 1-2 times a day with a maximum daily dose of 2 g 2 admission. B / drip in over 30-60 min, 250-500 mg per 100 ml of 5% glucose.

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