Magnesium sulfate

General characteristics. Structure:

Active ingredient: 1,25 g of magnesium of sulfate in 5 ml of solution.

Excipient: water for injections.

Pharmacological properties:

Pharmacodynamics. At parenteral administration anticonvulsant, antiarrhytmic, hypotensive, spasmolytic and tokolitichesky action renders sedative, the sleeping pill all-anesthetizing.

Action mechanism. Is a physiological antagonist of calcium, forces out it from places of binding. Participates more than in 300 enzymatic reactions regulating exchange processes, neuromediator processes and neuromuscular transmission. Ions of magnesium act as blockers of potentsialzavisimy calcium channels of a cell membrane. Receipt of calcium ions through a presynaptic membrane is as a result broken that leads to reduction of allocation of acetylcholine and oppression of neuromuscular transmission.

Dozozavisimo oppresses calcium - the mediated allocation of neurotransmitters in a cerebral cortex, causing in process of increase in concentration in plasma sedative in the beginning, then somnolent and anticonvulsant and, at last, the all-anesthetizing effect (anesthesia).

Magnesium sulfate weakens unstriated muscles of internals, a uterus and vessels. Reduces preferential increased arterial pressure and poorly influences normal arterial pressure.

Ions of magnesium have antiarrhytmic effect at the tachyarrhythmias caused by early and late trigger activity due to acceleration of repolarization and shortening of the general duration of action potential (influence on phases [2] and [3] of action potential). On an ECG lengthening of an interval of PQ and shortening of the QRS complex and interval of QT is observed.

Pharmacokinetics. System effects develop in 1 h after intramuscular introduction and almost instantly later intravenous. Duration of preservation of effect makes about 30 min. at introduction to a vein and 3-4 h at intramuscular introduction.

Concentration of ions of magnesium in a blood plasma normal averages 0,84 mmol/l, 25-35% of this quantity are in the state connected with proteins.

Well gets through a placenta and a blood-brain barrier, in milk creates concentration twice the exceeding concentration in plasma.

It is removed with urine (at the same time strengthens a diuresis) by filtering, the speed of renal excretion is proportional to concentration in plasma. 93-99% of magnesium are exposed to the return reabsorption in proximal and distal renal tubules.

Indications to use:

- treatment of deficit of magnesium (hypomagnesiemia) and its prevention at full parenteral food, reception of the combined oral contraceptives, thiazide diuretics, muscle relaxants, an excess long diaforez (perspiration);

- treatment (stopping) of arrhythmias (the supraventricular arrhythmias, arrhythmias caused by reception of antiarrhythmic drugs, glucocorticosteroids, diuretic means, arrhythmias of torsade de pointes, arrhythmia at digitalis intoxication);

- prevention of arrhythmias at a myocardial infarction;

- stopping of hypertensive crisis (including with the wet brain phenomena);

- stopping of a convulsive syndrome at children (including at an acute glomerulonephritis);

- pregnancy not incubation, late toxicoses of pregnancy (gestoses);

- preeclampsia and eclampsia;

- poisoning with salts of heavy metals, arsenic, tetraethyllead, soluble salts of barium (antidote).

Route of administration and doses:

The drug is administered intramusculary or intravenously slowly (the first 3 ml - within 3 min.). At intravenous administration the patient has to be in a prone position.

The adult appoint 1,25 - 5,0 g (5-20 ml of 25% of solution) 1-2 times a day. At poisonings as an antidote intravenously enter 0,25 - 1,0 g (5 - 10 ml in the form of 5-10% of solution).

When stopping arrhythmias enter intravenously slowly 2,0 - 4,0 (8-16 ml of 25% of solution) within 1-2 min., then pass to the supporting infusional introduction within 2 hours. For this purpose 10 ml of 25% of solution dissolve in 200 ml 5% of glucose or potassium - the polarizing mix and enter with a speed of 3-20 mg/min. (5-30 caps/min.).

At treatment of late toxicosis, a preeclampsia and eclampsia use administration of magnesium of sulfate according to Richard's scheme: originally 4,0 g (16 ml of 25% of solution) intravenously slowly within 3-4 min., in 4 hours repeat intravenous administration in the same dose and in addition enter intramusculary 5,0 g (20 ml of 25% of solution). In the subsequent each 4 hours repeat intramuscular administration of magnesium of sulfate in a dose of 4,0 - 5,0 (16 - 20 ml of 25% of solution). Instead of Richard's scheme perhaps intravenous drop administration of 5,0 g of magnesium of sulfate (20 ml of 25% of solution) in cultivation on 400 ml of 0,9% of solution of sodium of chloride or 5% of glucose with a speed of 9 - 25 mg/min. (15 - 40 caps/min.).

To children for stopping of spasms appoint at the rate of 20 - 40 mg/kg (0,08 - 0,16 ml/kg of 25% of solution) intramusculary.

Features of use:

Pregnancy and lactation. At magnesium pregnancy sulfate is applied with care, only in cases when the expected therapeutic effect exceeds potential risk for a fruit. In need of use in the period of a lactation it is necessary to stop breastfeeding.

Use in pediatrics. Sulfate magnesium use according to indications for children of the first year of life under control of tendon jerks and concentration of magnesium in plasma is possible.

At prolonged use control of indicators of the central hemodynamics, monitoring of the ABP, action of the heart, tendon jerks, respiration rates and functions of kidneys is required.

In need of simultaneous administration of drugs of calcium, they should be entered into different veins from magnesium sulfate.

At laboratory control of level of magnesium in plasma, it must be kept in mind that normal indicators of level of magnesium in plasma do not exclude its deficit in fabrics since concentration of magnesium in plasma and its level in intercellular liquid are not always interconnected.

Side effects:

- bradycardia, conductivity disturbance;

- feeling of inflows of heat, perspiration;

- hypotension, weakness, headache;

- deep sedation, oppression of tendon jerks;

- asthma;

- nausea, vomiting;

- polyuria.

Interaction with other medicines:

At combined use strengthens action of other means oppressing a nervous system (alcohol, psychotropic, somnolent, protivoparkinsonichesky, anticonvulsants). At combined use with barbiturates, narcotic analgetics, antihypertensives the probability of oppression of a respiratory center amplifies.

Cardiac glycosides strengthen risk of development of disturbances of conductivity and AV blockade at combined use from magnesium sulfate.

Muscle relaxants and nifedipine increase ability of magnesium of sulfate to cause neuromuscular blockade.

Intravenous administration of salts of calcium weakens effect of magnesium of sulfate.

Pharmaceutical it is incompatible (forms a deposit) with calcium drugs, alcohol (in high concentration), carbonates, bicarbonates and a phosphatatami of alkaline metals, salts of arsenic acid, barium, strontium, clindamycin phosphate, a hydrocortisone succinate, polymyxin B sulfate, Procainum, salicylates and tartrates.

Contraindications:

- myasthenia;

- the expressed bradycardia or AV blockade;

- the expressed renal failures (clearance of creatinine less than 20 ml/min.);

- hypersensitivity and gipermagniyemiya.

Overdose:

Classical precursory symptom of intoxication at increase in level of magnesium in plasma to 2,0-3,5 mmol/l is disappearance of a knee jerk. In the subsequent at achievement of level of magnesium in plasma of 3,5-5,0 mmol/l sharp lengthening of an interval of PQ and expansion of the QRS complex on an ECG, bradycardia appears. At the level of magnesium of 4-5 mmol/l deep tendon jerks are lost, there is nausea, vomiting, sharp lowering of arterial pressure, a hyperhidrosis, a diplopia, there is a greased speech. At the level of magnesium of 5,0-7,5 mmol/l there is respiratory depression and disturbance of conductivity of heart. At the level of magnesium of 12,5 mmol/l the cardiac standstill and deep oppression of TsNS is observed.

Help measures. Introduction of a specific antidote - calcium salts (Calcii chloridum or a gluconate) intravenously at the rate of 100-200 mg of the ionized calcium within 5-10 min., if necessary repeatedly. In cases of heavy intoxication - apply IVL, peritoneal dialysis or a hemodialysis. Carry out symptomatic therapy (stimulators of TsNS, means corrective function of cardiovascular system).

Storage conditions:

At a temperature not above 25 °C. To store in the place, unavailable to children. A period of validity - 3 years. Medicine cannot be used after the term specified on packaging.

Issue conditions:

According to the recipe

Packaging:

On 5 ml of solution for injections in an ampoule, 10 ampoules in a box from a cardboard; on 5 ml of solution for injections in an ampoule, on 1 or 2 blister packagings on 5 ampoules in a pack from a cardboard.