Gastrozepin® [Pirenzepine]

Pharmacological properties

Pirenzepine is a selective blocker of m1 cholinergic receptors of the lining and main cells of the gastric mucosa, inhibits the production of hydrochloric acid and increases the pH of the stomach. in therapeutic doses does not penetrate the GEB.

Pharmacokinetics Pirenzepine is not fully absorbed in the digestive tract. C_max in blood plasma is determined 1-3 hours after oral administration and 20-30 minutes after i / m injection. After oral administration, the average bioavailability is 10–20%.

Concomitant use with or before meals reduces AUC by 30%. Only 12% of pirenzepine binds to plasma proteins. It penetrates poorly through the placental barrier and the BBB, in minimal amounts it is excreted into breast milk.

After ingestion, it is almost completely eliminated with feces, with parenteral administration, it is equally with urine and feces. The total plasma clearance is about 250 ml / min. Renal clearance is about half of this value, which is approximately equivalent to the level of glomerular filtration. The drug is characterized by prolonged T_½ (10-12 hours), which explains its long-term therapeutic effect.

The pharmacokinetics of the drug in renal or hepatic insufficiency does not significantly change. The apparent volume of distribution is on average 14 liters, which corresponds to the approximate volume of the extracellular space of a person.

Indications

Tablets. acute and chronic forms of stomach ulcers and duodenal ulcers.

Rr for injections. Prevention and treatment of ulcers caused by stress; bleeding erosion or ulcers of the upper gastrointestinal tract, the initial treatment of severe acute and chronic forms of stomach ulcers and duodenal ulcers.

Application

Tablets are prescribed orally at a dose of 50-150 mg / day in several doses. as a rule, 50 mg 2 times a day is recommended. very rarely, in the first 2-3 days of treatment, it becomes necessary to take an additional dose in the afternoon.

Take morning and evening 30 minutes before meals with a small amount of liquid. Continuous oral therapy should be carried out (even with rapid subjective improvement) for at least 4-6 weeks without reducing the dose of the drug.

Injection solution is usually administered in / m or iv in 2 ml (contents of 1 ampoule) with an interval of 12 hours. For the prevention and treatment of stress ulcers of the upper gastrointestinal tract, it is recommended to introduce 2 ml of solution 3 times a day at intervals 8 h

Parenteral therapy with Gastrozepine should be carried out until clinical improvement (usually within 2-3 days), after which they switch to taking the oral form of the drug.

Note. In / in the introduction of the drug is carried out bolus slowly (at least 3 minutes) or, preferably, by infusion (in / in drip). For iv infusion, the Gastrozepin injection solution can be diluted in isotonic sodium chloride solution, Ringers solution, 5% levulose solution or 5% glucose solution.

Contraindications

Hypersensitivity to the drug, paralytic bowel obstruction, childhood. for the drug in the form of injections, the period of pregnancy and lactation.

In patients with rare galactose intolerance, Lapp lactose deficiency or impaired absorption of glucose and galactose, the tablet should not be used.

Side effects

There is a feeling of dry mouth, disturbances of accommodation, tachycardia, diarrhea, constipation, urinary retention, headache, hypersensitivity, anaphylactic reactions, rash.

special instructions

The drug should be prescribed with caution in glaucoma and prostatic hypertrophy, tachycardia.

Gastrozepin tablets contain 833.64 mg of lactose at each maximum recommended daily dose.

IV injections should always be carried out slowly due to the risk of thrombophlebitis due to the content of 39.2% propylene glycol; patients with unstable blood circulation due to the high initial level of blood pressure need constant monitoring.

During pregnancy and breastfeeding. Information on the use of the drug during pregnancy is limited. It is established that pirenzepine is excreted in breast milk in an insignificant amount. As a result of this, an anticholinergic effect is possible in a breast-fed baby.Studies on the effects on fertility and reproductive function have not been conducted. Avoid the use of the drug during pregnancy and lactation.

Children. Do not use.

Influence on the ability to drive vehicles and work with other mechanisms. Studies on the effect on the reaction rate when driving vehicles and working with other mechanisms have not been conducted. But patients should be warned about the possible occurrence of such undesirable reactions as a violation of accommodation. Therefore, the drug must be used with caution while driving and when working with other mechanisms. If the patient experiences accommodation disturbances, he should avoid potentially dangerous activities.

Interactions

The simultaneous use of Gastrozepin and h2 receptor blockers leads to marked inhibition of hydrochloric acid secretion. the effect of anti-inflammatory drugs does not change with simultaneous use with Gastrozepin. on the other hand, the susceptibility of the digestive tract to these products is improved.

Overdose

Symptoms: to date, there have been no reports of cases of overdose in humans. however, when the drug is administered in high doses, anticholinergic effects are possible: dryness, moisture and hyperemia of the skin, a feeling of dryness of the oral mucosa, mydriasis, delirium, tachycardia, intestinal obstruction, urinary retention, reflex myoclonic movements, choreoathetosis.

Treatment: hemodialysis, hemoperfusion, peritoneal dialysis and repeated doses of activated charcoal are ineffective for excretion of anticholinergic agents.

In case of severe intoxication (hyperthermia, severe delirium or tachycardia), iv administration of physostigmine in low doses is indicated. In the case of the development of acute glaucoma, it is necessary to prescribe miotic agents and immediately consult a specialist.

Storage conditions

Injection solution - in a dry, dark place at a temperature of no higher than 25 ° C; tablets - at a temperature not exceeding 30 ° C.