DIMEDROL (1% injection solution)

Solutio Dimedroli 1% pro injectionibus

International nonproprietary name (INN)

Diphenhydramine.

Composition

1 ml of the solution contains 10 mg of dimedrol (diphenhydramine)

Pharmacotherapeutic group

H-1-antihistamine. Sedative and hypnotic agent.

Pharmacological effect

Pharmacodynamics

Antihistamine, antiallergic, antiemetic, hypnotic, local anesthetic. It blocks histamines Н₁ — receptors and eliminates histamine action via said receptors. It decreases or prevents spasms of smooth muscles due to histamines, impermeability of capillaries, tissue edema, itch and hyperemia. Histamine antagonism is revealed mainly in local vessel reaction under inflammation and allergy against systemic, i.e. decrease of arterial pressure. It produces local anesthesia (oral dosing results in brief anemia of tunica mucosa of mouth), it is spasmolitic, blocks cholinergic receptors of autonomic ganglions (decreases arterial pressure). It blocks Н₃ — histamine receptors of brain and inhibits central cholinergic structures. It is sedative, hypnotic and antiemetic. It is mainly effective in bronchospasm caused by histamine liberators (tubocurarine, morphine, sombrevine), less effective in allergic bronchospasm. In bronchial  asthma it is poor effective and is administered in combination with teophiolline, ephedrine and other broncholotics.

Pharmacokinetics

After i.v., i.m. injection it is widely distributed in organism, passes via blood-brain and placenta. Binding with plasma proteins is 98—99%. It is metabolized in liver. Half-excretion (Т_1/2) is 1—4 h. It is excreted with milk and may provoke sedative effect in infants. It is totally excreted within a day, mainly as benzihydrol, conjugated with glucuronic acid, less excreted unmodified.

Indications for usage

The drug is administered in urticaria, hay fever, vasculitis, vasomotor rhinitis, abgiodema, itching dermatosis, acute iridocyclitis, allergic conjunctivitis and other allergic complications of various drugs, antibiotics inclusive. The drug is also administered in radiation sickness, chorea, sea and air sickness, vomit. 1% dimedrol injection solution may be administered to reduce marked side effect in transfusion of blood and blood-sustaining fluids and other drugs. The drug is well administered as tranquilizer and hypnotic agent either independently or in combination with other hypnotics.

Administration and dosage

The drug is administered i.v. and i.m. S.c. is not administered due to irritation effect. I.m.: 10-50 mg (1-5 ml 1% solution). I.v. by drops 20—50 mg oа dimedrol in 75—100 ml of isotonic solution of sodium chloride.

Max.dose in adults under i.m. injection: 0.05 g (5 ml 1% solution), daily dose — 0.5 g (15 ml 1% solution).

Special indications

Administer with care in patients with hyperthyroidism, high intraocular pressure, cardiovascular diseases, in elderly patients. It is not administered for drivers and in profession with higher reaction ratio. Avoidalcoholundertreatment.

Adverse reaction

Nervous system and sense organs: general weakness, fatigue, sedative effect, reduced attention, vertigo, sleepiness, headache, hypotaxia, anziety, elevated irritation (particularly in children), irritation, nervousness, insomnia, euphoria, mental confusion, tremor, neuritis, convulsions, paresthesia, visual impairment, diplopia, acute labyrinthitis, tinnitus. In patients with local brain damage or epilepsy, it activates (even in low dosage) spastic discharge ECG and may provoke epileptic seizure.

Cardiovascular system and blood: hypotensia, heartbeats, tachycardia, extrasystole, agranulocytosis, thrombocytopenia, hemolytic anemia.

Gastrointestinal organs: dry mouth, brief anemia of tunica mucosa of mouth, anorexia, nausea, epigastric distress, vomit, diarrhea, constipation р.

Urogenital system: frequent and/or heavy urination, retention of urine, e precocious menstruation.

Respiratory system : nasal and throat dryness, stuffiness in nose, coagulation of bronchus secretion, constraint chest and heavy respiration.

Allergic reaction: eruption, urticaria, anaphylactic shock.

Other: hyperidrosis, rigor, photosensitization.

Contraindications

Hypersensitivity, breast feeding, infants (neonates and premature infants), angle-closure glaucoma, prostatic hypertrophy, obstructing gastric and duodena ulcer, pyloroduodenitis obstruction, stenosis of neck of urinary bladder, pregnancy, bronchial asthma а.

Interaction with other drugs

Hypnoticm sedative agents, tranquilizers and alcohol increase (mutually) central nervous system depression. Inhibitors enhance and prolong cholingeric antagonist action.

Overdose

Симптомы: dry mouth, heavy respiration, persistent mydriasis, face redness, depression or excitation (often in children) of СNS, mental confusion, in children – convulsions and fatal outcome.

Treatmentе: symptomatic and sustaining therapy against respiratory and arterial pressure сontrol.

Dosage form

Injection solution 1%. 1 ml per ampul, 10 ampuls per box.