Chemical properties
Vasopressin is described on Wikipedia as an antidiuretic hormone of the hypothalamus that increases the reabsorption of fluid by the kidneys, increasing the concentration of urine and decreasing its volume.
The substance molecule consists of 9 amino acids , in humans the amino acid sequence looks like Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly , the Cys1 and Cys6 are connected by a disulfide bond.
The hormone Vasopressin is synthesized in the body in the large cell neurons of the hypothalamus. The hormone synthesized in the body of the neuron is redirected to the synapses with the help of axons and accumulates in presynaptic vesicles, from where it is excreted into the blood at the moment when the neuron is excited by a nerve impulse.
Most often, the synthetic hormone is produced in the form of solutions for injection or intranasal administration.
Pharmacodynamics and pharmacokinetics
Vasopressin interacts with V and Vi receptors , which are located on vascular smooth muscle cells, thus regulating vasoconstriction. There is an increase in the permeability of the epithelium of the collecting duct for water located in the kidneys and an increase in the process of fluid reabsorption. The substance causes an increase in the volume of blood circulating in the body, hyponatremia and a decrease in osmolarity.
The drug is also capable of increasing the tone of the smooth muscles of internal organs, in particular the gastrointestinal tract, by interacting with V1a receptors . This leads to increased vascular tone and increased peripheral vascular resistance. Blood pressure increases (the medicine narrows the arterioles). The hormone Vasopressin has a hemostatic effect, spasms small vessels and capillaries, affects the von Willebrand blood clotting factor, and stimulates platelet .
The substance also affects the central nervous system, takes part in the regulation of aggression and the process of memorization. Scientists conducted experiments on mice - prairie voles. In the course of these studies, by influencing vasopressin receptors in the brains of animals, mice were able to be made monogamous, faithful to one partner. Thus, it was possible to prove that vasopressin (its AVPR1A) is responsible for the social behavior of animals, finding a partner and the formation of paternal instinct in males.
Synthetic hormone preparations are prescribed parenterally. When administered by injection or intranasally, the half-life of the substance is about 20 minutes. Metabolism of the drug occurs in the tissues of the liver and kidneys, where disulfide bonds are restored and further breakdown of peptides . A small amount of the substance is excreted unchanged in the urine.
Desmopressin
Trade name: Desmopressin International nonproprietary name: Desmopressin. Dosage form: tablets Composition: Tablets 0.1 mg: Active ingredient: Desmopressin acetate - 0.1 mg. Excipients: lactose monohydrate, crospovidone XL, magnesium stearate, ludipress (lactose monohydrate, crospovidone, povidone).
Tablets 0.2 mg: Active ingredient: Desmopressin acetate - 0.2 mg. Excipients: lactose monohydrate, crospovidone XL, magnesium stearate, ludipress (lactose monohydrate, crospovidone, povidone).
Description White round flat tablet with a bevel and a score on one side.
Pharmacotherapeutic group Hormones of the posterior lobe of the pituitary gland. Vasopressin and its analogs.
ATX code: H01BA02.
Pharmacological properties Pharmacodynamics Desmopressin is a structural analogue of the natural hormone arginine-vasopressin, with a pronounced antidiuretic effect. Desmopressin was obtained as a result of changes in the structure of the vasopressin molecule - deamination of L-cysteine and replacement of 8-L-arginine with 8-D-arginine. Desmopressin increases the permeability of the epithelium of the distal convoluted tubules of the nephron to water and increases its reabsorption. Structural changes in combination with a significantly enhanced antidiuretic ability lead to a less pronounced effect of desmopressin on the smooth muscles of blood vessels and internal organs compared to vasopressin, which results in the absence of unwanted spastic side effects. Unlike vasopressin, it acts longer and does not cause an increase in blood pressure. The use of desmopressin in diabetes insipidus of central origin leads to a decrease in the volume of urine excreted and a simultaneous increase in urine osmolarity and a decrease in blood plasma osmolarity. This leads to a decrease in the frequency of urination and a decrease in nocturnal polyuria. The maximum antidiuretic effect when taken orally occurs within 4 to 7 hours. Antidiuretic effect when taken orally at a dose of 0.1 - 0.2 mg - up to 8 hours, at a dose of 0.4 mg - up to 12 hours. Pharmacokinetics Absorption When administered orally, the maximum plasma concentration (Cmax) is achieved within 0.9 hours. Concomitant food intake can reduce the degree of absorption from the gastrointestinal tract (GIT) by 40%. Distribution Volume of distribution (Vd) is 0.2 – 0.3 l/kg. Absorption when taken orally – 5%. Desmopressin does not penetrate the blood-brain barrier. Excretion Excreted by the kidneys. The half-life (T1/2) when taken orally is 1.5 - 2.5 hours.
Side effects
During treatment with the drug, the following may develop:
- headaches, dizziness , nausea;
- pain and inflammation at the injection site;
- abdominal cramps;
- allergic skin rashes, itching, urticaria .
Also rarely, when using large dosages, the following may occur:
- ischemia , ventricular arrhythmia , or intestinal infarction ;
- cardiac arrest, necrosis .
Vazomirin
Particular caution should be exercised when using Vazomirin in patients at risk of intracranial hypertension; patients with fluid and/or electrolyte imbalance and patients with disorders in which overhydration of the body may be dangerous, for example, impaired renal function, heart failure, cystic fibrosis or anesthesia.
Before prescribing Vazomirin, the diagnosis of psychogenic polydipsia and alcoholism should be excluded.
A kidney concentrating ability test in children under 1 year of age should only be performed in a hospital setting.
To prevent fluid retention, caution should be exercised after performing diagnostic tests to detect diabetes insipidus or testing the concentrating ability of the kidneys. Fluid administration should not be forced, either orally or parenterally, and patients should take as much fluid as they require to quench their thirst.
Vazomirin should not be used if there are changes in the mucosa, such as scarring, swelling or other diseases, as this may lead to uneven and unreliable absorption of desmopressin.
In patients with nasal disorders, including colds, there is a risk of unstable and/or reduced effectiveness of the drug. This may also occur in patients engaging in activities that may remove the drug from the nasal cavity before it is absorbed, such as swimming. Vazomirin should not be administered to children who require doses less than 10 mcg of desmopressin (in the form of acetate hydrate).
INFORMATION FOR PATIENTS VAZOMIRIN SPRAY
Desmopressin acetate nasal solution, 10 mcg/dose.
Before using Vazomirin Spray, please read this leaflet carefully and follow these instructions.
1) Blow your nose carefully.
2) Remove the protective cap from the bottle.
3) When using the spray for the first time, prime the pump by pressing the white ring with your index and middle fingers while supporting the bottom of the bottle with your thumb (see Figure 1). Press 4 times in a row or until the spray begins to release evenly. Now the spray is ready for use.
4) While sitting or standing, tilt your head back slightly and carefully insert the nasal applicator into one nostril (see Figure 2).
5) Regardless of the type of spray, press firmly once with your index and middle fingers on the white ring, while supporting the bottom of the bottle with your thumb. Hold your breath while administering the required dose.
6) If more than one dose is necessary, repeat steps 4 and 5 for the second nostril.
When administering an additional dose, alternate nostrils each time.
7) Place a protective cap on the bottle.
Store at room temperature 15-30°C (59-86°F), away from light.
DO NOT STORE THE SPRAY IN THE REFRIGERATOR.
IMPORTANT: Always hold and store the bottle upright.
If the spray has not been used within the last 7 days, it must be refilled. Before inserting the nasal applicator into your nostril, press the white ring several times until the spray is evenly released.
CAREFULLY:
Headache, nausea and mild abdominal cramps are symptoms of overdose. If necessary, consult your doctor to adjust your dose. Elderly patients and children under 12 years of age are advised to limit fluid intake after dinner due to the increased risk of fluid retention in the body.
Vazomirin spray is available in two forms: 2.5 ml (25 doses) and 5.0 ml (50 doses).
Vasopressin, instructions for use (Method and dosage)
The drug is prescribed intramuscularly, intravenously or intranasally .
Vasopressin, instructions for use
glucose solution . The infusion is performed into a central or peripheral vein using a dispenser. 0.3 IU per minute is administered over half an hour, then increased by another 0.3 IU per minute every 30 minutes until the bleeding stops. The maximum dosage is 0.9 IU per minute. After stopping the bleeding, the dosage should be reduced. If any complications or unwanted side effects develop during therapy with the drug, the procedure must be interrupted.
To reduce the risk of adverse reactions, you can simultaneously administer nitroglycerin intravenously to the patient (10 mcg per minute, increasing every 15 minutes by the same amount).
For non- diabetes mellitus, synthetic analogues of Vasopressin are used according to the instructions and recommendations of the attending physician. Most often intranasally.
Desmopressin, 0.2 mg, tablets, 30 pcs.
Monitoring is necessary when treating children and patients at risk of increased intracranial pressure.
To avoid the development of side effects, it is necessary to limit fluid intake to a minimum 1 hour before taking the drug and for 8 hours after taking the drug in patients with primary nocturnal enuresis. Failure to comply with this rule leads to the development of side effects.
Most often, hyponatremia occurs in elderly patients (65 years and older) due to the high risk of side effects (including fluid retention, hyponatremia). Elderly patients with an initially low sodium concentration in the blood plasma and polyuria from 2.8 to 3.0 liters have a high risk of developing side effects. If the decision to treat with desmopressin is made, then before prescription, 3 days after the start of treatment and with each dose increase, it is necessary to determine the concentration of sodium in the blood plasma and monitor the patient's condition.
Desmopressin should not be used in cases where there are other additional causes for fluid retention and electrolyte disturbances.
Prevention of the development of hyponatremia consists of increasing the frequency of determining the concentration of sodium in the blood plasma, especially in cases of simultaneous use with drugs that cause the syndrome of inappropriate secretion of antidiuretic hormone (tricyclic antidepressants, selective serotonin inhibitors, chlorpromazine and carbamazepine) and non-steroidal anti-inflammatory drugs.
If acute urinary incontinence, dysuria and/or nocturia, urinary tract infections occur, if a tumor of the bladder or prostate gland is suspected, if there is polydipsia and decompensated diabetes mellitus, diagnosis and treatment of these conditions and diseases should be carried out before starting treatment with desmopressin.
If systemic infections, fever, or gastroenteritis develop during treatment, the drug should be discontinued.
Impact on the ability to drive vehicles and machinery
There are no data on the possible effect of desmopressin on the ability to drive vehicles and operate machinery. However, during the treatment period, headache and dizziness may occur, so care must be taken when driving vehicles and engaging in other potentially hazardous activities that require increased concentration and speed of psychomotor reactions.
