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Dexdor
Dexdor or dexmedetomidine is a highly selective α2 receptor agonist, which is used to provide moderate and mild sedation in adult ICU patients.
Pharmacodynamics
Dexmedetomidine has a wide variety of pharmacological effects, and is also a selective α 2 -adrenoreceptor agonist. Since the drug reduces the release rate from the nerve endings of norepinephrine, it has a powerful sympatholytic effect on the body. The sedative effect appears due to a decrease in the excitability of the blue spot, which is the basis of the NA nucleus (located in the brain stem). Influencing this area, Dexdor and has a sedative effect (similar to natural sleep) - the drug causes sedation, but the patient at the same time is in an active waking state.
Dexmedetomidine acts as an anesthetic, and also has a mild analgesic effect for chronic pain in the lower back. The strength of the effect will depend on the dosage. If the infusion rate is low, the central effect will prevail, as a result of which the blood pressure and the heart rate will decrease. Higher dosages have peripheral, narrowing vessels, action, increasing blood pressure. In this case, the severity of the bradycardic effect is enhanced. Dexmedetomidine almost does not suppress the functioning of the respiratory system.
Pharmacokinetics
Dexmedetomidine binds to blood plasma proteins by 94%. The constant limit of accumulation of the substance is 0.85-85 ng / ml. This component binds to α-1-acid glycoprotein, as well as serum albumin. Metabolized mainly in the liver.
After the introduction of radio-labeled dexmedetomidine intravenously into the body after 9 days, approximately 95% of the labeled agent was detected in the urine, and 4% in the stool. In urine, the main metabolic products are 2 isomeric N-glucuronides, which together constitute approximately 34% of the total dose, and in addition N-methylated O-glucuronide, part of which is 14.51% of the dose. The proportion of secondary metabolites (this is a carboxylic acid, and in addition tri-hydroxy, as well as O-glucuronide substances) is separately equal to 1.11-7.66%. Less than 1% of the unchanged substance remained in the urine. Approximately 28% of all metabolites found in urine are unidentified polar metabolic products.
Side effects of the dexdor
Among the most common side effects of taking dexmedetomidine are: AH (15% of patients), lowering blood pressure (25%), and bradycardia (13%). Among other adverse reactions:
- system of blood and metabolism: most often hypo- and hyperglycemia; In rare cases, metabolic acidosis or hypoalbuminemia is observed;
- mental disorders: manic and convulsive conditions; in rare cases - hallucinations;
- cardiovascular system: most often myocardial infarction, ischemic heart disease or tachycardia; less frequent development of ABB 1 degree, as well as lower MOS;
- respiratory organs: dyspnoea is observed occasionally;
- organs of the digestive tract: mainly vomiting with nausea, a feeling of dryness in the oral cavity; rarely - flatulence;
- general disorders, as well as local reactions: mainly hyperthermia or withdrawal syndrome; thirst and lack of therapeutic effect of the drug can rarely be observed.
Dosing and administration
Adult patients who have undergone intubation and are in a state of sedation are allowed to transfer to the reception of Dexdor. The initial infusion rate should be 0.7 μg / kg / h, and then it is allowed to gradually adjust (the maximum possible dosage is 0.2-1.4 μg / kg / h) to obtain the necessary sedation index. At the initial stage, it is advisable to reduce the infusion at a low rate. It should be noted that dexmedetomidine is a potent substance, so for him the infusion rate in time is 1 hour.
Often in a concentrated shock dose the patient does not need. Patients who need to be injected into the sedation sooner, you can first introduce a loading infusion in the volume of 0.5-1 μg / kg of weight for 20 minutes. In this case, the initial infusion volume will be 1.5-3 μg / kg / h for 20 minutes. After the introduction of loading infusion, the subsequent rate will be 0.4 μg / kg / h. This indicator can be further adjusted.
Overdose
The highest infusion rate of dexmedetomidine in an overdose was 60 μg / kg / h for 36 min, and 30 μg / kg / h for 15 min (respectively, for a child of 20 months and for an adult). Most often in the case of an overdose, such reactions as a decrease in blood pressure, bradycardia, increased sedation, a feeling of drowsiness, as well as cardiac arrest were observed.
Interactions with other drugs
The use of Dexdorum in combination with sedatives and hypnotics, as well as anesthetics and opioids can cause the potentiation of the effect of their effects. Due to the research, it was possible to identify the potentiation of the effect in the situation of concomitant reception with the substances sevoflurane, propofol, isoflurane, midazolam, and also alfentanil.
There were no traces of pharmacokinetic interaction between these substances (except sevoflurane) and Dexdor. But, as there is the possibility of pharmacodynamic interaction in the case of combining these drugs, the dosage of Dexdor or a sedative combined with it, anesthetic, opioid or hypnotic may require a reduction.
When combined with Dekstdorom drugs that cause a bradycardic and hypotensive effect, these effects can be intensified. But, it should be noted that in the study of the interaction of this drug with esmolol, the additional effect was moderate.