An uncharacteristic level of hemoglobin concentration is one of the signs of anemia. In fact, this is not a diagnosis yet, but only a symptom that serves as a hallmark of many diseases. The progress of such a pathology may indicate a primary lesion of the blood system.
The stimulator of erythropoiesis, known under the international non-proprietary name as “Epoetin alfa”, the instructions for use are positioned as a highly effective reagent, the pharmacological properties of which are aimed at the treatment and prevention of anemia of various etiologies. Properly selected dosage not only helps to stabilize the component structure of the blood, but also positively affects the work of the heart muscle.
Release form and chemical composition
The drug product is supplied to pharmacies in the form of:
- sterile disposable syringes with a preset dose (the design provides for additional needle protection);
- solution in bottles.
The role of the auxiliary ingredient is given to:
- injection water;
- sodium chloride and dihydrate hydrogen phosphate;
- polysorbate-80.
The biological activity of the substance in the bottles may be different. Most often, this is a thousand or two thousand international units for every 0.5 ml of liquid. However, other forms of the reagent are also on sale, including Epoetin Alfa 10,000 units / 1 ml.
The mechanism of pharmacological action
The biological and immunological properties of the synthesized preparation are absolutely identical to natural erythropoietin. Therefore, the medication very effectively inhibits the symptoms of anemia and adjusts the composition of the blood as a typical glycoprotein. I must say that Epoetin Alpha is primarily focused on increasing hematocrit and normalizing hemoglobin levels. Its “cardiac function”, as well as the tendency of components to improve blood flow in tissues, is less pronounced.
Half-life:
- with intravenous injection - four hours;
- with subcutaneous injection - about a day.
The maximum plasma concentration of the reagent should be expected after 12-18 hours.
Pharmacokinetic nuances
In the course of studies, it was found that the described drug induces the formation of antibodies in the "latent" mode, and its pharmacological significance in bone marrow fibrosis is close to zero. The protein fraction of the Epoetin Alpha drug contains about 165 amino acids (58% of the total molecular weight), and this is reflected in the degree and quality of the effect of the components on the division / differentiation of progenitor cells.
Repeated intravenous administration (provided there are no renal pathologies) does not lead to the accumulation of the active substance; in children under 12 years of age, a prolongation of the T1 / 2 period to 6 hours is likely.
Indications for appointment
"Epoetin alpha" is recommended for use if:
- anemia is diagnosed as a hematopoietic function disorder that accompanies cancer (non-myeloid tumors occur);
- the patient feels the need for regular hemo- or peritoneal dialysis ;
- the question is about conducting a complex surgical operation using allogeneic blood transfusions;
- the patient is HIV-infected and receives zidovudine-based therapy;
- effective prevention is required.
Optimal dosage
For the preparation "Epoetin alpha", the formula for individual selection of the daily dose is valid. However, the general recommendations of the manufacturer are reduced to such provisions and norms:
- at the start of the correction phase: fifty units of action (IU) per kilogram of body weight, but not more than three injections / infusions per week;
- in the absence of visible shifts: 75 U / kg with the same interval, but not earlier than a month after the start of treatment;
- in exceptional situations: 100-200 IU / kg, strictly adhering to the indicated injection schedule (increase step - 25 IU / month);
- maintenance therapy: the dose is prescribed based on the calculation of the hematocrit in the range of 30-35 vol. %
As practice shows, the “standard” is most often taken as a one-time rate of 30-100 IU / kg, which is usually taken at the end of the dialysis procedure. The optimal duration of iv infusion is one to two minutes; with the subcutaneous mechanism of delivery of the active substance, they are guided by the same rules.
Classification of probable side effects
On the scenarios of the atypical reaction of the body to the presence of the components of the drug “Epoetin alpha”, the instructions for use report the following:
- visualization of the symptoms inherent in influenza viruses is possible - severe dizziness, depression, weakness, fever, acute pain in the joints / muscles;
- imbalances in the work of the heart and blood lines are permissible - a sharp increase in blood pressure, malignant hypertension;
- you can not ignore the risk of thrombocytosis (this disease, although it makes itself felt extremely rarely, is fraught with serious complications);
- The reagent can influence the urinary system by changing the amount of potassium and phosphates in the body (an increase in the level of creatinine in blood plasma is not excluded).
On the skin, irritations provoked by the administration of the drug “Epoetin alpha” are also sometimes noticeable. The instruction, in particular, talks about rashes, eczema, angioedema. And what's interesting: with subcutaneous injections, the percentage of severity is much higher: about a thousand average cases account for about 4 episodes (with IV infusions - only 1.6).
There is no reliable information about the immune changes that would be caused by the indicated substance (only the previously mentioned ability of the drug to induce the formation of antibodies deserves attention).
Contraindications declared by the manufacturer
Judging by the information provided in the official manual, “Epoetin alpha” (analogues, such as “Binokrit” and “Eralfon”, in this regard are as close as possible to the original) should not be used if:
- diagnosed with uncontrolled arterial hypertension;
- the patient has hypersensitivity to the ingredients;
- preliminary analysis showed the presence of critical pathology of the blood lines;
- the patient suffered a heart attack (we are talking about the foreseeable past);
- there is reason to believe that normal blood circulation in the parts of the brain is impaired.
In other words, the start of therapy should be preceded by a medical examination.
special instructions
“Epoetin alfa” (the trade name of a structurally identical preparation may be different - for example, its analogues may be offered as a substitute: “Aeropin”, “Repoetin-SP”, “Epocomb”, “Eprex”, etc.) should be used with increased caution in relation to people suffering from intermittent / chronic disorders of the peripheral musculature. This rule is especially relevant if in the anamnesis, episodes of convulsive reactions have already been recorded as the body's response to the intake of certain drugs.
Watch out for gout as well. First of all, the emphasis should be placed on issues related to blood pressure and the occurrence of a headache (antihypertensive drugs - one of the options for medical course adjustment). However, it is equally important to assess the true state of the iron depot (even before regular injections). When the implementation of adequate measures is not reflected in blood pressure, the reception of the described pharmacological product is stopped.
It must be remembered that renal failure, oncology and HIV infection are included in the list of diseases, during the course of which, against the background of an increase in the concentration of hematocrit, a characteristic decrease in the level of ferritin in the blood plasma occurs. To level the imbalances, they resort to substitution therapy involving Fe-containing reagents.
It is advisable to take hemoglobin samples 1 time every 7 days. Also, during the starting two months, regular monitoring of platelet count is required. And 5-10 days before surgery, substances with antithrombotic properties are injected into the patient’s medical record.
The manufacturer does not exclude that the components of the drug are able to influence certain types of tumors, therefore, patient monitoring should not stop even after the end of the active phase of treatment.
What to do in case of overdose?
“Epoetin alpha” (synonyms, drugs, by the way, behave in a similar way) in case of overdose acts according to the algorithms laid down in the chemical formula of recombinant erythropoietin, that is, it provokes polycythemia and fluctuations in the hematocrit level. Due to the lack of classic antidotes, no special measures are taken to deactivate the ingredients - the next medication is simply canceled.
Intentional bloodletting is applicable in emergency cases, when the hemoglobin prohibitive indicator signals a real threat to life.
Drug Interactions
When conducting multi-stage complex therapy, it is extremely important to understand the principles of the “pharmacological behavior” of the Epoetin Alpha reagent (the release form, as mentioned above, may be different, but the mechanism of the biochemical reaction does not change from this).
So, in particular, parallel administration with blood preparations has a positive effect on the health dynamics. But you need to remember that dilution of one solution with another is unacceptable. The medicinal “union” with cyclosporine is fraught with a decrease in the concentration of the latter (the optimal volume ratio of doses is determined empirically).
Reviews and comments
An analysis of the opinions expressed shows that the greatest number of questions arises when it comes to affordable options for solving the same problem. For example, few patients are guided by the differences that exist between pharmacological products such as Epoetin Alpha and Epoetin Beta.
What is the difference - it is easy to understand if you pay attention to the comments of doctors. The fact is that the structural model of natural erythropoietin is represented by two chains, and both have the desired effect on the blood system. Manufacturers of drugs, due to differences in technology, synthesize either an alpha fragment or beta.
As for the reviews about the drug itself, many of those who had to try it on themselves indicate that the tool is quite effective, and in some special cases completely indispensable for certain categories of patients.