Retarpen - Instructions For Use, Price, Analogues, 2.4 Million IU, Reviews

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Retarpen - Instructions For Use, Price, Analogues, 2.4 Million IU, Reviews
Retarpen - Instructions For Use, Price, Analogues, 2.4 Million IU, Reviews

Video: Retarpen - Instructions For Use, Price, Analogues, 2.4 Million IU, Reviews

Video: Retarpen - Instructions For Use, Price, Analogues, 2.4 Million IU, Reviews
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Retarpen: instructions for use and reviews

  1. 1. Release form and composition
  2. 2. Pharmacological properties
  3. 3. Indications for use
  4. 4. Contraindications
  5. 5. Method of application and dosage
  6. 6. Side effects
  7. 7. Overdose
  8. 8. Special instructions
  9. 9. Application during pregnancy and lactation
  10. 10. Use in childhood
  11. 11. In case of impaired renal function
  12. 12. For violations of liver function
  13. 13. Use in the elderly
  14. 14. Drug interactions
  15. 15. Analogs
  16. 16. Terms and conditions of storage
  17. 17. Terms of dispensing from pharmacies
  18. 18. Reviews
  19. 19. Price in pharmacies

Latin name: Retarpen

ATX code: J01CE08

Active ingredient: benzathine benzylpenicillin (Benzathine Benzylpenicillin)

Manufacturer: Sandoz, GmbH (Sandoz, GmbH) (Austria)

Description and photo updated: 2019-27-08

Powder for the preparation of a suspension for intramuscular administration of prolonged action Retarpen
Powder for the preparation of a suspension for intramuscular administration of prolonged action Retarpen

Retarpen is an antibiotic from the group of type G penicillins with prolonged action.

Release form and composition

Dosage form - powder for preparation of suspension for intramuscular administration of prolonged action (1.2 million IU - ~ 1.14 g each in colorless glass vials with a capacity of 5 ml, 1 vial in a cardboard box, 100 vials in a cardboard box (for hospitals); 2, 4 million IU - ~ 2.27 g each in colorless glass vials with a capacity of 15 ml, 1 vial in a cardboard box, 50 vials in a cardboard box (for hospitals). Each pack / box also contains instructions for the use of Retarpen).

The active ingredient is benzathine benzylpenicillin, in 1 bottle - 1.2 million international units (IU) (1.0256 g) or 2.4 million IU (2.0513 g).

Excipients: beckons, simethicone, sodium citrate buffer, povidone.

Pharmacological properties


Benzathine benzylpenicillin - the active ingredient in Retarpen, is a β-lactam antibiotic of type G from the group of penicillins, with a pronounced prolonged action. It exhibits bactericidal activity against susceptible microorganisms by inhibiting the synthesis of mucopeptides of the cell wall.

Microorganisms in relation to which the activity of benzathine benzylpenicillin is manifested: gram-positive causative agents of syphilis and yaws (Treponema spp.); the main causative agents of acute scarlet fever, tonsillitis, rheumatic fever (penicillinase-forming strains of Staphylococcus spp.; Streptococcus spp., including pyogenic and pneumococcal streptococci).

Resistant to the action of benzathine benzylpenicillin: Nocardia asteroides, Enterococcus faecium, Enterobacteriaceae spp., Pseudomonas aeruginosa, Moraxella catarrhalis, Bacteroides spp., Chlamydophila spp., Chlamydophila spp., Chlamydia spp., Chlamydia spp., Chlamydia spp. benzylpenicillin penicillinase.

Acquired resistance to Retarpen is widespread in the following microorganisms: Staphylococcus haemolyticus, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus hominis, Enterococcus faecalis.


After intramuscular injection of benzathine, benzylpenicillin is hydrolyzed very slowly with the release of benzylpenicillin.

The maximum concentration (Cmax) in the blood serum reaches in children 24 hours later, in adults 48 hours after injection. The long half-life (T 1/2) ensures long-term stable presence of Retarpen in the blood. 2 weeks after the injection of Retarpen 2.4 million IU, its serum level is 0.12 μg / ml. 3 weeks after injection of 1.2 million IU in 89–97.4% of cases, the concentration is 0.06 μg / ml (1 IU = 0.6 μg). In the liquid, the diffusion of the drug is complete, in the tissues it is very weak. The substance binds to blood plasma proteins by 40-60%.

The drug is metabolized slightly. It is excreted mainly by the kidneys unchanged. Within eight days, up to 33% of the administered dose is released.

Benzathine benzylpenicillin during lactation penetrates into breast milk, overcomes the placental barrier in low doses.

Pharmacokinetic features in special patient groups:

  • Patients with diabetes mellitus: with intramuscular injection, it is possible to slow down the absorption of the drug;
  • Newborn and premature babies: as a result of functional immaturity of the kidneys / liver, an increase in T 1/2 is possible;
  • Elderly patients: a decrease in the rate of excretion of the drug from the body is likely.

Indications for use

Treatment of infections caused by microorganisms sensitive to benzathine benzylpenicillin, if necessary, long-term exposure to them:

  • Scarlet fever;
  • Acute tonsillitis;
  • Pint;
  • Yaws;
  • Syphilis.

Prevention of infections caused by sensitive microorganisms:

  • Relapses of erysipelas;
  • Repeated attacks after acute rheumatic fever.


  • Lactation period;
  • Hypersensitivity to the components of Retarpen or other beta-lactam antibiotics (cephalosporins or penicillins).


  • Renal and / or hepatic impairment;
  • Diabetes;
  • Dermatomycosis;
  • Pseudomembranous colitis;
  • Tendency to allergic reactions (allergic rashes, bronchial asthma);
  • Pregnancy.

Retarpen, instructions for use: method and dosage

Retarpen is intended for intramuscular administration. A suspension is prepared from the powder, for this, water for injection is injected into the vial: at a dose of 1.2 million IU - 3 ml, at a dose of 2.4 million IU - 5 ml, and then mix thoroughly by rolling the bottle between the palms of the hands, avoiding the formation of abundant foam.

The solution is injected deep into the upper outer quadrant of the gluteus maximus muscle. To exclude the ingress of the needle and, accordingly, the drug into the vessel, aspiration should be performed immediately before administration. In case of aspiration of blood or the appearance of severe pain, the administration of Retarpen should be discontinued.

Recommended dosages for acute tonsillitis, scarlet fever, yaws and pint:

  • Adults and adolescents - 1.2 million IU once;
  • Children weighing 30 kg or more - 1.2 million IU once;
  • Children weighing less than 30 kg - 600 thousand IU once.

Recommended doses for primary and secondary syphilis:

  • Adults and adolescents - 2.4 million IU;
  • Children weighing over 30 kg - 600 thousand - 2.4 million IU.

As a rule, a single administration of Retarpen is sufficient. In case of resumption of clinical and / or laboratory manifestations of the disease, a second course is carried out.

In the late stages of syphilis, including in latent seropositive form, adults and adolescents are prescribed 1 injection of 2.4 million IU once a week for 3 weeks.

In congenital syphilis (without signs of involvement of the central nervous system), 50 thousand IU is prescribed for each kilogram of body weight once a week for 3 weeks.

For the prevention of acute rheumatic fever, erysipelas and post-streptococcal glomerulonephritis, Retarpen is prescribed in the following doses:

  • Adults and adolescents - 1.2 million IU once every 3-4 weeks;
  • Children weighing 30 kg or more - 1.2 million IU once every 3-4 weeks;
  • Children weighing less than 30 kg - 600 thousand IU 1 time in 3-4 weeks.

Recommended duration of treatment:

  • In the absence of heart disease - for at least 5 years or until the age of 21;
  • With transient heart disease - for at least 10 years or until the age of 21;
  • With persistent heart disease - for at least 10 years or until the age of 40 years. In some cases, lifelong preventive therapy may be indicated.

The duration of prophylaxis is set individually.

Special instructions:

  • For patients with renal insufficiency, the dose of Retarpen is calculated taking into account renal function: with creatinine clearance (CC)> 10 ml / minute - 75% of the usual dose, with CC <10 ml / minute - 20-50% (in some cases, it may be necessary to split a single dose. doses for several injections);
  • Elderly patients, before prescribing Retarpen, should assess the state of renal function and, according to the results, adjust the dose, if necessary;
  • With hepatic failure, the metabolism and excretion of penicillins may change, which should be taken into account when choosing a dose.

Side effects

  • Changes in laboratory parameters: often (> 1/100, <1/10) - a positive direct Coombs' reaction, distortion of the results of electrophoresis of blood plasma proteins, an increase in the content of 17-ketosteroids in urine (using the Zimmermann reaction), false positive reactions for determining amino acids in urine (when using the ninhydrin method), false positive reactions to urobilinogen, false positive reactions for determining glucose in urine (when using non-enzymatic methods), false positive reactions for determining protein in urine using the biuret method, the Folin-Chocalteu method or precipitation techniques (when using trichloroacetic, sulfosalicylic acids);
  • Other effects of an immunoallergic nature: acute interstitial nephritis, moderate transient increase in the activity of serum transaminases;
  • Disturbances from the digestive system: often - nausea, diarrhea, vomiting; infrequently (> 1/1000, <1/100) - glossitis, stomatitis; frequency unknown - pseudomembranous colitis;
  • Infections and parasitic infestations: often - candidiasis;
  • Disturbances from the nervous system: rarely (> 1/10 000, <1/1000) - neuropathy;
  • Immune system disorders: rarely - allergic reactions (fever, urticaria, joint pain, angioedema, exfoliative dermatitis, anaphylactic shock with the development of collapse, erythema multiforme, anaphylactoid reactions (purpura, asthma attack, symptoms from the gastrointestinal tract)); very rarely - toxic epidermal necrolysis, malignant exudative erythema; frequency unknown - serum sickness, Jarisch-Herxheimer reaction; in the presence of concomitant dermatomycosis - para-allergic reactions;
  • Disturbances from the blood and lymphatic system: very rarely (<1/10 000) - hemolytic anemia, thrombocytopenia, leukopenia, agranulocytosis;
  • Disorders from the kidneys and urinary tract: rarely - interstitial nephritis, nephropathy;
  • Liver and biliary tract disorders: frequency unknown - cholestasis, hepatitis;
  • Skin and subcutaneous tissue disorders: frequency unknown - pemphigoid;
  • General disorders and reactions at the injection site: the frequency is unknown - local reactions (pain and infiltrates at the injection site), Nicolau syndrome (acute drug embolism of the skin vessels), Hoyne's syndrome (acute penicillin psychotic syndrome); with prolonged therapy - superinfection.


Due to an overdose (use of high doses) of β-lactam antibiotics, including benzathine benzylpenicillin, especially in patients with renal insufficiency, encephalopathy may develop, the main symptoms of which are movement disorders, impaired consciousness, convulsions.

Symptomatic treatment is recommended.

special instructions

Before prescribing Retarpen, a patient's history should be carefully collected for possible hypersensitivity to penicillins and / or other beta-lactam antibiotics.

Given the risk of developing severe allergic, sometimes even fatal reactions, patients should be warned about the need to discontinue Retarpen and immediately consult a doctor if they develop allergy symptoms.

In 5-10% of cases, allergic reactions to penicillin can cross with allergic reactions to cephalosporins, and therefore penicillins are contraindicated in patients with a history of cephalosporin allergy.

Patients with allergic skin rashes and bronchial asthma have an increased risk of developing hypersensitivity reactions, so they should be under medical supervision for at least 30 minutes after injection. In case of an allergic reaction, Retarpen should be canceled and, if necessary, symptomatic and / or anti-shock therapy should be carried out.

When treating syphilis, a Jarisch-Herxheimer reaction (chills, fever, other local and general symptoms) may develop, and patients should be warned about this.

In patients with diabetes mellitus, it is possible to slow down the absorption of the drug into the systemic circulation.

Retarpen should not be administered intravenously, subcutaneously, endolumbar, in the body cavity, as well as in tissues with impaired perfusion.

If the solution accidentally gets under the skin, a painful lump may develop. The application of ice to the injection site can reduce pain.

Accidental intravascular injection may cause transient feelings of anxiety and visual impairment. These symptoms usually resolve within an hour. If symptoms are severe, sedation may be needed.

In case of accidental intra-arterial administration of Retarpen, especially in children, serious complications such as tissue necrosis (gangrene) and arterial thrombosis can occur. Their initial manifestations are pale spots on the skin of the gluteal region. As a result of high pressure at the injection site, a retrograde injection of the drug into the common iliac artery, spinal arteries or aorta is possible.

During treatment, it is necessary to periodically monitor renal function and peripheral blood picture.

In order to prevent damage to the sciatic nerve, the peripheral region of the outer upper quadrant of the buttock for the administration of Retarpen in children and adolescents is used only in exceptional cases (for example, with widespread burns).

Rubbing the buttocks after injection is not recommended.

In case of suspicion of syphilis, dark-field microscopy should be performed before the appointment of Retarpen and then serological studies within 4 months. In congenital syphilis, it is also necessary to examine the cerebrospinal fluid (CSF). If it is not possible to exclude the involvement of the central nervous system in the process (neurosyphilis), other penicillin preparations should be used that better penetrate the CSF.

If persistent severe diarrhea occurs during treatment, pseudomembranous colitis should be suspected (may manifest as watery stools with mucus / blood, tenesmus, diffuse spastic abdominal pain, fever). Since this condition can be life-threatening, Retarpen should be discontinued immediately and appropriate therapy should be prescribed, taking into account the sensitivity of the identified pathogen. Do not use drugs that inhibit intestinal peristalsis.

Patients who adhere to a hypersaline diet should take into account the sodium content in the drug: at a dose of 1.2 million IU - 11 mg (0.48 mmol), at a dose of 2.4 million IU - 22 mg (0.96 mmol).

Due to the risk of fungal infections during treatment, it is advisable to simultaneously use B vitamins and vitamin C. If you suspect the development of a fungal infection, an antifungal drug (for example, levorin or nystatin) is required.

With the use of Retarpen in an insufficient dose, with too early discontinuation of treatment, as well as with long-term therapy, resistant strains of pathogens may appear.

In rare cases, povidone - one of the excipients of Retarpen - can accumulate in the reticuloendothelial system, as a result of which granulomas may develop, from which tumors can form in the future.

Influence on the ability to drive vehicles and complex mechanisms

During treatment, care should be taken when driving a car and performing potentially dangerous types of work.

Application during pregnancy and lactation

Benzathine benzylpenicillin crosses the placental barrier. Despite the fact that no direct / indirect adverse effects on the fetus have been identified in animal experiments, Retarpen can be used during pregnancy only if the intended benefit to the mother significantly exceeds the potential risk to the fetus.

It is not recommended to use Retarpen for the treatment of syphilis in pregnant women.

The drug passes into breast milk in small amounts. There is no evidence of adverse reactions in children whose mothers received Retarpen while breastfed. Since the possibility of a negative effect of the drug on the intestinal microflora of the child is not excluded, breastfeeding is recommended to be interrupted during the use of Retarpen. Breastfeeding can be resumed 24 hours after its cancellation.

Pediatric use

In pediatric practice, Retarpen is used without age restrictions, strictly according to indications in compliance with the dosage regimen.

With impaired renal function

For patients with renal insufficiency, the dose of Retarpen is calculated depending on the degree of impaired renal function (CC indicator):

  • CC> 60 ml / min - dose adjustment is not required;
  • CC 10-60 ml / min - 75% of the calculated dose;
  • CC <10 ml / min (severe renal failure) - 20-50% of the estimated dose, it may need to be divided into several injections.

For violations of liver function

In severe hepatic insufficiency, it is possible to slow down the metabolism and excretion of penicillins.

Use in the elderly

Before starting therapy with Retarpen in elderly patients, renal function should be assessed. If necessary, a dose adjustment corresponding to the condition is carried out.

Drug interactions

Retarpen should not be used concomitantly with bacteriostatic antibiotics (eg chloramphenicol, macrolides, tetracyclines, lincosamides). The combination with other antibiotics is possible only in cases where a synergistic or at least additive effect from the use of a combination of drugs is expected.

Do not inject benzathine benzylpenicillin in the same syringe with other medicines.

With caution Retarpen should be used simultaneously with non-steroidal anti-inflammatory drugs (salicylates, phenylbutazone, indomethacin), probenecid, allopurinol, because possible competitive inhibition of the elimination of drugs from the body.

Retarpen increases the effectiveness of indirect anticoagulants, therefore, when using this combination, the INR (international normalized ratio) should be carefully monitored.

Digoxin increases the risk of developing bradycardia.

Benzathine benzylpenicillin reduces the excretion of methotrexate, as a result of which its toxicity may increase.


Retarpen analogs are: Ampicillin, Amosin, Ospamox, Bitsillin-1, Benzicillin-1, Ospen, Extensillin.

Terms and conditions of storage

Store in a dark place, out of reach of children, at temperatures up to 25 ° C.

Shelf life is 4 years.

The solution prepared from the powder can be stored in the refrigerator for no more than 24 hours.

Terms of dispensing from pharmacies

Dispensed by prescription.

Reviews about Retarpen

Benzathine benzylpenicillin is included in the list of vital and essential drugs. Since it is a very strong antibiotic, patients recommend using the drug exclusively as directed and under the supervision of specialists. In most reviews of Retarpen, patients characterize it as an effective remedy that practically does not cause negative reactions from the body. A single review describes anaphylactic shock after injection, but its causes are not specified. At the same time, the drug coped with the task, the Pseudomonas aeruginosa infection was cured.

According to doctors, Retarpen is a standard drug for the treatment of syphilis, as a rule, it turns out to be effective and allows you to restore the patient's health in most cases without side effects. Retarpen injections are quite painful, therefore, for manipulations, as well as for the correct preparation of the solution, you should contact a medical institution.

The price of Retarpen in pharmacies

The drug is not available commercially. The approximate price of Retarpen 2.4 million IU in online pharmacies is 2500 rubles. for 1 bottle.

Anna Kozlova
Anna Kozlova

Anna Kozlova Medical journalist About the author

Education: Rostov State Medical University, specialty "General Medicine".

Information about the drug is generalized, provided for informational purposes only and does not replace the official instructions. Self-medication is hazardous to health!

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