Penicillin G Benzathine - Indications, Side Effects, and Pharmacological Aspects

Overview:

Penicillin G benzathine is a prescription antibiotic used to treat certain bacterial illnesses, such as syphilis, upper respiratory tract infections, and skin infections like pinta (a skin condition caused by the Treponema carateum bacteria), yaws (a bacterial infection that damages cartilage, skin, and bones), and bejel (a rare infectious disease brought on by Treponema pallidum endemicum, a spiral-shaped bacterium also known as spirochete). It is also authorized to prevent other bacterial illnesses, such as rheumatic fever and associated ailments. The United States Food and Drug Administration approved the drug in 1945.

Drug Group:

Penicillin G benzathine belongs to the drug group of beta-lactam antimicrobials.

Available Doses and Dosage Forms:

• A single dosage of 2,400,000 units of Penicillin G benzathine is advised for the treatment of primary, secondary, and latent syphilis.

• A dosage of 2,400,000 units should be given three times at seven-day intervals for late syphilis (including tertiary and neurosyphilis).

• The dosage changes according to age in cases of congenital syphilis:

  • A dose of 50,000 units per kilogram of body weight is administered to newborns under two years old.

  • Children between the ages of two and 12 should have their dosage changed according to the adult dosage regimen.

For Patients:

What Is Syphilis?

Treponema pallidum is the bacteria that causes syphilis, a sexually transmitted infection (STI). Primary, secondary, latent, and tertiary stages advance. Different indications and symptoms may appear at each level. Inadequate management of syphilis can result in serious health issues such as blindness, damage to the heart, and neurosyphilis, which affects the neurological system. Antibiotic drugs, usually Penicillin, can effectively treat syphilis and stop it from progressing to more severe stages.

How Does Penicillin G Benzathine Work?

Penicillin G benzathine is a beta-lactam antibiotic known for its bactericidal (kills bacteria) characteristics. The mechanism by which beta-lactam antibiotics work against bacteria is by preventing the peptidoglycan in their cell walls from being biosynthesized, especially while the bacteria are actively multiplying. Penicillin-binding proteins (PBPs), or bacterial peptidoglycan transpeptidase, are vital enzymes forming cell walls. This suppression takes place by targeting PBPs. Consequently, the bacteria cannot form a viable cell wall, which causes cell lysis and, eventually, bacterial death.

What Are the Things to Inform the Doctor Before Taking Penicillin G Benzathine?

• Patients should disclose any known allergies to their doctor and pharmacist before receiving a Penicillin G benzathine injection, especially if they are allergic to Penicillin, tetracyclines, cephalosporins, or other drugs.

• Any allergies they may have to the ingredients present in the injection should also be disclosed.

• All prescription and over-the-counter drugs, vitamins, supplements, and herbal remedies consumed, including Probenecid, should be provided to the doctor as they might have to regularly check for side effects or change the dosage of medications.

• Any history of renal (kidney) disease, allergies, allergic rhinitis or hay fever (watery and itchy eyes), asthma (a disorder where breathing becomes challenging due to inflammation, narrowing, swelling, and increased mucus production in the airways), or hives (skin rash) should also be disclosed by the individual. They should inform their doctor if they are nursing a baby, planning a pregnancy, or both. It is recommended to seek medical attention right once pregnancy develops while receiving Penicillin G benzathine injection.

How Is Penicillin G Benzathine Administered?

Benzathine Penicillin is available as an injectable suspension for intramuscular usage; it is not recommended for subcutaneous, intravenous, or intra-arterial injection. An injection of the drug at room temperature can help to lessen pain. Avoid placing it close to arteries or nerves. In adults, Penicillin G benzathine injection is injected into the upper outer quadrant of the buttock; in children younger than two years old, injection sites alternate for each dosage, with the injection going into the mid-lateral thigh muscle. This medication is available in prefilled syringes. It can be administered as a single dose.

Additional doses can be administered at least seven days apart if administered to treat or avoid specific dangerous infections. Patients should expect improvement in the first few days after injecting Penicillin G benzathine. However, contacting their healthcare practitioner immediately is critical if symptoms intensify or continue. Patients must also keep their checkups if their doctor has ordered higher dosages, even if they start feeling better. Missing doses or quitting therapy too soon can lead to an insufficient resolution of the infection and perhaps the emergence of antibiotic resistance.

Dietary Instructions:

Patients receiving Penicillin G benzathine injections should follow the usual diet unless instructed otherwise by a healthcare professional. Maintaining a nutritious and well-balanced diet is critical to support general health and facilitate recovery from any underlying problems being treated with medicine.

Side Effects:

Penicillin G benzathine injection has potential side effects. The mild side effects that are reported are:

• Vomiting and nausea.

• Bruises, bleeding, lumps, swelling, or discomfort at the injection site.

More serious side effects reported are:

• Hives and rashes.

• Itchiness.

• Difficulty in breathing and eating.

• Swelling in the hands, feet, ankles, eyes, throat, tongue, lips, and lower limbs.

• Fever.

• Pain in muscles and joints and headache.

• The heartbeat becomes fast.

• Extreme diarrhea (watery or bloody stools) with or without fever and cramping in the stomach that could last for up to two months or longer after the treatment.

• Abrupt onset of lower back pain.

• Numbness or blue or black discoloration in the injected arm or leg.

• Blistering, peeling, or shredding of the skin at the injection site

Missed Dose: If a Penicillin G benzathine injection is missed, it is critical to contact the doctor immediately to reschedule.

Overdose: It is imperative to take prompt action in case of an overdose of Penicillin G benzathine. Contact emergency services right away if the person is unconscious, has convulsions, is having trouble breathing, or is not able to be awakened. Trembling and convulsions are possible overdose symptoms.

Storage: Keep Penicillin G benzathine refrigerated at 36 degrees Fahrenheit and 46 degrees Fahrenheit (two degrees Celsius and eight degrees Celsius). The medicine should be kept carefully so that it does not freeze. Throw away any Penicillin G benzathine that is no longer needed or has expired. Make sure that youngsters cannot access this drug or any other medication.

For Doctors:

Indication -

• To preserve their effectiveness, Penicillin G benzathine can treat or prevent infections that are either proven or highly suspected to be caused by bacteria. Physicians must use information on susceptibility and culture whenever feasible when making treatment decisions.

• Penicillin G benzathine works well against infections caused by Penicillin-sensitive bacteria. It is very helpful for certain sexual infections, such as syphilis, bejel, yaws, and pinta, as well as mild to moderate upper respiratory infections caused by susceptible Streptococci.

• Penicillin G benzathine can be prophylactically taken to prevent the recurrence of medical diseases such as chorea and rheumatic fever. It also prevents follow-up in acute glomerulonephritis and rheumatic heart disease.

Contraindication: Penicillin G benzathine should not be used if there is a history of adverse response to any Penicillin.

What Are the Pharmacological Aspects of Penicillin G Benzathine?

• Description: Penicillin G benzathine is a drug injected deeply intramuscularly. Two Penicillin G molecules reacted with dibenzyl ethylene diamine to create Penicillin G benzathine. It is a white powder that is somewhat soluble in alcohol but not highly soluble in water. Penicillin G benzathine also contains Lecithin, carboxymethylcellulose, povidone, methylparaben, propylparaben, and sodium citrate buffer.

• Mechanism of Action: Penicillin G works as a bactericidal agent by preventing cell wall peptidoglycan formation in microorganisms susceptible to Penicillin during their active multiplication stage. As a result of this inhibition, the cell wall becomes osmotically unstable, which eventually causes bacterial death and cell lysis.

• Pharmacokinetics:

  • Serum proteins bind to about 60 percent of Penicillin G benzathine. With the kidneys having the highest concentrations and the skin, intestines, and liver having the lowest, it is distributed in different proportions across the human tissues. All other tissues and the spinal fluid are permeable to Penicillin G benzathine but to varying degrees. Tubular excretion quickly eliminates the medication in people with normal kidney function. Excretion is markedly delayed in neonates, small infants, and individuals with compromised kidney function.

  • Due to its incredibly low solubility, intramuscular injection sites release Penicillin G benzathine slowly. This is changed into Penicillin G through hydrolysis. Compared to other parenteral Penicillins, slow absorption and hydrolysis lead to lower but longer-lasting blood serum levels.

• Resistance: Penicillin is ineffective against bacteria that produce Penicillinase or species resistant to beta-lactams. However, Streptococcus pyogenes has not been documented to have Penicillin G benzathine resistance.

• Toxicity (Carcinogenesis, Mutagenesis, and Infertility): Since long-term animal studies have not been conducted on animals, no data exists.

Warnings and Precautions:

• Anaphylaxis: In patients receiving Penicillin medication, severe and occasionally deadly hypersensitivity responses, such as anaphylaxis, have been described. These reactions are more common in patients with a history of Penicillin hypersensitivity or sensitivity to numerous allergens. Severe reactions to Cephalosporin therapy have occurred in certain people with a history of Penicillin hypersensitivity. Carefully examining any history of Penicillin, cephalosporin, or other allergy hypersensitivity responses is necessary before starting Penicillin G benzathine. The proper treatment, such as the quick delivery of oxygen, Adrenaline, intravenous steroids, and airway care, should be given in case of an allergic reaction, and Penicillin G benzathine should be stopped.

• Diarrhea: Clostridium difficile-associated diarrhea (also known as CDAD) has been linked to almost all antibacterial drugs, including Penicillin G benzathine. This condition can range from moderate diarrhea to life-threatening colitis. Patients who have diarrhea after taking antibiotics should be evaluated for CDAD, and a thorough medical history is required because CDAD can happen even two months after taking antibiotics. If CDAD is suspected or proven, it may be necessary to stop using antibiotics not intended to treat C. difficile. Instead, appropriate management should be started as clinically indicated, such as protein supplementation, fluid and electrolyte management, antibiotic treatment of C. difficile, and surgical evaluation.

• Administration Method: Penicillin G benzathine and other Penicillin formulations accidentally injected intravascularly can cause serious neurovascular injury, such as transverse myelitis, gangrene that necessitates amputation, and necrosis at and around the injection site. These consequences have mostly been observed in newborns and young children, including acute extremity pallor, mottling, or cyanosis. Whenever there is any indication that the blood supply is impaired, it is imperative to consult a physician promptly. Since intravenous delivery of Penicillin G benzathine has been linked to cardiorespiratory arrest and mortality, it is recommended that Penicillin G benzathine only be provided through deep intramuscular injection in the upper outer quadrant of the buttock or the ventrolateral region. Because of the possibility of fibrosis and atrophy, injection into the anterolateral thigh is not advised.

• Drug Resistance: Penicillin G benzathine encourages the emergence of drug-resistant bacteria when there is no confirmed or highly suspected bacterial illness or preventive reason. Repeated antibiotic usage may cause non-susceptible organisms, including fungi, to increase excessively. As soon as a superinfection appears, the necessary action must be taken.

Drug Interaction:

• It is not advisable to provide tetracycline, a bacteriostatic antibiotic, concurrently with Penicillin as Tetracycline may counteract the Penicillin's bactericidal effect.

• Concomitant use of Probenecid with Penicillin has the potential to raise and sustain serum Penicillin levels. Probenecid works by competitively blocking the secretion of Penicillin from renal tubules, which lowers the drug's apparent volume of distribution and slows down its excretion rate.

Clinical Studies:

Few studies have evaluated the risk of major adverse responses to Penicillin G benzathine therapy in pregnant women as a means of preventing congenital syphilis, which limits the available evidence. No reports of negative reactions in the literature have been found. The likelihood of serious negative consequences was quite low in the general population. Thus, the benefits of treating pregnant women with Penicillin G benzathine to prevent congenital syphilis do not seem to outweigh the risks. However, more studies are required to improve the reliability of the data in this area.

Specific Considerations:

• Pregnancy: Research on the effects of Penicillin G on animals has not revealed any indications of decreased fertility or injury to the fetus. There are insufficient, well-monitored studies conducted on expectant mothers to definitively show that these medications do not have any detrimental impact on the developing fetus. Pregnancy should not be treated with this medication unless necessary, as research on animal reproduction does not always precisely anticipate human response.

• Nursing Mother: Penicillin G can pass into breast milk when given soluble. For this reason, giving Penicillin G benzathine to nursing moms should be done with caution.

• Geriatric Patients:

  • More patients 65 and older needed to be in clinical trials on Penicillin G benzathine to determine whether their responses differed from those of younger persons. On the other hand, prior clinical evidence indicates that older patients' responses do not differ much from younger patients' responses.

  • Elderly people should be prescribed with caution, usually at lower doses at first, because of the possibility of additional health problems or concomitant pharmaceutical use, as well as age-related reductions in liver, kidney, or cardiac function. Since the kidneys are primarily responsible for eliminating Penicillin G benzathine, senior people, who are more prone to poor renal function, may be more vulnerable to negative reactions.