Prostrep 20/20 50ml

Indications

• Tuberculosis
• Bacterial infections caused by susceptible strains of Mycobacteria
• Severe infections caused by Gram-negative bacteria

Dosage

Children: Refer to BNF for Children for appropriate pediatric dosing recommendations.

Adults: Refer to BNF for specific dosing guidance, as it may vary based on the indication and patient condition.

Mechanism of action

Dihydrostreptomycin binds to the 30S ribosomal subunit of bacteria, interfering with the initiation complex and causing misreading of the mRNA. This action leads to the production of nonfunctional proteins and ultimately results in bacterial cell death.

Pharmacodynamics

Dihydrostreptomycin exhibits concentration-dependent bactericidal activity against a variety of Gram-negative and some Gram-positive bacteria. Its efficacy is influenced by the peak concentration achieved relative to the minimum inhibitory concentration (MIC) of the organism.

Pharmacokinetics

Dihydrostreptomycin is administered parenterally due to poor oral absorption. It is widely distributed in body tissues and fluids, but does not penetrate well into the central nervous system. The drug is primarily eliminated by renal excretion, and its half-life can be prolonged in patients with renal impairment.

Contra-indications

• Hypersensitivity to dihydrostreptomycin or other aminoglycosides
• Severe renal impairment
• Myasthenia gravis

Adverse effects

• Ototoxicity, including hearing loss and vestibular dysfunction
• Nephrotoxicity, particularly with high doses or prolonged therapy
• Neuromuscular blockade
• Allergic reactions, including rash and anaphylaxis

Interactions

• Increased risk of nephrotoxicity with other nephrotoxic agents such as vancomycin, amphotericin B, and non-steroidal anti-inflammatory drugs (NSAIDs)
• Potentially enhanced neuromuscular blockade with neuromuscular blockers

Precautions

• Use with caution in patients with pre-existing renal impairment
• Monitor renal function regularly during therapy
• Assess hearing function prior to and during treatment

Pregnancy

Dihydrostreptomycin is categorized as a category D drug. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Dihydrostreptomycin is excreted in breast milk. Caution should be exercised when administering to breastfeeding women.

Storage

Store in a cool, dry place away from direct light. Keep out of reach of children.

Formulations

• Injection solution

Indications

• Bacterial infections
• Pneumonia
• Streptococcal infections
• Syphilis
• Meningitis
• Endocarditis
• Skin infections

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations based on the type of penicillin and indication.

Adults: Refer to the BNF for specific dosing recommendations based on the type of penicillin and indication.

Mechanism of action

Penicillin targets penicillin-binding proteins (PBPs) located inside the bacterial cell wall. By binding to these proteins, penicillin disrupts the transpeptidation process, which is essential for cell wall structural integrity. This results in weakened cell walls, causing osmotic instability and ultimately leading to cell lysis and death.

Pharmacodynamics

Penicillin exhibits bactericidal activity, meaning that it kills bacteria rather than merely inhibiting their growth. Its effectiveness is generally dependent on the growth phase of the bacteria, as it is most active against actively dividing cells. The spectrum of activity varies among different penicillins, with some being more effective against specific bacterial strains.

Pharmacokinetics

Penicillin is primarily absorbed in the gastrointestinal tract, with its bioavailability varying depending on the specific type of penicillin. It is primarily excreted by the kidneys, with a half-life that typically ranges from 30 minutes to 2 hours, depending on the formulation. Dosage adjustments may be necessary in patients with renal impairment to prevent accumulation and toxicity.

Contra-indications

• History of hypersensitivity to penicillins
• Severe allergic reactions to beta-lactam antibiotics

Adverse effects

• Allergic reactions such as rash, urticaria, and anaphylaxis
• Gastrointestinal disturbances including nausea, vomiting, and diarrhea
• Superinfection due to alteration of normal flora
• Hematologic reactions such as leukopenia, thrombocytopenia

Interactions

• valproate+penicillins: Severe (increases risk of adverse effects)
• allopurinol+penicillins: Unknown (increases risk of skin rash)
• leflunomide+penicillins: Unknown (increases exposure)
• nitisinone+penicillins: Unknown (increases exposure)
• penicillins+phenindione: Unknown (increases risk of bleeding events)
• teriflunomide+penicillins: Unknown (increases exposure)

Precautions

• Use with caution in patients with renal impairment
• Monitor for signs of allergic reactions
• Consider alternative therapy in patients with a history of severe allergies

Pregnancy

Penicillins are generally considered safe to use during pregnancy; however, consult local guidelines and assess benefits versus risks.

Breast-feeding

Penicillins are excreted in breast milk in small amounts; generally considered safe, but monitor infant for possible effects.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Oral tablets
• Oral suspension
• Intravenous injection
• Intramuscular injection