STREPEN VET INJECTION

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

Indications

• Local anesthesia for dental procedures
• Regional anesthesia for minor surgical interventions
• Pain relief in localized areas

Dosage

Children: Refer to the BNF for Children for specific dosing information.

Adults: Refer to the BNF for specific dosing information.

Mechanism of action

Procaine acts mainly by inhibiting sodium influx through voltage-gated sodium channels in the neuronal cell membrane of peripheral nerves. By interrupting sodium influx, the generation of action potentials is inhibited, thereby blocking signal conduction. Procaine also interacts with N-methyl-D-aspartate (NMDA) receptors, nicotinic acetylcholine receptors, and serotonin receptor-ion channel complexes, contributing to its anesthetic effects. It reduces membrane permeability to both sodium and potassium ions, increasing the electrical excitability threshold and slowing impulse conduction.

Pharmacodynamics

Procaine is indicated for producing local or regional anesthesia, particularly in oral surgery. Its vasoconstrictive properties help minimize blood loss during procedures. As an ester anesthetic, procaine is metabolized in the plasma by pseudocholinesterase, leading to the formation of para-aminobenzoic acid (PABA), which is excreted in urine. Compared to other local anesthetics like lidocaine, procaine has a unique profile that can be beneficial in specific surgical contexts.

Pharmacokinetics

Procaine is rapidly metabolized in the bloodstream, with its effects typically lasting for a short duration. The onset of anesthesia is relatively quick, but the duration of action is shorter than that of other longer-acting local anesthetics. The primary route of elimination for procaine and its metabolites is renal excretion. The pharmacokinetics can be influenced by factors such as the site of injection and the presence of vasoconstrictors.

Contra-indications

• Hypersensitivity to procaine or other local anesthetics
• Severe liver or kidney disease
• Myasthenia gravis

Adverse effects

• Allergic reactions including rash and anaphylaxis
• Nausea and vomiting
• Dizziness
• Headache
• Cardiovascular effects such as arrhythmias
• Nerve damage or prolonged numbness at the injection site

Interactions

• Increased risk of systemic toxicity when used with other local anesthetics
• Potential interaction with cholinesterase inhibitors
• May enhance the effects of other CNS depressants

Precautions

• Use with caution in patients with cardiovascular disease
• Careful monitoring is required in patients with a history of seizures
• Avoid use in patients with significant hypovolemia

Pregnancy

Procaine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Consult local guidelines and conduct a risk assessment.

Breast-feeding

Procaine is excreted in breast milk; caution should be exercised when administering to nursing mothers.

Storage

Store at room temperature, away from light and moisture. Keep out of reach of children.

Formulations

• Injection solution

Mechanism of action

Procaine acts mainly by inhibiting sodium influx through voltage gated sodium channels in the neuronal cell membrane of peripheral nerves. When the influx of sodium is interrupted, an action potential cannot arise and signal conduction is thus inhibited. The receptor site is thought to be located at the cytoplasmic (inner) portion of the sodium channel. Procaine has also been shown to bind or antagonize the function of N-methyl-D-aspartate (NMDA) receptors as well as nicotinic acetylcholine receptors and the serotonin receptor-ion channel complex. LOCAL ANESTHETICS BLOCK CONDUCTION BY DECREASING OR PREVENTING THE LARGE TRANSIENT INCREASE IN THE PERMEABILITY OF EXCITABLE MEMBRANES TO SODIUM IONS THAT NORMALLY IS PRODUCED BY A SLIGHT DEPOLARIZATION OF THE MEMBRANE. /LOCAL ANESTHETIC/ LOCAL ANESTHETICS BLOCK CONDUCTION IN NERVE PERHAPS BY COMPETING WITH CALCIUM @ SOME SITE THAT CONTROLS PERMEABILITY OF MEMBRANE. ... LOCAL ANESTHETICS ALSO REDUCE PERMEABILITY OF RESTING NERVE TO POTASSIUM AS WELL AS TO SODIUM IONS. /LOCAL ANESTHETICS/ AS THE ANESTHETIC ACTION PROGRESSIVELY DEVELOPS IN A NERVE, THE THRESHOLD FOR ELECTRICAL EXCITABILITY GRADUALLY INCREASES, THE RATE OF RISE OF THE ACTION POTENTIAL DECLINES, IMPULSE CONDUCTION SLOWS, & THE SAFETY FACTOR FOR CONDUCTION DECREASES; THESE FACTORS DECREASE THE PROBABILITY OF PROPAGATION OF THE ACTION POTENTIAL, AND NERVE CONDUCTION FAILS. /LOCAL ANESTHETICS/ POSTSYNAPTIC ACTION ... END-PLATE CURRENT IS MUCH PROLONGED BY PROCAINE. SIMILARLY, WHEN ... ADDED TO FLUID PERFUSING GANGLION, PREGANGLIONIC STIMULATION FAILS TO ELICIT POSTGANGLIONIC DISCHARGES & GANGLION CELLS BECOME INSENSITIVE TO STIMULATION BY ACETYLCHOLINE. IN ADDITION TO BLOCKING CONDITIONS IN NERVE AXONS IN THE PERIPHERAL NERVOUS SYSTEM, LOCAL ANESTHETICS INTERFERE WITH THE FUNCTION OF ALL ORGANS IN WHICH CONDUCTION OR TRANSMISSION OF IMPULSES OCCURS. ... EFFECTS ON ... CNS, THE AUTONOMIC GANGLIA, THE NEUROMUSCULAR JUNCTION, & ALL FORMS OF MUSCLE. /LOCAL ANESTHETICS/

Pharmacodynamics

Procaine is an anesthetic agent indicated for production of local or regional anesthesia, particularly for oral surgery. Procaine (like cocaine) has the advantage of constricting blood vessels which reduces bleeding, unlike other local anesthetics like lidocaine. Procaine is an ester anesthetic. It is metabolized in the plasma by the enzyme pseudocholinesterase through hydrolysis into para-aminobenzoic acid (PABA), which is then excreted by the kidneys into the urine.