OTOCOL EAR DROPS

Indications

• Topical anesthesia for minor skin irritations
• Sore throat relief
• Dental procedures

Dosage

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

Adults: Apply a thin layer to the affected area as needed, not exceeding the recommended frequency in product guidelines.

Mechanism of action

Benzocaine diffuses into nerve cells where it binds to sodium channels, preventing the channels from opening, and blocking the influx of sodium ions. Nerve cells unable to allow sodium into cells cannot depolarize and conduct nerve impulses. Benzocaine reversibly stabilizes the neuronal membrane, decreasing its permeability to sodium ions, thereby inhibiting depolarization of the neuronal membrane and blocking the initiation and conduction of nerve impulses.

Pharmacodynamics

Benzocaine is indicated for use as a topical anesthetic. It has a duration of action of approximately 10 minutes and a wide therapeutic window. Patients should be counselled regarding the risks of methemoglobinemia, a rare but serious condition that can occur with excessive use.

Pharmacokinetics

Benzocaine is poorly soluble in water, which limits its systemic absorption when applied topically. It is rapidly absorbed through the skin, and its effects are localized. The half-life and metabolism details are not extensively documented, but the drug is primarily metabolized in the liver. Clearance from the system generally occurs within a short time frame, correlating with its brief duration of action.

Adverse effects

• Methemoglobinemia
• Allergic reactions
• Local irritation
• Skin rash

Precautions

• Use with caution in patients with a history of methemoglobinemia
• Not for use on large areas of damaged skin or mucous membranes
• Avoid contact with eyes

Pregnancy

Benzocaine should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus. Consult a healthcare professional.

Breast-feeding

Benzocaine is generally considered safe for use during breastfeeding, but caution is advised. Consult a healthcare professional for specific recommendations.

Storage

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

Formulations

• Topical cream
• Topical gel
• Topical ointment
• Lozenges

Indications

• Bacterial infections
• Typhoid fever
• Severe bacterial eye infections
• Bacterial meningitis

Mechanism of action

Chloramphenicol diffuses through the bacterial cell membrane due to its lipid solubility. It reversibly binds to the L16 protein of the 50S subunit of bacterial ribosomes, inhibiting the transfer of amino acids to growing peptide chains by suppressing peptidyl transferase activity. This action prevents peptide bond formation and thus protein synthesis. In addition, chloramphenicol can inhibit mitochondrial protein synthesis in mammalian cells, as mitochondrial ribosomes resemble bacterial ribosomes more than they do mammalian cytoplasmic ribosomes.

Pharmacodynamics

Chloramphenicol is classified as a bacteriostatic antibiotic, meaning it inhibits the growth of bacteria rather than killing them directly. However, at high concentrations or against particularly susceptible organisms, it can exhibit bactericidal properties. The drug is effective against a variety of pathogens, making it useful for treating serious infections. Due to its side effects, particularly hematologic toxicity, chloramphenicol is used cautiously and is often restricted to life-threatening infections where other treatments are not appropriate.

Pharmacokinetics

Chloramphenicol is well-absorbed after oral administration and can penetrate tissues and body fluids, including the central nervous system, making it effective for treating infections in various sites. It is metabolized in the liver, and its elimination half-life can be prolonged in individuals with hepatic impairment. The drug is also excreted in urine, primarily as metabolites, but some unchanged drug may also be present. Dose adjustments may be necessary in cases of liver and kidney impairment to avoid toxicity.

Contra-indications

• Children under 12 years
• Pregnant women
• Patients with a history of cholestasis

Adverse effects

• Agranulocytosis
• Aplastic anaemia
• Nephritis
• Renal impairment
• Gastrointestinal discomfort
• Decreased appetite
• Diarrhoea
• Dizziness
• Toxic epidermal necrolysis
• Hepatotoxicity
• Stomatitis

Interactions

• Chloramphenicol + Guanfacine: Unknown (increases exposure)
• Chloramphenicol + Iron: Unknown (decreases efficacy)
• Chloramphenicol + Sulfonylureas: Unknown (increases exposure)
• Chloramphenicol + Tacrolimus: Unknown (increases concentration)
• Rifampicin + Chloramphenicol: Unknown (decreases concentration)

Precautions

• Caution in hepatic impairment
• Caution in renal impairment
• Use in high doses with caution due to risk of hepatotoxicity
• Monitor for signs of bone marrow suppression

Pregnancy

Chloramphenicol should not be given to pregnant women due to risks of effects on skeletal development and potential for discoloration of the child's teeth. Use only if potential benefit outweighs risk.

Breast-feeding

Manufacturer advises avoiding use during breastfeeding as it is present in milk and may pose risks to the infant.

Storage

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

Formulations

• Tablet
• Capsule
• Oral solution
• Powder for solution for infusion

Mechanism of action

Benzocaine diffuses into nerve cells where it binds to sodium channels, preventing the channels from opening, and blocking the influx of sodium ions. Nerve cells unable to allow sodium into cells cannot depolarize and conduct nerve impulses. Benzocaine reversibly stabilizes the neuronal membrane with decreases its permeability to sodium ions. Depolarization of the neuronal membrane is inhibited thereby blocking the initiation and conduction of nerve impulses.

Pharmacodynamics

Benzocaine is indicated for use as a topical anesthetic. It has a duration of action of approximately 10 minutes and a wide therapeutic window. Patients should be counselled regarding the risks of methemoglobinemia.

Mechanism of action

Chloramphenicol is lipid-soluble, allowing it to diffuse through the bacterial cell membrane. It then reversibly binds to the L16 protein of the 50S subunit of bacterial ribosomes, where transfer of amino acids to growing peptide chains is prevented (perhaps by suppression of peptidyl transferase activity), thus inhibiting peptide bond formation and subsequent protein synthesis. Chloramphenicol inhibits protein synthesis in bacteria, and to a lesser extent, in eukaryotic cells. The drug readily penetrates bacterial cells, probably by facilitated diffusion. Chloramphenicol acts primarily by binding reversibly to the 50S ribosomal subunit (near the binding site for the macrolide antibiotics and clindamycin, which chloramphenicol inhibits competitively). Although binding of tRNA at the codon recognition site on the 30S ribosomal subunit is undisturbed, the drug apparently prevents the binding of the amino acid-containing end of the aminoacyl tRNA to the acceptor site on the 50S ribosomal subunit. The interaction between peptidyltransferase and its amino acid substrate cannot occur, and peptide bond formation is inhibited. Chloramphenicol ... can inhibit mitochondrial protein synthesis in mammalian cells, perhaps because mitochondrial ribosomes resemble bacterial ribosomes (both are 70S) more than they do the 80S cytoplasmic ribosomes of mammalian cells. The peptidyltransferase of mitochondrial ribosomes, but not of cytoplasmic ribosomes, is inhibited by chloramphenicol. Mammalian erythropoietic cells are particularly sensitive to the drug. /Chloramphenicol/ inhibits bacterial protein synthesis by interfering with the transfer of activated amino acids from soluble RNA to ribosomes. In vitro, chloramphenicol exerts mainly a bacteriostatic effect on a wide range of gram-negative and gram-positive bacteria. /Chloramphenicol/ acts by inhibition of protein synthesis by interfering with the transfer of activated amino acids from soluble RNA to ribosomes. For more Mechanism of Action (Complete) data for Chloramphenicol (9 total), please visit the HSDB record page.

Pharmacodynamics

Chloramphenicol is a broad-spectrum antibiotic that was derived from the bacterium Streptomyces venezuelae and is now produced synthetically. Chloramphenicol is effective against a wide variety of microorganisms, but due to serious side-effects (e.g., damage to the bone marrow, including aplastic anemia) in humans, it is usually reserved for the treatment of serious and life-threatening infections (e.g., typhoid fever). Chloramphenicol is bacteriostatic but may be bactericidal in high concentrations or when used against highly susceptible organisms. Chloramphenicol stops bacterial growth by binding to the bacterial ribosome (blocking peptidyl transferase) and inhibiting protein synthesis.