Centre-Oxyte 10% Injection

Indications

• Bacterial infections (e.g. Chlamydia, Rickettsia, Mycoplasma)
• Acne
• Prophylaxis of asymptomatic meningococcal carrier state (not recommended)

Dosage

Adults: For adult patients, the typical dosage of oxytetracycline for susceptible infections is 100 mg twice daily for 5 days. For other conditions, such as acne, the dosage may be 500 mg twice daily, usually for a duration of 6 to 12 weeks, with the possibility of repeating the course intermittently.

Mechanism of action

Oxytetracycline exerts its antibacterial effects by binding to the 30S ribosomal subunit of bacteria, inhibiting the binding of aminoacyl-tRNA to the mRNA-ribosome complex. This action prevents the synthesis of proteins essential for bacterial growth and replication, leading to the bacteriostatic effect of the drug.

Pharmacodynamics

The pharmacodynamics of oxytetracycline involve its ability to inhibit bacterial protein synthesis, which is critical for the growth and reproduction of bacteria. The drug demonstrates a broad spectrum of activity against both Gram-positive and Gram-negative organisms, as well as some atypical pathogens. Its effectiveness can be influenced by the presence of tetracycline resistance mechanisms in certain bacterial strains.

Pharmacokinetics

Oxytetracycline is well absorbed from the gastrointestinal tract, with peak plasma concentrations occurring approximately 1-2 hours after oral administration. It has a relatively long half-life of about 8-10 hours, allowing for twice-daily dosing. The drug is widely distributed in body tissues and fluids, including the liver, kidneys, and lungs, but is less effective in central nervous system infections due to limited penetration. It is primarily excreted via urine, and dosage adjustments may be necessary in patients with renal impairment.

Contra-indications

• Children under 12 years due to deposition in growing bone and teeth, causing staining and occasionally dental hypoplasia

Adverse effects

• Gastrointestinal disturbances
• Photosensitivity
• Dental discoloration
• Hepatotoxicity
• Renal impairment
• Skin reactions including rash and urticaria
• Ataxia
• Hearing impairment
• Colitis
• Systemic lupus erythematosus exacerbation

Interactions

• Antacids and supplements containing calcium, magnesium, or iron may reduce absorption
• Oral contraceptives may be less effective
• Other tetracyclines
• Warfarin (may increase anticoagulant effect)

Precautions

• Use with caution in patients with renal impairment
• Monitor for hepatic toxicity in long-term use
• Patients should be advised to avoid excessive sunlight exposure
• Discontinue if systemic lupus erythematosus develops or worsens

Pregnancy

Oxytetracycline is contraindicated during pregnancy due to potential harm to fetal development, particularly affecting bone and dental health.

Breast-feeding

Use with caution; oxytetracycline is excreted in breast milk and may affect the infant's dental health.

Storage

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

Formulations

• Oxytetracycline 250 mg tablets
• Oxytetracycline oral suspension
• Oxytetracycline oral solution

Indications

• Solvent in pharmaceutical formulations
• Moisturizer and humectant in topical applications
• Potential use in the management of drug solubility issues

Dosage

Children: Refer to specific formulations and clinical guidelines, as dosing varies widely based on the application and formulation.

Adults: Refer to specific formulations and clinical guidelines, as dosing varies widely based on the application and formulation.

Mechanism of action

Glycols, particularly propylene glycol, act as humectants, which help to retain moisture in formulations. They can also enhance the solubility of drugs, aiding in their absorption when used as excipients. Propylene glycol is metabolized in the liver to lactate and subsequently to glucose, providing a source of energy when utilized in metabolic pathways.

Pharmacodynamics

The pharmacodynamics of glycols involve their ability to modulate the viscosity of solutions and enhance the solubility of other compounds. Propylene glycol can also facilitate the absorption of other drugs when used in formulations. It exhibits a low toxicity profile when used appropriately, but excessive systemic exposure can lead to metabolic acidosis and other adverse effects.

Pharmacokinetics

Glycols are rapidly absorbed when administered intravenously or orally. Propylene glycol is metabolized primarily in the liver, with a half-life varying based on the dose and individual metabolism. Renal excretion plays a role in the elimination of metabolites. Accumulation can occur in individuals with impaired liver or kidney function, necessitating careful monitoring of dosing in such populations.

Pregnancy

The safety of glycol in pregnancy is not well established. Consult healthcare professionals before use.

Breast-feeding

Glycol's effects during breastfeeding are not well characterized. Caution is advised.

Storage

Store in a cool, dry place away from direct sunlight and moisture.

Dosage

Children: Refer to specific medication guidelines for dosing.

Adults: Refer to specific medication guidelines for dosing.

Dosage

Children: Paediatric fluid requirements should be calculated based on age, weight, and clinical condition. Refer to the guidelines in the BNF for Children for detailed recommendations.

Adults: Dosage in litres may vary depending on clinical circumstances, such as fluid resuscitation needs, maintenance fluid requirements, or medication delivery. Refer to clinical guidelines for specific scenarios.

Mechanism of action

Litres do not have a pharmacological mechanism of action as they are a unit of measurement rather than a drug. However, the administration of fluids measured in litres can influence various physiological processes, including hydration status, electrolyte balance, and overall fluid homeostasis in the body.

Pharmacodynamics

As a measurement unit, litres do not exhibit pharmacodynamics. However, the volume of fluid administered can impact the pharmacodynamics of medications that are diluted or delivered in fluid form, affecting the rate of absorption, distribution, metabolism, and excretion of drugs.

Pharmacokinetics

Litres as a unit of volume do not possess pharmacokinetic properties. The pharmacokinetics of a drug may be influenced by the volume of fluid in which it is administered, as this can affect the concentration of the drug in the bloodstream and its subsequent pharmacological effects.

Indications

• Plant growth regulation
• Agricultural applications as a growth inhibitor

Dosage

Children: Not applicable.

Adults: Refer to the relevant agricultural guidelines for specific applications.

Mechanism of action

In an in vitro study, propylene acts as a plant growth inhibitor by inhibiting the oxidation of indole-3-acetic acid by peroxidase in the presence of superoxide anion radicals. This inhibition is linked to the activation of an iron complex (compound III) shuttle, which enhances the reaction rate between superoxide and peroxidase, ultimately affecting plant growth processes. Propylene is a less effective inhibitor compared to ethylene.

Pharmacodynamics

The pharmacodynamic effects of propylene are primarily observed in its role as a growth inhibitor in plants. By modulating the oxidation of phytohormones like indole-3-acetic acid, propylene can influence various growth responses in plants, potentially affecting processes such as cell elongation and division.

Pharmacokinetics

Information on the pharmacokinetics of propylene in humans is not well-documented, as its primary uses are industrial and agricultural. Its metabolism may be influenced by environmental factors, and its effects are primarily studied in the context of plant biology rather than human pharmacology.

Indications

• Surgical procedures
• Injection of medications
• Preparation of sterile pharmaceutical products
• Management of open wounds
• Use in controlled environments such as hospitals and laboratories

Dosage

Children: Refer to specific drug monographs for dosage information as sterile itself is not a pharmacological agent.

Adults: Refer to specific drug monographs for dosage information as sterile itself is not a pharmacological agent.

Mechanism of action

Sterility itself does not have a mechanism of action as it is a state of cleanliness and does not interact with biological systems. However, the methods used to achieve sterility, such as heat or chemical agents, act by denaturing proteins, disrupting cellular structures, or damaging nucleic acids in microorganisms, leading to their inactivation or destruction.

Pharmacodynamics

The pharmacodynamics of sterile techniques primarily involves the prevention of microbial infection and contamination when administering medications. By ensuring that products are sterile, the risk of adverse effects related to infections is minimized. The effectiveness of sterilization methods can be influenced by factors such as temperature, duration of exposure, and the type of microorganisms present.

Pharmacokinetics

As sterility does not pertain to a specific drug, pharmacokinetics is not applicable. However, the pharmacokinetics of a drug will depend on its formulation, route of administration, and the presence of preservatives or stabilizers that may be used alongside sterile preparations.

Pregnancy

Sterile preparations are generally considered safe during pregnancy as they are used to provide hydration, nutrition, or medications in a controlled manner, but specific formulations should be assessed individually.

Breast-feeding

Sterile solutions used for hydration or nutritional support are typically safe during breastfeeding, but any specific additives or medications within the solutions should be evaluated for safety.

Storage

Sterile solutions should be stored in a cool, dry place, protected from light, and should be used before the expiration date. Once opened, they may have specific storage requirements based on the formulation.

Formulations

• Sterile saline solution
• Sterile water for injection
• Sterile dextrose solution
• Sterile electrolyte solutions

Indications

• Topical treatment of skin conditions
• Emulsifying agent in pharmaceutical formulations
• Alkalizing agent in topical preparations

Dosage

Children: Refer to the BNF for Children for appropriate paediatric dosing, as it will provide specific guidance based on age and condition.

Adults: Refer to the specific product guidelines for adult dosing as it may vary based on formulation and intended use.

Mechanism of action

As an amine, trolamine can accept a hydrogen ion to form hydroxide and a conjugate acid, thereby increasing the pH of the solution. As a surfactant, it reduces interfacial tension, which helps to prevent the separation of emulsions or the precipitation of compounds out of solution.

Pharmacodynamics

Trolamine acts as a surfactant or alkalizing agent, facilitating the emulsification and solubilization of compounds. Its ability to raise the pH of a solution enhances the stability and effectiveness of various formulations.

Pharmacokinetics

Information specific to the pharmacokinetics of trolamine is not provided. Generally, the absorption, distribution, metabolism, and excretion of surfactants and alkalizing agents can vary based on formulation and route of administration. For topical applications, systemic absorption may be minimal.

Pregnancy

There is limited data on the use of trolamine during pregnancy. It should be used only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Trolamine is not expected to be excreted in significant amounts in breast milk. Caution is advised when administering to nursing mothers.

Storage

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

Formulations

• Topical cream
• Topical gel

Mechanism of action

In an in vitro study of the mechanism of action of ethylene as a plant growth inhibitor, the effects of ethylene and some of its analogs, including propylene, on the oxidation of indole-3-acetic acid were examined. Ethylene and its analogs inhibited the oxidation of indole-3-acetic acid by peroxidase under conditions where the iron complex (compound III, an oxy-ferrous complex of peroxidase) shuttle was activated. Inhibition occurred only in the presence of the superoxide anion radical 02(-). Spectral and kinetic data indicated that ethylene and its analogs enhanced the rate of reaction of 02(-) with peroxidase; ie, the iron complex (compound III) shuttle, resulting in the formation of compound III. Propylene was a less effective inhibitor than ethylene.

Mechanism of action

As an amine, trolamine is capable of accepting a hydrogen to form hydroxide and a conjugate acid. This raises the pH of the solution. As a surfactant, it can lower the interfacial tension in a mixture or solution to prevent separation of emulsions or precipitation of a compound out of solution.

Pharmacodynamics

Acts as a surfactant or alkalizing agent to aid in emulsification and solubilizing of compounds or in raising the pH of a solution