BIOGRAS

Indications

• Oral hygiene
• Skin antisepsis
• Bladder irrigation
• Urological surgery
• Management of infections associated with indwelling urinary catheters

Mechanism of action

Chlorhexidine's antimicrobial effects arise from its ability to disrupt microbial cell membranes. The positively charged chlorhexidine molecule interacts with negatively charged phosphate groups on microbial surfaces, compromising cell integrity and causing leakage of intracellular materials. This interaction allows chlorhexidine to enter the cell, precipitate cytoplasmic components, and ultimately induce cell death. At lower concentrations, chlorhexidine acts as a bacteriostatic agent, causing leakage of substances like potassium and phosphorus, while at higher concentrations, it exerts bactericidal effects.

Pharmacodynamics

Chlorhexidine exhibits broad-spectrum antimicrobial activity, effective against a variety of bacteria, yeasts, and viruses. Its action is dose-dependent, with lower concentrations (0.02%-0.06%) providing bacteriostatic effects, while higher concentrations (>0.12%) are bactericidal. Pharmacokinetic studies indicate that about 30% of chlorhexidine remains in the mouth after rinsing, allowing for slow release into oral fluids. This property, known as 'substantivity', helps prevent microbial colonization on surfaces like dentine, although prolonged use can lead to staining of oral surfaces.

Pharmacokinetics

Chlorhexidine is retained in the oral cavity at approximately 30% following rinsing, with a slow release into saliva. The pharmacokinetics of chlorhexidine indicate a high affinity for binding to tissues, which prolongs its antimicrobial action. The systemic absorption of chlorhexidine is minimal when used topically or as a rinse, making it safe for localized use. The elimination half-life and metabolism details are not well documented due to its primarily topical application.

Adverse effects

• Mucosal irritation
• Burning sensation
• Staining of teeth and oral surfaces
• Allergic reactions

Precautions

• Use with caution in patients with a history of hypersensitivity to chlorhexidine
• May cause irritation; discontinue if severe irritation occurs
• Staining may occur with prolonged use, particularly with oral formulations

Pregnancy

Chlorhexidine is generally considered safe for use during pregnancy; however, caution is advised and pregnant individuals should consult healthcare providers.

Breast-feeding

Chlorhexidine is considered safe during breastfeeding, but it is advisable to consult a healthcare provider.

Storage

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

Formulations

• Irrigation solution (0.02% and 0.05%)
• Capsules (various strengths)
• Catheter maintenance solution (1:5000)
• Topical solutions for oral hygiene

Indications

• Acute wounds
• Chronic wounds
• Surgical wounds
• Burns
• Pressure ulcers
• Diabetic foot ulcers

Dosage

Children: Refer to the relevant guidelines based on the specific type of wound and dressing used, considering the age and size of the child.

Adults: Dressings should be applied according to the type of wound and the dressing selected. Change the dressing as needed based on exudate levels and manufacturer's instructions.

Mechanism of action

Dressings provide a moist environment that facilitates healing, allowing cells to migrate and proliferate. They can absorb exudate, protect the wound from external contaminants, and maintain temperature, which is essential for cellular activity in the healing process.

Pharmacodynamics

The pharmacodynamic properties of dressings are primarily dependent on their composition and design. For example, hydrocolloid dressings swell in the presence of wound exudate, creating a gel-like substance that aids in moist wound healing. Some dressings may also have antimicrobial properties to reduce the risk of infection.

Pharmacokinetics

Dressings do not have pharmacokinetic properties in the traditional sense as they are not absorbed into the system. Instead, their effectiveness is determined by their ability to remain intact on the wound, manage exudate, and facilitate the healing process until the wound has sufficiently healed.

Pregnancy

Consult with a healthcare provider before use, as the safety of specific dressing materials during pregnancy may vary.

Breast-feeding

Consult with a healthcare provider regarding the use of dressings while breastfeeding, as some materials may not be advisable.

Storage

Store in a cool, dry place away from direct sunlight. Ensure dressings are kept in their original packaging until use to maintain sterility.

Formulations

• Hydrocolloid dressings
• Foam dressings
• Alginate dressings
• Transparent film dressings
• Hydrogels
• Antimicrobial dressings

Indications

• Acute wounds
• Chronic wounds
• Surgical incisions
• Burns
• Pressure ulcers
• Trauma wounds

Dosage

Children: Refer to the guidance for adult dosing, as pediatric use is similar and should be based on clinical assessment of the wound and exudate.

Adults: The dosage or application frequency of gauze depends on the specific wound type and the amount of exudate. It is typically changed as needed, based on clinical assessment.

Mechanism of action

Gauze functions primarily as a physical barrier to protect wounds from external contaminants and further injury. It absorbs exudate from wounds, which helps to maintain a moist environment conducive to healing. The open weave of gauze allows for breathability, which is essential in preventing maceration of the surrounding skin.

Pharmacodynamics

As a non-pharmacological product, gauze does not have pharmacodynamic properties in the traditional sense. Its effectiveness is related to its physical characteristics, such as absorbency, flexibility, and ability to protect wounds. The interaction with the wound environment aids in managing exudate and reducing the risk of infection.

Pharmacokinetics

Gauze does not undergo pharmacokinetic processes such as absorption, distribution, metabolism, or excretion, as it is not an active pharmaceutical ingredient. Instead, it provides a mechanical function in wound management. The duration of action is dependent on the frequency of dressing changes, which is influenced by the amount of exudate produced by the wound.

Pregnancy

Gauze is considered safe for use during pregnancy as it is a non-pharmacological material used primarily for wound care.

Breast-feeding

Gauze is safe for use during breastfeeding, as it is unlikely to affect breast milk or the nursing infant.

Storage

Store in a cool, dry place, away from direct sunlight and moisture. Ensure that the packaging remains sealed until use to prevent contamination.

Formulations

• Sterile gauze pads
• Non-sterile gauze pads
• Gauze rolls

Mechanism of action

Chlorhexidine’s broad-spectrum antimicrobial effects are due to its ability to disrupt microbial cell membranes. The positively charged chlorhexidine molecule reacts with negatively charged phosphate groups on microbial cell surfaces - this reaction both destroys the integrity of the cell, allowing leakage of intracellular material, and allows chlorhexidine to enter the cell, causing precipitation of cytoplasmic components and ultimately cell death. The specific means of cell death is dependent on the concentration of chlorhexidine - lower concentrations are bacteriostatic and result in leakage of intracellular substances such as potassium and phosphorous, whereas higher concentrations are bactericidal and cause cytoplasmic precipitation.

Pharmacodynamics

Chlorhexidine is a broad-spectrum antimicrobial with demonstrated activity against both gram-positive and gram-negative bacteria, yeasts, and viruses. Antimicrobial activity is dose-dependent - chlorhexidine is bacteriostatic at lower concentrations (0.02%-0.06%) and bactericidal at higher concentrations (>0.12%). Pharmacokinetic studies of oral chlorhexidine rinses indicate that approximately 30% of the active ingredient is retained in the mouth following rinsing, which is subsequently slowly released into oral fluids. This ability to adsorb to dentine, shared with tetracycline antibiotics such as [doxycycline], is known as "substantivity" and is the result of chlorhexidine's positive charge - it is likely that this substantivity plays at least some role in chlorhexidine's antimicrobial activity, as its persistence on surfaces such as dentine prevent microbial colonization. Dental chlorhexidine rinses may result in staining of oral surfaces, such as teeth. This effect is not ubiquitous and appears to be more significant with extended therapy (i.e. up to 6 months) - nevertheless, patients for whom oral staining is unacceptable should use chlorhexidine rinse with caution and for the shortest effective interval. Allergic reactions to chlorhexidine have been associated with the development of anaphylaxis.