Dermogard

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

• Wound healing
• Skin irritations
• Dry skin conditions
• Eczema
• Psoriasis

Dosage

Children: Refer to the BNF for Children for appropriate dosing and formulation guidance for paediatric use.

Adults: Refer to specific product guidelines for application frequency and amount, as allantoin is typically used in topical formulations.

Mechanism of action

Although there is no well-controlled data to formally substantiate its method of action, studies suggest that allantoin may induce a histological wound healing profile. This profile includes increased vasodilation, inflammatory exudate presence, and enhanced numbers of inflammatory cells, angiogenesis, fibroblast proliferation, and collagen deposition in wound sites treated with allantoin compared to untreated ones.

Pharmacodynamics

Ongoing studies indicate that allantoin possesses moisturizing and keratolytic effects. It can increase the water content of the extracellular matrix and promote the desquamation of the upper layers of dead skin cells. These activities are believed to support cell proliferation and facilitate wound healing.

Pharmacokinetics

The pharmacokinetics of allantoin are not well characterized in controlled studies. However, its application as a topical agent suggests localized effects with minimal systemic absorption, facilitating its use in dermatological applications without significant systemic effects.

Pregnancy

There is limited data on the safety of allantoin in pregnancy. Use should be based on a risk-benefit assessment.

Breast-feeding

Limited data available, use with caution and consult a healthcare professional.

Storage

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

Formulations

• Topical cream
• Ointment
• Gel

Indications

• Skin burns and wounds
• Sunburn
• Acne
• Psoriasis
• Digestive disorders
• Constipation

Dosage

Children: For topical use, apply Aloe vera gel as needed on the affected area. For oral formulations, consult product-specific dosing recommendations tailored to children's needs.

Adults: For topical use, apply Aloe vera gel directly to the affected area as needed. For oral consumption, refer to specific product guidelines, as formulations vary widely.

Mechanism of action

The primary mechanism of action of Aloe vera involves its anti-inflammatory and immunomodulatory properties. The polysaccharides, such as acemannan, enhance immune function and promote wound healing. Aloe also exhibits antimicrobial activity, which can help in preventing infections in wounds. In the gastrointestinal tract, Aloe may exert a laxative effect by stimulating intestinal peristalsis and enhancing mucosal secretions.

Pharmacodynamics

Aloe vera gel has demonstrable effects on skin hydration, wound healing, and anti-inflammatory responses. Its polysaccharide content is responsible for its ability to retain moisture and promote cell proliferation and migration, essential processes in tissue repair. Additionally, Aloe has shown potential in modulating inflammatory cytokines, which may contribute to its soothing effects when applied topically.

Pharmacokinetics

Aloe vera is typically administered topically or orally. When applied to the skin, it is absorbed locally, facilitating its effects on the epidermis and dermis. Oral consumption of Aloe products leads to absorption of its active compounds in the gastrointestinal tract, where they may exert systemic effects. The half-life and metabolism of Aloe components can vary depending on the formulation and route of administration, with the laxative effects usually occurring within a few hours after oral intake.

Adverse effects

• Abdominal cramps
• Diarrhea
• Electrolyte imbalance
• Dehydration
• Allergic reactions

Interactions

• May interact with diuretics, increasing the risk of electrolyte imbalance
• May affect the absorption of other medications due to its laxative effects

Precautions

• Use with caution in individuals with gastrointestinal disorders
• Not recommended for long-term use due to potential for dependence
• Avoid in cases of known allergy to aloe or its components

Pregnancy

Aloe is not recommended during pregnancy due to potential uterine stimulation and risks of miscarriage.

Breast-feeding

Aloe should be avoided during breastfeeding as safety has not been established.

Storage

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

Formulations

• Aloe vera gel
• Aloe vera juice
• Aloe extracts in capsules or tablets

Indications

• General wellness support
• Anti-inflammatory effects
• Antioxidant activity
• Digestive aid
• Support for immune function

Dosage

Children: Paediatric dosing should be determined based on the specific extract and its intended use. Consultation with a healthcare provider is recommended for accurate dosing.

Adults: Dosage varies widely depending on the specific extract and formulation. It is essential to follow the manufacturer's instructions or consult a healthcare professional for appropriate dosing.

Mechanism of action

The mechanism of action of herbal extracts can vary significantly based on their constituents. Commonly, they exert their effects through multiple pathways including modulation of neurotransmitter systems, interference with inflammatory processes, or direct antioxidant activity. Some extracts may activate certain receptors or inhibit enzymes related to disease processes.

Pharmacodynamics

The pharmacodynamics of extracts is complex due to the presence of multiple active compounds which can have synergistic or antagonistic effects. These compounds may influence cellular signaling pathways, alter gene expression, or modulate immune response. The overall pharmacological profile is determined by the specific composition of the extract, its concentration, and the biological target it interacts with.

Pharmacokinetics

The pharmacokinetics of extracts involves absorption, distribution, metabolism, and excretion of the active compounds. Generally, herbal extracts are absorbed in the gastrointestinal tract, with bioavailability influenced by factors such as formulation, the presence of food, and individual metabolic differences. Compounds may undergo hepatic metabolism, and elimination can occur through urine or feces, depending on their chemical nature.

Pregnancy

Consult a healthcare professional before use, as the safety of the extract during pregnancy has not been established.

Breast-feeding

Consult a healthcare professional before use, as the safety of the extract during breastfeeding has not been established.

Storage

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

Indications

• Management of wounds
• Burn treatment
• Dental caries prevention
• Topical antiseptic
• Infection control in medical devices

Dosage

Children: Refer to BNF for Children for age-appropriate dosing recommendations.

Adults: Refer to BNF for specific dosing guidelines depending on the clinical context and formulation used.

Mechanism of action

Silver ions precipitate with chloride or phosphate anions and bind to proteins, leading to antibacterial effects by disrupting cell membranes. They can bind to peptidoglycans in bacterial cell walls, causing loss of structural integrity and function. Silver also binds to and oxidizes sulphydryl groups in enzymes, inhibiting metabolic processes. Additionally, silver ions may attach to bacterial DNA, inhibiting replication, and silver nanoparticles can generate reactive oxygen species, causing oxidative stress.

Pharmacodynamics

Silver exhibits broad-spectrum antimicrobial activity, effective against both Gram-positive and Gram-negative bacteria, including _Streptococcus mutans_, _Staphylococcus aureus_, and _Escherichia coli_. It has shown dose-dependent effects against methicillin-resistant Staphylococcus aureus (MRSA). Furthermore, silver compounds have demonstrated anti-inflammatory properties in models of skin inflammation and ulcerative colitis, suppressing pro-inflammatory cytokines and matrix metalloproteinases.

Pharmacokinetics

Silver does not have a well-defined pharmacokinetic profile due to its nature as a metal; however, it is known to bind extensively to proteins and tissues. Chronic exposure to silver can lead to accumulation and potential toxicity. The absorption and distribution of silver ions can vary based on the form of silver administered, with nanoparticles showing different properties compared to ionic silver.

Pregnancy

Safety during pregnancy has not been established. Use only if clearly needed.

Breast-feeding

Caution is advised as it is not known whether silver is excreted in human milk.

Storage

Store in a well-closed container, protected from light, at room temperature.

Formulations

• Silver nitrate
• Nanocrystalline silver

Indications

• Bacterial infections
• Urinary tract infections
• Respiratory tract infections
• Certain types of meningitis
• Toxoplasmosis

Dosage

Children: Refer to BNF for Children for specific dosing guidelines.

Adults: Refer to BNF for specific dosing guidelines.

Mechanism of action

Sulfadiazine acts as a competitive inhibitor of the bacterial enzyme dihydropteroate synthetase. This enzyme plays a key role in the metabolism of para-aminobenzoic acid (PABA), which is essential for folic acid synthesis in bacteria. By inhibiting this enzyme, sulfadiazine disrupts the production of folic acid, which is vital for bacterial growth and replication.

Pharmacodynamics

Sulfadiazine is classified as a sulfonamide antibiotic, which means it is bacteriostatic and acts by inhibiting bacterial growth. Sulfonamides are effective against a wide spectrum of bacteria, but resistance may develop. The mechanism involves the competitive inhibition of PABA in the folic acid metabolism pathway, which is critical for bacterial survival. While many bacterial strains are sensitive to sulfadiazine, some may show resistance, indicating that sensitivity to one sulfonamide generally implies sensitivity to others.

Pharmacokinetics

Sulfadiazine is well absorbed when taken orally, although parenteral administration is less common due to its alkaline properties that can irritate tissues. The drug distributes widely throughout body tissues and fluids, achieving high concentrations in pleural, peritoneal, synovial, and ocular fluids. Although it is not commonly used for meningitis treatment, it can reach therapeutic levels in the cerebrospinal fluid during meningeal infections. Its antibacterial effectiveness can be reduced in the presence of pus.

Contra-indications

• Hypersensitivity to sulfadiazine or other sulfonamides
• Severe liver or kidney impairment
• Pregnancy near term
• Infants under 2 months of age

Adverse effects

• Nausea
• Vomiting
• Skin rash
• Hematological reactions such as agranulocytosis or thrombocytopenia
• Hypersensitivity reactions including Stevens-Johnson syndrome
• Renal impairment

Interactions

• May enhance the effects of anticoagulants such as warfarin
• May interact with methotrexate, increasing toxicity
• May decrease the efficacy of oral contraceptives
• Probenecid may increase sulfonamide levels and risk of toxicity

Precautions

• Use with caution in patients with G6PD deficiency
• Monitor for signs of blood dyscrasias
• Ensure adequate hydration to prevent crystalluria
• Assess renal function before initiation

Pregnancy

Sulfadiazine should not be used during pregnancy, especially near term, due to potential risks to the fetus.

Breast-feeding

Sulfadiazine is excreted in breast milk. Caution is advised when administering to nursing mothers.

Storage

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

Formulations

• Tablets
• Oral suspension
• Injectable solution

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.

Mechanism of action

To elucidate the possible mechanism of initiation of lipid peroxidation in silver nitrate treated erythrocytes, the effect of AgNO3 on Hb catalyzed peroxidation of phospholipid liposomes was studied. Ag+ significantly increases the rate of Hb-catalyzed peroxidation. The inhibition of this effect by superoxide dismutase and catalase suggests that superoxide radical and H2O2 are involved. It was demonstrated also that Ag+ potentiates the Hb autoxidation and increases the binding of Hb to the erythrocyte membrane. Silver nitrate exhibits antiseptic, germicidal, astringent, and caustic or escharotic activity. These effects may result from silver ions readily combining with sulfhydryl, carboxyl, phosphate, amino, and other biologically important chemical groups. When silver ions interact with proteins, physical properties of the protein are usually altered; the protein may be denatured and precipitation usually occurs. Silver ions act on the surface of bacteria causing substantial changes in the cell wall and membrane. The germicidal activity of silver nitrate may be attributed to precipitation of bacterial proteins by liberated silver ions.

Mechanism of action

There is no well controlled data that can formally substantiate the method of action. However, ongoing studies suggest that there may exist a histological wound healing profile induced by allantoin in rats that leads to the amelioration and fastening of the reestablishment of normal skin. This facilitation of wound healing is supported by observations that wounds inflicted to rat subjects to which topical allantoin preparations were applied histologically demonstrated increased vasodilation, presence of inflammatory exudates, number of inflammatory cells, angiogenesis, fibroblast proliferation, and increased collagen deposition when compared to rat subjects with wounds that did not receive any allantoin administration.

Pharmacodynamics

There is no well controlled and appropriate data that can formally substantiate the pharmacodynamic properties of allantoin. Nevertheless, ongoing studies suggest that allantoin possesses moisturizing and keratolytic effects, as well as abilities to increase the water content of the extracellular matrix and enhance the desquamation of upper layers of dead skin cells, all of which are activities that can promote cell proliferation and facilitate wound healing.

Mechanism of action

The majority of released silver ions precipitate with chloride or phosphate anions or bind to albumins, macroglobulins, or tissue debris. While bound silver ions do not exert antibacterial actions, they may potentially play a role in silver toxicity in case of chronic exposure. Silver ions mediate antibacterial effects via disrupting the bacterial, fungal, and protozoal cell membranes; they bind to disulphide in membrane proteins, readily allowing penetration through the membranes and intracellular absorption via pinocytosis. They may also bind to negatively-charged peptidoglycans in the cell wall via electrostatic interactions, leading to disruption of membrane transport function and loss of structural integrity. Silver ions also bind to and oxidize sulphydryl groups (SH) in bacterial cytoplasmic enzymes to aberrate their function in metabolic processes. Silver nanoparticles may cause an increase in reactive oxygen species (ROS) inside the microbial cells leading to metal-induced oxidative stress and cell damage. They also modulate cellular signal system via inhibition of phosphorylation of essential bacterial proteins to eventually cause cell death. It is also reported that silver ions also attach to guanine in bacterial DNA, which inhibits DNA replication. While it is not fully understood, the mode of action of silver compounds in preventing and arresting dental caries is thought to involve inhibition of the demineralization process in addition to cytoplasmic and membrane function perturbation mentioned above. Silver compounds may directly interact with hydroxyapatite, a major tooth component. Light catalyzes the reduction of silver salts deposited in skin to metallic silver & it /is/ subsequently oxidized to silver sulfide; it is the deposition of the latter compound which accounts for the gray discoloration pathognomonic of argyria. /Silver and compounds/ Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. In this study, spherical nano-Ag (average diameter = 9.3 nm) particles were synthesized using a borohydride reduction method and the mode of their antibacterial action against E. coli was investigated by proteomic approaches (2-DE and MS identification), conducted in parallel to analyses involving solutions of Ag(+) ions. The proteomic data revealed that a short exposure of E. coli cells to antibacterial concentrations of nano-Ag resulted in an accumulation of envelope protein precursors, indicative of the dissipation of proton motive force. Consistent with these proteomic findings, nano-Ag were shown to destabilize the outer membrane, collapse the plasma membrane potential and deplete the levels of intracellular ATP. The mode of action of nano-Ag was also found to be similar to that of Ag(+) ions ... however, the effective concentrations of nano-Ag and Ag(+) ions were at nanomolar and micromolar levels, respectively. Nano-Ag appear to be an efficient physicochemical system conferring antimicrobial silver activities.

Pharmacodynamics

Silver exhibits a broad-spectrum antimicrobial activity. Silver ions were shown to mediate an effective antibacterial action against _Streptococcus mutans_, one of major bacteria present in the human oral cavity and one of etiological microorganism of dental caries. A study reported a dose-dependent antimicrobial activity of silver nanoparticles against MRSA and non-MRSA bacteria. Silver nanoparticles were also shown to mediate antibacterial activity against Gram-positive _S. aureus_ and Gram-negative _E. coli_ by inhibiting the growth. In experimental dinitrochlorobenzene-induced inflammatory models in porcine or murine skin, topical application of silver nitrate and nanocrystalline silver were shown to exert anti-inflammatory effects associated with lymphocyte apoptosis, decreased expression of pro-inflammatory cytokines, and reduced gelatinase activity. In a rat model of ulcerative colitis, orally or intracolonically administered nanocrystalline silver were shown to suppress matrix metalloproteinase (MMP-9), tumour necrosis factor (TNF), and interleukin-β (IL-β) and IL-12.

Mechanism of action

Sulfadiazine is a competitive inhibitor of the bacterial enzyme dihydropteroate synthetase. This enzyme is needed for the proper processing of para-aminobenzoic acid (PABA) which is essential for folic acid synthesis. The inhibited reaction is necessary in these organisms for the synthesis of folic acid.

Pharmacodynamics

Sulfadiazine is a sulfonamide antibiotic. The sulfonamides are synthetic bacteriostatic antibiotics with a wide spectrum against most gram-positive and many gram-negative organisms. However, many strains of an individual species may be resistant. Sulfonamides inhibit multiplication of bacteria by acting as competitive inhibitors of <i>p</i>-aminobenzoic acid in the folic acid metabolism cycle. Bacterial sensitivity is the same for the various sulfonamides, and resistance to one sulfonamide indicates resistance to all. Most sulfonamides are readily absorbed orally. However, parenteral administration is difficult, since the soluble sulfonamide salts are highly alkaline and irritating to the tissues. The sulfonamides are widely distributed throughout all tissues. High levels are achieved in pleural, peritoneal, synovial, and ocular fluids. Although these drugs are no longer used to treat meningitis, CSF levels are high in meningeal infections. Their antibacterial action is inhibited by pus.