DREZ POWDER

Indications

• Diagnostic imaging (CT scans, MRI)
• Angiography
• Urography
• Cholangiography
• Antiseptic use in wound care

Dosage

Children: Dosage for paediatric patients is determined based on the child's weight and the specific indication. Refer to the relevant pediatric guidelines for precise dosing recommendations.

Adults: Dosage of iodated compounds varies widely based on the procedure and the specific formulation used. Refer to specific product guidelines for appropriate dosing.

Mechanism of action

Iodated contrast media work primarily by absorbing X-rays more than the surrounding tissues, thereby enhancing the contrast in imaging studies. The iodine atoms in these compounds absorb X-rays due to their high atomic number, allowing for clearer images during procedures such as CT scans and angiography. Iodine also has antiseptic properties, disrupting the cell membranes of bacteria and inactivating proteins, leading to microbial death.

Pharmacodynamics

Iodated compounds exhibit a high osmolarity which can lead to transient cardiovascular effects. They can also cause a release of histamine, leading to potential allergic reactions. The antiseptic effect is due to the oxidative properties of iodine, which can denature proteins and disrupt nucleic acids in microorganisms.

Pharmacokinetics

Iodated contrast media are typically administered intravenously and distributed rapidly in the bloodstream. They are primarily excreted unchanged by the kidneys, and their elimination half-life can vary depending on the specific formulation used. The renal clearance of iodated compounds is essential, particularly in patients with impaired renal function, as it can lead to contrast-induced nephropathy.

Adverse effects

• Hypersensitivity reactions
• Thyroid dysfunction
• Gastrointestinal disturbances
• Metabolic acidosis
• Electrolyte imbalance

Interactions

• May interact with anticoagulants, increasing the risk of bleeding
• Can affect the efficacy of certain thyroid medications
• May alter the pharmacokinetics of other drugs metabolized by the liver

Precautions

• Caution in patients with pre-existing thyroid disease
• Use with caution in patients with renal impairment
• Monitor thyroid function tests during therapy
• Assess for allergies to iodinated contrast media

Pregnancy

Iodinated compounds are generally considered safe for use during pregnancy, but should be used only if clearly needed.

Breast-feeding

Iodinated compounds may be excreted in breast milk, caution is advised and nursing should be avoided if possible after administration.

Storage

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

Formulations

• Iodinated contrast agents
• Iodinated solutions for injection

Indications

• Bacterial vaginosis
• Clostridium difficile infection
• Pelvic inflammatory disease
• Anaerobic bacterial infections
• Giardiasis
• Amebiasis
• Helicobacter pylori eradication (as part of combination therapy)

Dosage

Children: Refer to the BNF for Children for appropriate dosing information for pediatric patients.

Adults: Refer to the relevant clinical guidelines or BNF for specific adult dosing recommendations based on the condition being treated.

Mechanism of action

Metronidazole is a nitroimidazole compound that, once reduced in anaerobic bacteria and protozoa, forms reactive intermediates that damage DNA, leading to cell death. The drug disrupts nucleic acid synthesis by interacting with DNA and inhibiting nucleic acid synthesis in susceptible organisms.

Pharmacodynamics

Metronidazole exhibits bactericidal activity against anaerobic bacteria and protozoa. Its effectiveness is attributed to its ability to penetrate the bacterial cell and disrupt DNA synthesis. It operates primarily in low-oxygen environments, which is characteristic of the infections it targets. The drug has a minimum inhibitory concentration (MIC) that varies among different organisms.

Pharmacokinetics

Metronidazole is well absorbed after oral administration, with peak plasma concentrations occurring within 1 to 2 hours. It has a large volume of distribution and is extensively metabolized in the liver, primarily through oxidation and glucuronidation. The elimination half-life is approximately 8 hours, and it is excreted in urine, with a significant proportion of the drug being eliminated in an active form.

Contra-indications

• Hypersensitivity to metronidazole or any of its components
• History of blood dyscrasia
• Severe hepatic impairment

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Metallic taste
• Headache
• Dizziness
• Peripheral neuropathy
• Seizures
• Disulfiram-like reaction with alcohol

Interactions

• Alcohol: may cause disulfiram-like reactions
• Warfarin: may enhance anticoagulant effect
• Lithium: may increase lithium levels
• Phenobarbital: may increase clearance of metronidazole

Precautions

• Use with caution in patients with liver disease
• Monitor for signs of peripheral neuropathy with prolonged use
• Avoid alcohol during and for at least 48 hours after treatment
• Assess for neurological side effects in patients on high doses or prolonged therapy

Pregnancy

Metronidazole is generally not recommended during the first trimester; potential risks to the fetus should be weighed against the benefits.

Breast-feeding

Metronidazole is excreted in breast milk; caution should be exercised and a decision should be made whether to discontinue breastfeeding or the drug.

Storage

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

Formulations

• Tablets
• Extended-release tablets
• Oral suspension
• Injectable solution
• Topical gel/cream

Indications

• Topical antiseptic for skin disinfection
• Preparation of skin prior to surgery
• Infection prevention in wound care
• Treatment of minor cuts and abrasions
• Oral rinse for dental antisepsis

Dosage

Children: Refer to specific product monographs or guidelines for paediatric dosing, as this can vary based on formulation and indication. Typically used topically; follow manufacturer's instructions.

Adults: Refer to specific product monographs or guidelines for adult dosing, as this can vary based on formulation and indication. Typically used topically; follow manufacturer's instructions.

Mechanism of action

Povidone's mechanism of action as an antiseptic primarily involves the release of iodine, which penetrates microbial cell walls and disrupts nucleic acid and protein synthesis. This leads to cell death and inhibition of microbial growth. The polymer itself also adsorbs to surfaces, providing a sustained antimicrobial effect.

Pharmacodynamics

Povidone exhibits broad-spectrum antimicrobial activity due to its ability to release iodine. The effectiveness of povidone-iodine is influenced by factors such as concentration, contact time, and the presence of organic matter. Its action is rapid, and it remains effective in the presence of blood and other body fluids, making it suitable for surgical and wound care applications.

Pharmacokinetics

Povidone is primarily administered topically, and its absorption through intact skin is minimal. When used as an antiseptic, it acts locally at the site of application. In cases where high concentrations are used, systemic absorption may occur, but it is generally considered low. The elimination half-life of iodine from the body is approximately 1-2 days, with renal excretion playing a significant role in the elimination of iodine.

Adverse effects

• Skin irritation
• Allergic reactions
• Staining of skin or mucous membranes
• Hypersensitivity reactions

Precautions

• Use with caution in patients with known allergies to iodine or iodine-containing products
• Avoid contact with eyes
• Not for use in deep puncture wounds or serious burns

Pregnancy

Considered safe for topical use during pregnancy, but consult with a healthcare provider before use.

Breast-feeding

Topical use is generally considered safe during breastfeeding; however, consult a healthcare provider.

Storage

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

Formulations

• Topical solution
• Ointment
• Swab sticks