MEDOX 12+12 COMBINATION PRODUCT TABLET

Indications

• Papulopustular rosacea
• Inflammatory acne vulgaris

Dosage

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

Adults: For papulopustular rosacea, apply daily for up to 4 months. The treatment course may be repeated; discontinue if no improvement is observed after 3 months. For inflammatory acne vulgaris, apply twice daily, reduced to once daily or alternate days if irritation occurs.

Mechanism of action

Nicotinamide exhibits anti-inflammatory effects by inhibiting the release of pro-inflammatory cytokines and enhancing the barrier function of the skin. It is also involved in the NAD salvage pathway, which is essential for maintaining cellular energy levels and promoting cell repair mechanisms. Additionally, nicotinamide contributes to the synthesis of coenzymes involved in metabolic processes, including the conversion of niacin into NAD+.

Pharmacodynamics

Nicotinamide is known for its ability to improve skin hydration and reduce transepidermal water loss. It has been shown to decrease the appearance of acne lesions and rosacea by modulating inflammatory responses and accelerating cell turnover. Its antioxidant properties also help to protect the skin from oxidative stress and UV damage.

Pharmacokinetics

When applied topically, nicotinamide is absorbed through the skin layers, with minimal systemic absorption. Its peak plasma concentrations are generally low, and the drug has a half-life that varies depending on the route of administration. The metabolism of nicotinamide occurs primarily in the liver, where it is converted into its active forms, including NAD+. The elimination route is via the kidneys, with metabolites excreted in urine.

Contra-indications

• Pregnancy
• Severe acne involving large areas
• Severe skin reactions

Adverse effects

• Sunburn
• Skin reactions (common or very common)
• Cheilitis
• Eyelid oedema
• Flushing
• Dry skin
• Eye irritation
• Photosensitivity reactions
• Transient skin pigmentation changes

Interactions

• Clindamycin
• Topical retinoids
• Abrasive cleaners
• Comedogenic cosmetics

Precautions

• Avoid exposure to UV light, including sunlight and sunlamps
• Wash hands immediately after use
• Avoid contact with eyes and mucous membranes
• Use moisturizers to reduce the risk of skin irritation
• Discontinue treatment if severe irritation occurs

Pregnancy

Avoid use during pregnancy due to potential risks, as limited information is available regarding toxicity.

Breast-feeding

Amount of drug in milk after topical application is probably too small to be harmful; ensure infant does not come in contact with treated areas.

Storage

Store at room temperature away from moisture and light.

Formulations

• Cream
• Gel

Indications

• Folate deficiency
• Megaloblastic anemia
• Prevention of neural tube defects in pregnancy
• Supplementation in patients on certain medications (e.g., methotrexate)

Dosage

Children: Refer to the BNF for Children for appropriate pa

Adults: Refer to specific guidelines or the BNF for appropriate adult dosing based on the indication.

Mechanism of action

Folate functions as a coenzyme in the conversion of homocysteine to methionine, a process that is vital for DNA synthesis and repair. It is involved in the one-carbon metabolism pathway, where it acts as a carrier of one-carbon units necessary for the synthesis of purines and thymidylate, thus supporting the production of nucleotides and DNA. This mechanism is particularly important in rapidly dividing cells.

Pharmacodynamics

Folate is critical for the formation of red blood cells and the proper functioning of the nervous system. It aids in the production of nucleic acids, which are essential for cell proliferation. Folate deficiency can lead to impaired DNA synthesis, resulting in megaloblastic anemia characterized by the presence of large, immature red blood cells in the bloodstream. Adequate folate levels are also associated with reduced risk of neural tube defects in developing fetuses.

Pharmacokinetics

Folate is absorbed in the proximal part of the small intestine, primarily in the jejunum, and is transported in the bloodstream bound to plasma proteins. It undergoes hepatic metabolism and is stored mainly in the liver. The elimination half-life varies, but dietary folate can be retained in the body for several weeks. Excess folate is excreted through the urine. The bioavailability of folate from food sources is lower compared to synthetic folic acid found in supplements.

Interactions

• folates+fluorouracil: Severe (increases risk of toxicity)
• folates+antiepileptics: Moderate (decreases concentration)
• folates+fosphenytoin: Moderate (decreases concentration)
• folates+phenobarbital: Moderate (decreases concentration)
• folates+phenytoin: Moderate (decreases concentration)
• folates+primidone: Moderate (decreases concentration)
• sulfasalazine+folates: Unknown (decreases absorption)

Pregnancy

Folate is essential for fetal development and is often recommended to prevent neural tube defects.

Breast-feeding

Folate is generally safe during breastfeeding, as it is important for both maternal and infant health.

Storage

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

Formulations

• Tablets
• Injection

Indications

• Vitamin deficiency
• Nutritional supplementation
• Prevention of certain diseases
• Supporting metabolic functions

Dosage

Children: Refer to specific guidelines for individual vitamins or consult a healthcare professional for personalized dosing recommendations.

Adults: Refer to specific guidelines for individual vitamins or consult a healthcare professional for personalized dosing recommendations.

Mechanism of action

Vitamins function primarily as coenzymes or precursors for enzyme cofactors in various metabolic pathways. For instance, B vitamins are involved in energy metabolism by assisting in the conversion of carbohydrates, fats, and proteins into energy. Vitamin C acts as an antioxidant, protecting cells from damage, and is also crucial for collagen synthesis. Fat-soluble vitamins like A are involved in vision and immune function, while vitamin D regulates calcium and phosphate metabolism.

Pharmacodynamics

Vitamins exert their effects by participating in biochemical reactions and influencing metabolic pathways. For example, vitamin A is vital for vision and immune response, while vitamin D is important for maintaining bone health through its role in calcium absorption. The effects of vitamins can vary significantly depending on their solubility, with water-soluble vitamins typically being excreted more readily than fat-soluble ones, which can accumulate in the body.

Pharmacokinetics

The absorption of vitamins varies; water-soluble vitamins are generally absorbed in the small intestine and excreted in urine, while fat-soluble vitamins require dietary fats for absorption and are stored in the liver and fatty tissues. The bioavailability of vitamins can be affected by dietary composition, age, and health status. Elimination half-lives also differ; for instance, vitamin C has a shorter half-life compared to vitamin A, which can persist in the body for longer periods.

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Constipation
• Headache
• Fatigue
• Allergic reactions

Interactions

• Fat-soluble vitamins (A, D, E, K) can accumulate and cause toxicity when taken in excess, especially with other supplements
• Certain medications (e.g., anticoagulants) may interact with vitamin K
• Vitamin C can enhance the absorption of iron supplements

Precautions

• Use caution in patients with kidney disease when taking vitamin D
• Monitor for signs of toxicity with high-dose vitamin supplementation
• Consider dietary sources of vitamins before recommending supplements

Pregnancy

Vitamins are generally considered safe during pregnancy when taken at recommended dosages. However, excessive intake, particularly of fat-soluble vitamins, should be avoided.

Breast-feeding

Most vitamins are safe during breastfeeding at recommended doses, but excessive amounts can affect breast milk composition.

Storage

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

Formulations

• Tablets
• Capsules
• Soft gels
• Powders
• Liquid solutions
• Chewable tablets