Farmacologia de la piel y ATB de aplicacion local

Summary

This medical lecture by Dr. Federico José Turné delves into dermatological pharmacology, focusing on skin ecology and local antibiotic application. It explores the skin's structure, absorption mechanisms, and the role of excipients in topical formulations. The lecture also discusses acne treatment with retinoids and antibiotics, highlighting their mechanisms and side effects. A clinical case of impetigo in a pediatric patient is presented, illustrating the diagnostic process and treatment options, emphasizing the importance of topical and systemic antibiotics in managing skin infections.

Takeaways

• 😀 The speaker, Dr. Federico José Turné, is a physician and lecturer who has been teaching about macrolides and tetracyclines for two years.
• 📚 The class is divided into two parts: the first covers general dermatological pharmacology, including the structure of the skin and how topical medications work.
• 🧪 The skin is composed of three layers: the epidermis, dermis, and hypodermis, with the epidermis containing immune cells and melanocytes that give skin its color.
• 💊 Topical medications must have certain characteristics for effective absorption, such as being of low molecular weight, having good solubility in oil and water, and a high partition coefficient.
• 🧴 Excipients or vehicles in dermatological medications can include antioxidants, antimicrobials, stabilizers, and emulsifiers, and are classified based on their physical state and water content.
• 🚫 Ointments, which have occlusive properties, are not recommended for infected skin due to the risk of bacterial colonization and replication.
• 🧪 The second part of the class focuses on local antibiotics, including their use in treating skin conditions like acne, where they target specific bacteria and have anti-inflammatory properties.
• 🌞 Retinoids, used for treating acne and other skin conditions, work by binding to nuclear receptors and activating gene transcription, with effects such as reducing sebaceous gland size and normalizing keratinization patterns.
• ☀️ Topical retinoids like tretinoin and adapalene are commonly used for acne, with tretinoin requiring nighttime application due to photosensitivity.
• ⚠️ Isotretinoin, a systemic retinoid, has various side effects and requires monitoring, including potential birth defects, making it contraindicated during pregnancy and breastfeeding.
• 🛑 The case study presented involves a 4-year-old boy with skin lesions, suggesting a possible bacterial infection that may be treated with topical antibiotics like mupirocin or fusidic acid, depending on the causative bacteria.

Q & A

What is the main focus of the lecture given by Federico José Turné?

The lecture focuses on dermatological pharmacology, specifically discussing the pharmacology of the skin, local antibiotic application, and treatments for conditions like acne.

What are the two main parts of the class that Federico José Turné mentions?

The class is divided into two parts: the first part discusses general aspects of skin ecology and how medications act locally on the skin, and the second part is about local antibiotic application, with a focus on the skin and acne treatment.

What are the three layers that make up the skin structure?

The skin structure is composed of three layers: the epidermis, dermis, and hypodermis.

What are the two main mechanisms of percutaneous absorption mentioned in the script?

The two main mechanisms of percutaneous absorption are intercellular, where the substance does not pass through the cell but evades the cell boundaries, and transcellular, where the substance passes through the cells.

What characteristics should a drug have to effectively act on the skin?

For a drug to effectively act on the skin, it should have low molecular weight, appropriate solubility in oil and water, and a high partition coefficient, which indicates the ability to separate from its vehicle or excipient.

What are the purposes of excipients or vehicles in dermatological medications?

Excipients or vehicles in dermatological medications serve therapeutic and cosmetic purposes, and they can also contain antioxidants, antimicrobials, stabilizers, and emulsifiers.

What are the differences between ointments, creams, and lotions as mentioned in the script?

Ointments are occlusive, which means they prevent water evaporation and thus soften and hydrate the skin but are not recommended for infections. Creams have a higher water content than ointments and are suitable for local application on the skin or certain mucous membranes. Lotions are liquid preparations typically used for application on the skin.

What is the role of retinoids in treating acne?

Retinoids play a crucial role in treating acne by reducing the size of sebaceous glands, regulating cell proliferation, normalizing keratinization patterns, and having anti-inflammatory effects. They are also involved in immune defense.

What are the different generations of retinoids mentioned in the script?

The script mentions first-generation retinoids like retinol, tretinoin, and isotretinoin; second-generation aromatic retinoids like acitretin and methoxsalen; third-generation retinoids like tazarotene, bexarotene, and adapalene; and fourth-generation retinoids like trifarotene.

What are the systemic and topical administration routes for retinoids?

Retinoids can be administered topically as gels and creams, with tretinoin and adapalene being commonly used in Argentina. Systemically, isotretinoin is used for more severe cases of acne.

What are the potential adverse effects of isotretinoin mentioned in the script?

Potential adverse effects of isotretinoin include dry skin, photosensitivity, cheilitis, erythema, pruritus, myalgia, arthralgia, headaches, depression, hyperlipidemia, and teratogenic effects such as craniofacial, nervous system, and cardiac defects, as well as cleft palate.