## **1. Introduction to 니메겐 (Nimegen)** **니메겐** (active ingredient: **isotretinoin**, isotretinoin 10 mg or 20 mg) is an oral medication primarily used to treat severe, nodulocystic acne that is resistant to conventional therapies. It is a retinoid derivative of Vitamin A and exerts potent effects on sebaceous gland function. --- ## **2. Mechanism of Action** Isotretinoin has multiple modes of action: - **Sebum Reduction**: Dramatically reduces sebum production by decreasing sebaceous gland size and activity. - **Normalization of Keratinization**: Prevents abnormal keratinization, thereby reducing follicular plugging and comedone formation. - **Anti-inflammatory Action**: Exhibits indirect anti-inflammatory properties, reducing inflammatory acne lesions. - **Reduction of P. acnes colonization**: Decreases the skin’s bacterial flora, particularly _Cutibacterium acnes_. --- ## **3. Clinical Indications** The primary indication for **니메겐** is: - **Severe nodulocystic acne** - **Acne resistant** to topical retinoids, antibiotics, benzoyl peroxide, or hormonal therapy Additionally, low-dose regimens (off-label use) may occasionally be prescribed for moderate acne or persistent acne unresponsive to other treatments. --- ## **4. Dosage and Administration** - Standard dose: **0.5 to 1 mg/kg/day**, usually starting low (0.5 mg/kg/day) and gradually increased depending on tolerability and therapeutic response. - Cumulative dose: Optimal therapeutic cumulative dose is **120-150 mg/kg** total over the treatment duration (generally **4–6 months**). - Administration with food enhances absorption, particularly fatty meals. --- ## **5. Contraindications and Precautions** ### **Absolute contraindications**: - **Pregnancy**: Highly teratogenic (Category X) - Lactation - Severe hepatic insufficiency - Hypervitaminosis A - Hypersensitivity to isotretinoin or excipients ### **Precautions**: - Psychiatric disorders (risk of depression) - Lipid metabolism disorders (hypertriglyceridemia, hypercholesterolemia) - Liver function impairment - Diabetes mellitus (potential glucose metabolism changes) --- ## **6. Side Effects** **Common Side Effects**: - Dryness: Cheilitis (dry lips), xerosis (dry skin), dry eyes, dry nasal mucosa, epistaxis - Photosensitivity: increased sun sensitivity - Initial worsening of acne ("flare-up") **Less Common but Serious Side Effects**: - Psychiatric: depression, anxiety, mood changes (rare but significant) - Hepatotoxicity: elevated liver enzymes - Hyperlipidemia: elevated triglycerides and cholesterol levels - Musculoskeletal: myalgia, arthralgia, and rarely skeletal hyperostosis --- ## **7. Monitoring and Patient Management** Regular monitoring is essential: - **Baseline tests**: - Complete blood count (CBC) - Liver function tests (LFTs): ALT, AST, bilirubin - Lipid profile: cholesterol and triglycerides - Pregnancy test for female patients (mandatory due to teratogenicity) - **Follow-up schedule**: - Monthly clinical assessment - Repeat blood tests monthly (initial 1–2 months), then every 1–2 months thereafter. - Patients must avoid pregnancy during therapy and at least **one month** after cessation. --- ## **8. Important Patient Counseling Points** - Inform patients clearly about severe birth defects risk and the necessity of reliable contraception. - Advise patients about dryness management: moisturizer, lip balm, artificial tears, nasal lubricants. - Sunscreen and sun protection are essential. - Alcohol intake reduction advised due to hepatotoxicity risk. - Patients should immediately report mood changes, suicidal thoughts, severe headache, or visual disturbances. --- ## **9. Relationship to Hair Transplantation** Isotretinoin (**니메겐**) is important in dermatology practice, but its relevance to hair transplantation is indirect: - Patients with severe acne often have concerns about skin scarring or skin quality near donor or recipient areas. Improving acne prior to surgery can enhance patient satisfaction. - **Timing**: Due to delayed wound healing, elective surgical procedures (like hair transplantation) are usually postponed until at least **6–12 months** after cessation of isotretinoin treatment. ---