| name | Tretinoin (Retin-A) |
| classification | Topical retinoid, vitamin A derivative |
| pharmacokinetics | Tretinoin is readily absorbed through the skin. It is metabolized in the liver and excreted in the urine and bile. The peak effect is seen after several weeks of use, and it is considered to be slowly eliminated from the body. |
| suggested dosage | | male patient 25 70kg | | initial | Generally started with a low concentration (0.025%) once daily in the evening, for a few weeks to allow skin to adapt. | | escalation | Gradually increase the frequency and/or concentration (e.g., 0.05%, 0.1%) as tolerated, typically applied once daily before bedtime. |
| | important note | Dosage and frequency should be adjusted according to the individual patient's skin response, and should be guided by a physician. |
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| indications | | 1 | Acne vulgaris (mild to moderate) | | 2 | Actinic keratosis | | 3 | Photoaging (wrinkles, fine lines, age spots) | | 4 | Treatment of some types of skin cancer (e.g., superficial basal cell carcinoma, squamous cell carcinoma—typically in conjunction with other therapies) |
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| safety in pregnancy | Category X. Tretinoin is contraindicated during pregnancy. It is known to cause birth defects. |
| safety in breastfeeding | Limited data exists. It is prudent to avoid use during breastfeeding. |
| side effects | | 1 | Skin irritation (e.g., redness, dryness, burning, scaling, peeling) | | 2 | Photosensitivity (increased sun sensitivity): apply sunscreen every day | | 3 | Edema (swelling) | | 4 | Exacerbation of pre-existing skin conditions | | 5 | Transient hyperpigmentation (darkening of skin) | | 6 | Mild stinging or itching | | 7 | Possible temporary skin infections |
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| alternatives | | 1 | Adapalene (Differin) | | 2 | Azelaic acid | | 3 | Benzoyl peroxide | | 4 | Isotretinoin (Accutane) - Systemic retinoid (for severe acne, not typically a first-line alternative for topical use) | | 5 | Other topical retinoids (e.g., tretinoin gel, different concentrations) |
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| contraindications | | 1 | Known hypersensitivity to tretinoin or other retinoids | | 2 | Active skin infections or inflammation (unless specifically directed by a physician) | | 3 | Severe skin conditions (e.g., severe eczema, psoriasis) | | 4 | Pregnancy and breastfeeding |
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| interactions | Concurrent use with other topical retinoids may increase irritation. Use of strong topical corticosteroids may reduce the effectiveness of tretinoin. Avoid concurrent use of strong skin lighteners or other topical agents with photosensitizing properties. |
| warnings and precautions | | 1 | Start with low concentrations and use it only at night due to photosensitivity. | | 2 | Use sunscreen with a high SPF daily. | | 3 | Patients with a history of skin conditions (e.g. rosacea) should discuss use with a doctor. | | 4 | Discontinue use if significant skin irritation develops. |
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| additional information | | 1 | Tretinoin is available in various concentrations (e.g., 0.025%, 0.05%, 0.1%). | | 2 | Proper skin care is essential while using tretinoin (e.g., gentle cleansing, moisturizing) | | 3 | Results may vary depending on the individual and condition. Consistency is important for optimal results. |
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| patient specific considerations | | age | 25 years old | | weight | 70kg | | additional medical history | N/A (no additional medical history provided) |
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