Isotretinoin
Isotretinoin. 13-cis isomer of retinoic acid. Reduces sebaceous-gland size + sebum production ~90%; induces keratinocyte differentiation… Oral half-life 20 h.
13-cis isomer of retinoic acid. Reduces sebaceous-gland size + sebum production ~90%; induces keratinocyte differentiation; anti-inflammatory. Only agent that produces durable acne remission (single course cures many). Severe teratogenicity (FDA iPLEDGE mandatory contraception for females of reproductive potential).
PK: the half-life of 20 h is REAL but belonged to the record other reference; the cited paper states 10 h and 16 h. V 35 L was the registry single most common value, shared by 31 records and identical to the resolver default, and was never measured — no intravenous formulation exists, so no true volume can. It is replaced by the published apparent 85 L with F pinned to 1. F 0.25 has no primary anywhere; candidate origins are a review or the cited paper own "25 DAYS" of dosing. ABSORPTION IS ZERO-ORDER WITH A 40-MINUTE LAG, plus enterohepatic recycling producing secondary and tertiary peaks and a 1.5 to 2-fold food effect, so a first-order rate is wrong in kind and ka 1.56 is dropped. The record correctly has NO effect compartment and must never acquire one: the sebaceous pharmacology develops over weeks to months, and an active 4-oxo metabolite exceeds the parent at steady state. A reference is a hypervitaminosis A review containing no kinetics.
Pharmacokinetics
- Oral — t½ 20 h · F 100% · Vd 85 L
Related compounds
- Vitamin A — contraindicated
- Tretinoin (topical) — caution
Sources: PMID:6575917, PMID:6957421, PMID:17224928, PMID:6582073