Isotretinoin

Absorption

Patients reach a maximum concentration of 74-511ng/mL after 1-4 hours following a 100mg oral dose. Isotretinoin is better absorbed with a high fat meal and bioavailability may change from one brand to another.
Following a 40mg oral dose, fasted subjects reached a maximum concentration of 314ng/mL in 2.9 hours with an area under the curve of 4055ng/mL*hr. Subjects given a high fat meal and a 40mg oral doses reached a maximum concentration of 395ng/mL in 6.4 hours with an area under the curve of 6095ng/mL*mL.

Toxicity

Patients experiencing an overdose may present with vomiting, facial flushing, cheilosis, abdominal pain, headache, dizziness, and ataxia. These symptoms may rapidly resolve. Generally no treatment is required for these overdoses.
The oral lowest dose causing toxic effect (TDLO) for children is 30mg/kg/21W, oral TDLO for men is 24mg/kg/4W, oral TDLO for women is 56mg/kg/8W. The intraperitoneal LD50 for rats is 901mg/kg, oral LD50 for mice is 3389mg/kg, oral LD50 for rats is >4000mg/kg.
Isotretinoin is associated with major congenital malformations, spontaneous abortion, and premature birth. It is unknown if isotretinoin is expressed in breast milk but due to the associated hazards a decision should be made to either stop nursing or stop taking isotretinoin.
In animal studies, isotretinoin was associated with an increased risk of pheochromocytoma and adrenal medullary hyperplasia at doses above the recommended clinical dose. Isotretinoin was negative for the Ames test of mutagenicity once and weakly positive a second time. It has not been shown to be clastogenic. A study in dogs noted testicular atrophy after doses of 10-30 times the recommended clinical dose for 30 weeks. In trials with men there were no effects seen on sperm count, motility, morphology, ejaculate volume, and seminal plasma fructose.

Description

Isotretinoin is the 9-cis isomer of retinoic acid, a close relative of retinol, or vitamin A. It was originally developed to treat cystic acne, and today this is still its primary use despite several more modern applications of the drug, including a treatment for pancreatic and brain cancers. First shown to be an effective treatment for acne in 1982, its development stemmed from advances in knowledge of the effects of vitamin A to reduce or eliminate sebum production. Since that time, however, several instances of deleterious effects became well known, most notably birth defects arising from the use of isotretinoin.

The Uses of Isotretinoin

isotretinoin is a retinoid derivative with improved bioavailability and percutaneous absorption for acne treatment products. Presently being studied in conjuction with the treatment of photoaged skin.

What are the applications of Application

13-cis-Retinoic acid is a vitamin A analog that inhibits cell proliferation

Background

Isotretinoin is a retinoid derivative of vitamin A used in the treatment of severe recalcitrant acne. It was most widely marketed under the brand name Accutane, which has since been discontinued. Isotretinoin is associated with major risks in pregnancy and is therefore only available under the iPLEDGE program in the United States. The first isotretinoin-containing product was FDA approved on 7 May 1982.

Indications

Isotretinoin is indicated to treat severe recalcitrant nodular acne and patients ≥12 years enrolled in the iPLEDGE program.

Pharmacokinetics

The pharmacodynamics of isotretinoin are poorly understood.

Metabolism

Isotretinoin, or 13-cis-retinoic acid can undergo reversible cis-trans isomerization to all-trans-retinoic acid. Isotretinoin undergoes 4-hydroxylation to 4-hydroxy-13-cis-retinoic acid, which is oxidized to the main metabolite 4-oxo-13-cis-retinoic acid.. All-trans-retinoic acid undergoes 4-hydroxylation to 4-hydroxy-all-trans-retinoic acid, which is oxidized to 4-oxo-all-trans-retinoic acid. 4-oxo-13-cis-retinoic acid can undergo reversible cis-trans isomerization to 4-oxo-all-trans-retinoic acid.