Isotretinoin


Concise Prescribing Info
Indications/Uses
Acne.
Dosage/Direction for Use
Adult : PO Initial: 0.5 mg/kg/day in single or 2 divided doses, increased to 1 mg/kg/day as needed. Usual duration: 16-24 wk. Ensure a 2-mth drug-free interval if a 2nd course is needed. Topical As 0.05% gel: Apply 1-2 times/day.
Dosage Details
Oral
Acne
Adult: Initially, 0.5 mg/kg daily in single or 2 divided doses, increased to 1 mg/kg daily if necessary. Usual duration of treatment: 16-24 wk. May repeat treatment course after at least 8 wk if relapse after first course.
Child: ≥12 yr Same as adult dose.

Topical/Cutaneous
Acne
Adult: As 0.05% gel: Apply sparingly once or twice daily. Effect is observed w/in 6-8 wk of treatment.
Renal Impairment
Oral:
Severe: Reduce initial dose (e.g. 10 mg daily), then gradually increase to 1 mg/kg as necessary.
Hepatic Impairment
Oral:
Contraindicated.
Administration
Should be taken with food.
Contraindications
Hypervitaminosis A, hyperlipidaemia. Hepatic impairment. Pregnancy and lactation. Concomitant admin of tetracycylines.
Special Precautions
Women of childbearing potential; anorexia nervosa. History of photoallergy, psychiatric disorder (e.g. depression); pre-existing or predisposition to hypertriglyceridaemia (e.g. DM, obesity or increased alcohol intake). Genetic predisposition for age-related osteoporosis, history of childhood osteoporosis, osteomalacia or other bone metabolism disorders. Not intended for the treatment of prepubertal acne. Severe renal impairment.
Adverse Reactions
Erythema, skin exfoliation, stinging sensation, pruritus, irritation, tenderness, dry skin, hirsutism, photosensitivity, skin pigmentation, paronychia, nail dystrophy, pyogenic granuloma, increased sweating, corneal opacities, visual disturbances, headache, nausea and vomiting, arthralgia, myalgia, back pain, intracranial HTN, hyperostosis and calcinosis. Elevation of serum triglycerides, LFTs, ESR and blood glucose. Mood changes, psychotic symptoms, depression and suicidal behaviour.
Potentially Fatal: Haemorrhagic pancreatitis, severe skin reactions (e.g. Stevens-Johnson syndrome, toxic epidermal necrolysis).
Patient Counseling Information
Avoid exposure to natural or artificial sunlight. Avoid blood donation during therapy and for at least 1 mth following drug discontinuation. This drug may cause dizziness, drowsiness and visual disturbances, if affected, do not drive or operate machinery.
MonitoringParameters
Monitor plasma lipid, glucose levels regularly (esp in diabetic patients). Perform LFTs; pregnancy test.
Drug Interactions
Additive adverse effects w/ vit A or its derivatives. Decreased efficacy of microdosed progesterone (use 2 forms of contraception).Increased risk of local irritation w/ topical keratolytic or exfoliative anti-acne agents. Oxidising agents (e.g. benzoyl peroxide) may reduce the efficacy of topical isotretinoin.
Potentially Fatal: Development of benign intracranial HTN w/ tetracycline.
Food Interaction
Increased bioavailability w/ food or milk.
Action
Description: Isotretinoin is a synthetic retinoid which reduces sebaceous gland size and inhibits sebum production. It also regulates cell proliferation and differentiation and has dermal anti-inflammatory effect.
Pharmacokinetics:
Absorption: Absorbed from the GI tract (oral); minimal systemic absorption (topical). Increased bioavailability if taken w/ milk or food. Time to peak plasma concentrations: 1-4 hr (oral).
Distribution: Protein-binding: 99.9%, mainly to albumin.
Metabolism: Metabolised in the liver to 4-oxo-isotretinoin by CYP isoenzymes (mainly CYP2C8, CYP2C9, CYP3A4 and CYP2B6); also undergoes some isomerisation to tretinoin.
Excretion: Via urine as metabolites and faeces, mainly as unchanged drug. Terminal elimination half-life: 21 hr (isotretinoin); 21-24 hr (4-oxo metabolite).
Chemical Structure

Chemical Structure Image
Isotretinoin

Source: National Center for Biotechnology Information. PubChem Database. Isotretinoin, CID=5282379, https://pubchem.ncbi.nlm.nih.gov/compound/Isotretinoin (accessed on Jan. 21, 2020)

Storage
Store between 20-25°C. Protect from light.
ATC Classification
D10BA01 - isotretinoin ; Belongs to the class of systemic retinoid preparations used in the treatment of acne.
D10AD04 - isotretinoin ; Belongs to the class of topical retinoid preparations used in the treatment of acne.
References
Anon. Isotretinoin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 06/06/2016.

Buckingham R (ed). Isotretinoin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 06/06/2016.

Claravis Capsule, Liquid Filled (Teva Pharmaceuticals USA, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 06/06/2016.

Joint Formulary Committee. Isotretinoin. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 06/06/2016.

McEvoy GK, Snow EK, Miller J et al (eds). Isotretinoin. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 06/06/2016.

Disclaimer: This information is independently developed by MIMS based on Isotretinoin from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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