Isotretinoin

Isotretinoin is used for: Acne

Oral Severe, Recalcitrant Nodular Acne Severe nodular acne unresponsive to conventional therapy, including systemic antibiotics Adult: 0.5-1 mg/kg/day PO divided BID for 15-20 weeks Dose up to 2 mg/kg/day (as tolerated) if disease is very severe with scarring or is primarily manifested on the trunk Hepatic impairment: Contraindicated.

Severe, Recalcitrant Nodular Acne Severe nodular acne unresponsive to conventional therapy, including systemic antibiotics <12 years: Safety and efficacy not established >12 years: 0.5-1 mg/kg/day PO divided BID for 15-20 weeks Dose up to 2 mg/kg/day (as tolerated) if disease is very severe with scarring or is primarily manifested on the trunk

Renal impairment: Severe: Reduce initial dose (e.g. 10 mg daily), then gradually increase to 1 mg/kg as necessary.

Should be taken with food.

Pregnancy, lactation.

Preexisting or predisposition to hypertriglyceridaemia (e.g. DM, obesity or increased alcohol intake). Monitor triglyceride levels. Monitor blood lipids and LFTs at wkly or bi-wkly intervals. Monitor blood glucose in known or suspected DM patients. Genetic predisposition for age-related osteoporosis, history of childhood osteoporosis, osteomalacia or other bone metabolism disorders. Anorexia nervosa. History of psychiatric disorder. May impair night vision. Avoid wax epilation and skin resurfacing procedures for at least 6 mth. Avoid prolonged exposure to UV light or sunlight. Discontinue if hearing impairment, abdominal pain, rectal bleeding, severe diarrhoea or adverse ocular effects occur. Patient should not donate blood during therapy and for at least 1 mth following drug discontinuation. Lactation: Unknown whether distributed into breast milk; because of potential for serious adverse reactions in nursing infants, do not administer to women who are breastfeeding

Preganacy Therapy is contraindicated during pregnancy; it can cause fetal harm when administered to a pregnant patient; there is increased risk of major congenital malformations, spontaneous abortions, and premature births following isotretinoin exposure during pregnancy in humans If drug is used during pregnancy, or if patient becomes pregnant while receiving therapy, patient should be apprised of potential hazard to a fetus If pregnancy occurs during treatment of patient receiving therapy, it must be discontinued immediately and patient should be referred to Obstetrician-Gynecologist experienced in reproductive toxicity for further evaluation and counseling If a pregnancy occurs during treatment, discontinue therapy immediately and refer patient to obstetrician/gynecologist experienced in reproductive toxicity for further evaluation and counseling Contraception Patients who can become pregnant must use 2 forms of contraception simultaneously, at least 1 of which must be a primary form, for at least 1 month prior to initiation of therapy, during therapy, and for 1 month after discontinuing therapy; however, 2 forms of contraception is not required if the patient commits to continuous abstinence from not having any sexual contact with a partner which may result in pregnancy, has undergone a hysterectomy or bilateral oophorectomy, or has been medically confirmed to be post- menopausal Micro-dosed progesterone preparations (“minipills” that do not contain an estrogen) are an inadequate method of contraception during therapy. Any birth control method can fail; there have been reports of pregnancy from patients who have used combination oral contraceptives, as well as contraceptive vaginal systems, vaginal inserts, transdermal systems, and injections; these pregnancies occurred while taking isotretinoin It is critically important that patients who can become pregnant use 2 methods of contraception simultaneously Lactation There are no data on either animal or human milk, effects on breastfed infant, or on milk production; because of potential for serious adverse reactions in nursing infants from isotretinoin, advise patients that breastfeeding is not recommended during treatment and for at least 8 days after the last dose

Additive toxicity with vitamin A or its derivatives. Decreased efficacy of microdosed progesterone (use 2 forms of contraception). May increase risk of bone loss with phenytoin. May increase risk of osteoporosis with systemic corticosteroids. Reduces plasma levels of carbamazepine. Potentially Fatal: Increased risk of pseudotumor cerebri with tetracyclines.

Side effects of Isotretinoin : >10% Cheilitis (90%), Xerosis, Xerostomia, Dry nose, Epistaxis, Pruritus, Conjunctivitis (including blepharoconjunctivitis) (40%), Irritation (40%), Increased erythrocyte sedimentation rates (40%), Thinning of hair (which has persisted in rare instances), Palmoplantar desquamation, Skin fragility, Skin infections (eg, paronychial infections), Rash (including erythema, seborrhea, eczema), photosensitivity, Hypertriglyceridemia (25%), Bone or joint pain, Generalized muscle aches, Arthralgia, Decreased HDLs (15%), Increased LFTs (15%), Increased CPK (12-24%), Decreased hemoglobin concentration and hematocrit, Decreased erythrocyte and leukocyte counts, Increased platelet count 1-10% Decreased bone mineral density (8.8%), Premature epiphyseal closure (3%) Frequency Not Defined Lethargy, Fatigue, Headache, Anorexia, Nausea, Vomiting, Increased appetite, Thirst Potentially Fatal: Anaphylaxis. Haemorrhagic pancreatitis.

Isotretinoin is a synthetic retinoid which reduces sebaceous gland size and sebum production. It also regulates cell proliferation and differentiation.