Isotretinoin

INDICATIONS AND USAGE Severe Recalcitrant Nodular Acne Isotretinoin capsules are indicated for the treatment of severe recalcitrant nodular acne. Nodules are inflammatory lesions with a diameter of 5 mm or greater. The nodules may become suppurative or hemorrhagic. "Severe," by definition, 2 means "many" as opposed to "few or several" nodules. Because of significant adverse effects associated with its use, isotretinoin capsules should be reserved for patients with severe nodular acne who are unresponsive to conventional therapy, including systemic antibiotics. In addition, isotretinoin capsules are indicated only for those patients who are not pregnant, because isotretinoin capsules can cause life-threatening birth defects (see Boxed CONTRAINDICATIONS AND WARNINGS ). A single course of therapy for 15 to 20 weeks has been shown to result in complete and prolonged remission of disease in many patients. 1,3,4 If a second course of therapy is needed, it should not be initiated until at least 8 weeks after completion of the first course, because experience has shown that patients may continue to improve while off isotretinoin capsules. The optimal interval before retreatment has not been defined for patients who have not completed skeletal growth (see WARNINGS: Skeletal: Bone Mineral Density , Hyperostosis , Premature Epiphyseal Closure ).

CLINICAL PHARMACOLOGY Isotretinoin is a retinoid, which when administered in pharmacologic dosages of 0.5 to 1 mg/kg/day (see DOSAGE AND ADMINISTRATION ), inhibits sebaceous gland function and keratinization. The exact mechanism of action of isotretinoin is unknown. Nodular Acne Clinical improvement in nodular acne patients occurs in association with a reduction in sebum secretion. The decrease in sebum secretion is temporary and is related to the dose and duration of treatment with isotretinoin capsules, and reflects a reduction in sebaceous gland size and an inhibition of sebaceous gland differentiation. 1 Pharmacokinetics Absorption Due to its high lipophilicity, oral absorption of isotretinoin is enhanced when given with a high-fat meal. In a crossover study, 74 healthy adult subjects received a single 80 mg oral dose (2 × 40 mg capsules) of isotretinoin under fasted and fed conditions. Both peak plasma concentration (C max ) and the total exposure (AUC) of isotretinoin were more than doubled following a standardized high-fat meal when compared with isotretinoin given under fasted conditions (see Table 2 ). The observed elimination half-life was unchanged. This lack of change in half-life suggests that food increases the bioavailability of isotretinoin without altering its disposition. The time to peak concentration (T max ) was also increased with food and may be related to a longer absorption phase. Therefore, isotretinoin should always be taken with food (see DOSAGE AND ADMINISTRATION ). Clinical studies have shown that there is no difference in the pharmacokinetics of isotretinoin between patients with nodular acne and healthy subjects with normal skin. Table 2 Pharmacokinetic Parameters of Isotretinoin Mean (%CV), N=74 Isotretinoin 2×40 mg Capsules AUC 0–∞ (ng∙hr/mL) C max (ng/mL) T max (hr) t 1/2 (hr) Fed Eating a standardized high-fat meal. 10,004 (22%) 862 (22%) 5.3 (77%) 21 (39%) Fasted 3,703 (46%) 301 (63%) 3.2 (56%) 21 (30%) Distribution Isotretinoin is more than 99.9% bound to plasma proteins, primarily albumin. Metabolism Following oral administration of isotretinoin, at least three metabolites have been identified in human plasma: 4- oxo -isotretinoin, retinoic acid (tretinoin), and 4- oxo -retinoic acid (4- oxo -tretinoin). Retinoic acid and 13- cis -retinoic acid are geometric isomers and show reversible interconversion. The administration of one isomer will give rise to the other. Isotretinoin is also irreversibly oxidized to 4- oxo -isotretinoin, which forms its geometric isomer 4- oxo -tretinoin. After a single 80 mg oral dose of isotretinoin to 74 healthy adult subjects, concurrent administration of food increased the extent of formation of all metabolites in plasma when compared to the extent of formation under fasted conditions. All of these metabolites possess retinoid activity that is in some in vitro models more than that of the parent isotretinoin. However, the clinical significance of these models is unknown. After

DOSAGE AND ADMINISTRATION Isotretinoin capsules should be administered with a meal (see PRECAUTIONS: Information for Patients ). The recommended dosage range for isotretinoin capsules are 0.5 to 1 mg/kg/day given in two divided doses with food for 15 to 20 weeks. In studies comparing 0.1, 0.5, and 1 mg/kg/day 8 , it was found that all dosages provided initial clearing of disease, but there was a greater need for retreatment with the lower dosages. During treatment, the dose may be adjusted according to response of the disease and/or the appearance of clinical side effects – some of which may be dose related. Adult patients whose disease is very severe with scarring or is primarily manifested on the trunk may require dose adjustments up to 2 mg/kg/day, as tolerated. Failure to take isotretinoin capsules with food will significantly decrease absorption. Before upward dose adjustments are made, the patients should be questioned about their compliance with food instructions. The safety of once daily dosing with isotretinoin capsules have not been established. Once daily dosing is not recommended. If the total nodule count has been reduced by more than 70% prior to completing 15 to 20 weeks of treatment, the drug may be discontinued. After a period of 2 months or more off therapy, and if warranted by persistent or recurring severe nodular acne, a second course of therapy may be initiated. The optimal interval before retreatment has not been defined for patients who have not completed skeletal growth. Long-term use of isotretinoin capsules, even in low doses, has not been studied, and is not recommended. It is important that isotretinoin capsules be given at the recommended doses for no longer than the recommended duration. The effect of long-term use of isotretinoin capsules on bone loss is unknown (see WARNINGS: Skeletal: Bone Mineral Density , Hyperostosis , and Premature Epiphyseal closure ). Contraceptive measures must be followed for any subsequent course of therapy (see PRECAUTIONS ). Table 4 Isotretinoin Dosing by Body Weight (Based on Administration With Food) Body Weight Total mg/day kilograms pounds 0.5 mg/kg 1 mg/kg 2 mg/kg See DOSAGE AND ADMINISTRATION: the recommended dosage range is 0.5 to 1 mg/kg/day. 40 88 20 40 80 50 110 25 50 100 60 132 30 60 120 70 154 35 70 140 80 176 40 80 160 90 198 45 90 180 100 220 50 100 200 INFORMATION FOR PHARMACISTS Access the iPLEDGE REMS system via the internet ( www.ipledgeprogram.com ), or telephone (1-866-495-0654) to obtain an authorization and the "do not dispense to patient after" date. Isotretinoin capsules must only be dispensed in no more than a 30-day supply. REFILLS REQUIRE A NEW PRESCRIPTION AND A NEW AUTHORIZATION FROM THE iPLEDGE SYSTEM. An isotretinoin capsules Medication Guide must be given to the patient each time isotretinoin capsules are dispensed, as required by law. This isotretinoin capsules Medication Guide is an important part of the risk management program for the patient.

ADVERSE REACTIONS Clinical Trials and Postmarketing Surveillance The adverse reactions listed below reflect the experience from investigational studies of isotretinoin , and the postmarketing experience. The relationship of some of these events to isotretinoin therapy is unknown. Many of the side effects and adverse reactions seen in patients receiving isotretinoin are similar to those described in patients taking very high doses of vitamin A (dryness of the skin and mucous membranes, e.g. of the lips, nasal passage, and eyes). Dose Relationship Cheilitis and hypertriglyceridemia are usually dose related. Most adverse reactions reported in clinical trials were reversible when therapy was discontinued; however, some persisted after cessation of therapy (see WARNINGS and ADVERSE REACTIONS ). Body as a Whole allergic reactions, including vasculitis, systemic hypersensitivity (see PRECAUTIONS: Hypersensitivity ), edema, fatigue, lymphadenopathy, weight loss Cardiovascular palpitation, tachycardia, vascular thrombotic disease, stroke Endocrine/Metabolic hypertriglyceridemia (see WARNINGS: Lipids ), alterations in blood sugar levels (see PRECAUTIONS: Laboratory Tests ). Gastrointestinal inflammatory bowel disease (see WARNINGS: Inflammatory Bowel Disease ), hepatitis (see WARNINGS: Hepatotoxicity ), pancreatitis (see WARNINGS: Lipids ), bleeding and inflammation of the gums, colitis, esophagitis/esophageal ulceration, ileitis, nausea, other nonspecific gastrointestinal symptoms. Hematologic allergic reactions (see PRECAUTIONS: Hypersensitivity ), anemia, thrombocytopenia, neutropenia, rare reports of agranulocytosis (see PRECAUTIONS: Information for Patients ). See PRECAUTIONS: Laboratory Tests for other hematological parameters. Musculoskeletal skeletal hyperostosis, calcification of tendons and ligaments, premature epiphyseal closure, decreases in bone mineral density (see WARNINGS: Skeletal ), musculoskeletal symptoms (sometimes severe) including back pain, myalgia, and arthralgia (see PRECAUTIONS: Information for Patients ), transient pain in the chest (see PRECAUTIONS: Information for Patients ), arthritis, tendonitis, other types of bone abnormalities, elevations of CPK/rare reports of rhabdomyolysis (see PRECAUTIONS: Laboratory Tests ). Neurological pseudotumor cerebri (see WARNINGS: Pseudotumor Cerebri ), dizziness, drowsiness, headache, insomnia, lethargy, malaise, nervousness, paresthesias, seizures, stroke, syncope, weakness. Psychiatric suicidal ideation, suicide attempts, suicide, depression, psychosis, aggression, violent behaviors (see WARNINGS: Psychiatric Disorders ), emotional instability. Of the patients reporting depression, some reported that the depression subsided with discontinuation of therapy and recurred with reinstitution of therapy. Reproductive System Abnormal menses. Respiratory bronchospasms (with or without a history of asthma), respiratory infection, voice alteration Skin and Appendages acne fulminans, alopecia (which in some cases persists), bruising, cheilitis (dry lips), dry mouth, dry nose, dry skin, epistaxis, eruptive xanthomas, 7 erythema multiforme, flushing, fragility of skin, hair abnormalities, hirsutism, hyperpigmentation and hypopigmentation, infections (including disseminated herpes simplex), nail dystrophy, paronychia, peeling of palms and soles, photoallergic/photosensitizing reactions, pruritus, pyogenic granuloma, rash (including facial erythema, seborrhea, and eczema), Stevens-Johnson syndrome, sunburn susceptibility increased, sweating, toxic epidermal necrolysis, urticaria, vasculitis (including Wegener's granulomatosis; see PRECAUTIONS: Hypersensitivity ), abnormal wound healing (delayed healing or exuberant granulation tissue with crusting; see PRECAUTIONS: Information for Patients ) Special Senses Hearing hearing impairment (see WARNINGS: Hearing Impairment ), tinnitus. Vision corneal opacities (see WARNINGS: Corneal Opacities ), decreased night vision which may persist (see

WARNINGS Psychiatric Disorders Isotretinoin capsules may cause depression, psychosis and, rarely, suicidal ideation, suicide attempts, suicide, and aggressive and/or violent behaviors. No mechanism of action has been established for these events (see ADVERSE REACTIONS: Psychiatric ). Prescribers should read the brochure, Recognizing Psychiatric Disorders in Adolescents and Young Adults: A Guide for Prescribers of Isotretinoin. Prescribers should be alert to the warning signs of psychiatric disorders to guide patients to receive the help they need. Therefore, prior to initiation of isotretinoin capsules therapy, patients and family members should be asked about any history of psychiatric disorder, and at each visit during therapy patients should be assessed for symptoms of depression, mood disturbance, psychosis, or aggression to determine if further evaluation may be necessary. Signs and symptoms of depression, as described in the brochure ("Recognizing Psychiatric Disorders in Adolescents and Young Adults"), include sad mood, hopelessness, feelings of guilt, worthlessness or helplessness, loss of pleasure or interest in activities, fatigue, difficulty concentrating, change in sleep pattern, change in weight or appetite, suicidal thoughts or attempts, restlessness, irritability, acting on dangerous impulses, and persistent physical symptoms unresponsive to treatment. Patients should stop isotretinoin capsules and the patient or a family member should promptly contact their prescriber if the patient develops depression, mood disturbance, psychosis, or aggression, without waiting until the next visit. Discontinuation of isotretinoin capsules therapy may be insufficient; further evaluation may be necessary. While such monitoring may be helpful, it may not detect all patients at risk. Patients may report mental health problems or family history of psychiatric disorders. These reports should be discussed with the patient and/or the patient's family. A referral to a mental health professional may be necessary. The physician should consider whether isotretinoin capsules therapy is appropriate in this setting; for some patients the risks may outweigh the benefits of isotretinoin capsules therapy. Pseudotumor Cerebri Isotretinoin capsules use has been associated with a number of cases of pseudotumor cerebri (benign intracranial hypertension), some of which involved concomitant use of tetracyclines. Concomitant treatment with tetracyclines should therefore be avoided. Early signs and symptoms of pseudotumor cerebri include papilledema, headache, nausea and vomiting, and visual disturbances. Patients with these symptoms should be screened for papilledema and, if present, they should be told to discontinue isotretinoin capsules immediately and be referred to a neurologist for further diagnosis and care (see ADVERSE REACTIONS: Neurological ). Serious Skin Reactions There have been post-marketing reports of erythema multiforme and severe skin reactions [e.g., Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN)] associated with isotretinoin use. These events may be serious and result in death, life-threatening events, hospitalization, or disability. Patients should be monitored closely for severe skin reactions, and discontinuation of isotretinoin capsules should be considered if warranted. Pancreatitis Acute pancreatitis has been reported in patients with either elevated or normal serum triglyceride levels. In rare instances, fatal hemorrhagic pancreatitis has been reported. Isotretinoin capsules should be stopped if hypertriglyceridemia cannot be controlled at an acceptable level or if symptoms of pancreatitis occur. Lipids Elevations of serum triglycerides in excess of 800 mg/dL have been reported in patients treated with isotretinoin capsules. Marked elevations of serum triglycerides were reported in approximately 25% of patients receiving isotretinoin capsules in clinical trials. In addition, approximately 15% developed a d

CONTRAINDICATIONS Pregnancy Category X See Boxed CONTRAINDICATIONS AND WARNINGS . Allergic Reactions Isotretinoin capsules are contraindicated in patients who are hypersensitive to this medication or to any of its components (see PRECAUTIONS: Hypersensitivity ).

OVERDOSAGE The oral LD 50 of isotretinoin is greater than 4000 mg/kg in rats and mice (>600 times the recommended clinical dose of 1 mg/kg/day after normalization of the rat dose for total body surface area and >300 times the recommended clinical dose of 1 mg/kg/day after normalization of the mouse dose for total body surface area) and is approximately 1960 mg/kg in rabbits (653 times the recommended clinical dose of 1 mg/kg/day after normalization for total body surface area). In humans, overdosage has been associated with vomiting, facial flushing, cheilosis, abdominal pain, headache, dizziness, and ataxia. These symptoms quickly resolve without apparent residual effects. Isotretinoin capsules cause life-threatening birth defects at any dosage (see Boxed CONTRAINDICATIONS AND WARNINGS ). Patients who can become pregnant who present with isotretinoin overdose must be evaluated for pregnancy. Patients who are pregnant should receive counseling about the risks to the fetus, as described in the Boxed CONTRAINDICATIONS AND WARNINGS . Non-pregnant patients must be warned to avoid pregnancy for at least one month and receive contraceptive counseling as described in PRECAUTIONS . Educational materials for such patients can be obtained by calling the manufacturer. Because an overdose would be expected to result in higher levels of isotretinoin in semen than found during a normal treatment course, male patients should use a condom, or avoid reproductive sexual activity with a patient who is or might become pregnant, for one month after the overdose. All patients with isotretinoin overdose should not donate blood for at least one month.