ABSORICA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ABSORICA (ABSORICA).
Isotretinoin is a retinoid that binds to nuclear retinoic acid receptors (RARs) and retinoid X receptors (RXRs), modulating gene expression involved in cell differentiation, proliferation, and apoptosis. It reduces sebaceous gland size and sebum production, inhibits sebocyte differentiation, and has anti-inflammatory effects.
| Metabolism | Primarily metabolized by cytochrome P450 (CYP) enzymes, mainly CYP2C8, CYP2C9, CYP3A4, and CYP2B6. Major metabolites include 4-oxo-isotretinoin, tretinoin, and 4-oxo-tretinoin. Undergoes enterohepatic recirculation. |
| Excretion | Renal (approx. 65% as metabolites) and biliary (approx. 35% as metabolites). Less than 1% excreted unchanged. |
| Half-life | Terminal elimination half-life: 21-29 hours in adults; 33 hours in pediatric patients. Steady-state reached in 7-10 days. |
| Protein binding | 99.9% bound primarily to albumin. |
| Volume of Distribution | 50-200 L/kg (highly variable); extensive tissue distribution, particularly in skin, liver, and adipose tissue. |
| Bioavailability | Oral bioavailability is approximately 25% due to extensive first-pass metabolism; enhanced 1.5- to 2-fold when taken with a high-fat meal. |
| Onset of Action | Clinical improvement observed within 1-2 weeks of oral administration. |
| Duration of Action | Therapeutic effect persists for weeks to months after discontinuation; sebum production returns to pretreatment levels over 3-6 months. |
0.5-1 mg/kg/day orally in 2 divided doses for 15-20 weeks, then 0.1-0.5 mg/kg/day as maintenance.
| Dosage form | CAPSULE |
| Renal impairment | No adjustment recommended for mild-to-moderate renal impairment; use with caution in severe renal impairment (GFR <30 mL/min) with dose reduction of 50% or increased monitoring. |
| Liver impairment | Contraindicated in Child-Pugh Class B and C cirrhosis; use with caution in Child-Pugh Class A with initial dose reduction to 0.25 mg/kg/day. |
| Pediatric use | Not recommended for children under 12 years; for adolescents 12-17 years, same adult weight-based dosing (0.5-1 mg/kg/day) under specialist supervision. |
| Geriatric use | No specific dose adjustment required; monitor for adverse effects due to age-related decreased hepatic function and body composition changes. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ABSORICA (ABSORICA).
| Breastfeeding | Excretion into human milk is unknown but likely. M/P ratio not available. Due to potential for adverse effects in nursing infant, breastfeeding is contraindicated. |
| Teratogenic Risk | Isotretinoin is a known human teratogen with high risk of major fetal abnormalities including CNS, cardiovascular, and craniofacial defects if exposed during any trimester. Highest risk during first trimester; exposure contraindicated. |
| Fetal Monitoring |
■ FDA Black Box Warning
Isotretinoin is teratogenic and contraindicated in pregnancy. It is associated with an increased risk of severe birth defects, spontaneous abortion, and premature birth. Patients must be enrolled in the iPLEDGE risk management program.
| Serious Effects |
["Pregnancy or planned pregnancy (category X)","Hypersensitivity to isotretinoin or any component","Patients who are non-compliant with iPLEDGE program","Concurrent use of tetracyclines (increased risk of pseudotumor cerebri)","Elevated serum lipids (relative contraindication)","Hepatic or renal impairment (relative)"]
| Precautions | ["Teratogenicity: Absolute contraindication in pregnancy; effective contraception required (iPLEDGE program)","Psychiatric disorders: Suicidal ideation, depression, psychosis; monitor mood changes","Pseudotumor cerebri (benign intracranial hypertension): Risk with concomitant tetracycline use or vitamin A","Pancreatitis: Elevated triglycerides, acute pancreatitis; monitor lipids","Hepatotoxicity: Elevated liver enzymes; monitor LFTs","Inflammatory bowel disease: Exacerbation or new onset","Night blindness and decreased night vision","Increased risk of osteoporosis/fractures with long-term therapy","Photosensitivity: Avoid UV exposure","Skeletal hyperostosis with long-term use","Elevated triglycerides and cholesterol","Allergic reactions (angioedema, vasculitis)"] |
Loading safety data…
| Negative pregnancy test before initiation, monthly pregnancy tests during therapy, and one month after discontinuation. Use two forms of contraception one month before, during, and one month after treatment. |
| Fertility Effects | No evidence of permanent impairment; reversible menstrual irregularities reported. No effect on male fertility at therapeutic doses. |
| Food/Dietary | Take with a high-fat meal (e.g., 50g fat) to increase absorption. Avoid grapefruit juice (may increase isotretinoin levels). Limit alcohol due to hepatotoxicity risk. |
| Clinical Pearls | ABSORICA (isotretinoin) is a retinoid for severe recalcitrant nodular acne. Requires negative pregnancy test and two forms of contraception due to teratogenicity. Monitor lipids, liver function, and CBC monthly. Watch for mood changes and suicidal ideation. Avoid concomitant tetracyclines (increased pseudotumor cerebri risk). |
| Patient Advice | Do not become pregnant during treatment or for one month after stopping. · Use two effective forms of contraception simultaneously. · Do not donate blood during therapy and for 30 days after. · Avoid waxing, dermabrasion, or laser procedures due to skin fragility. · Report any mood changes, depression, or suicidal thoughts immediately. · Avoid alcohol and grapefruit juice as they may increase side effects. · Take with food, preferably with a high-fat meal to improve absorption. · Expect dry lips, skin, and eyes; use moisturizers and artificial tears. |