Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Isotretinoin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2001

Safety of a new micronized formulation of isotretinoin in patients with severe recalcitrant nodular acne: A randomized trial comparing micronized isotretinoin with standard isotretinoin.

BACKGROUND: Isotretinoin is a very effective drug for treating severe recalcitrant nodular acne. A new micronized formulation of isotretinoin has been shown to be clinically equivalent to standard isotretinoin with improved bioavailability and minimal food effect. The safety profile of the micronized formulation has not been described previously. OBJECTIVE: The objective of this article is to report the incidence and intensity of adverse events found in a comparative, double-blind efficacy study that showed clinical equivalence of the new micronized formulation of isotretinoin and the standard isotretinoin formulation (Accutane). METHODS: Six hundred patients with severe recalcitrant nodular acne were treated with micronized isotretinoin (n = 300) under fasted conditions or standard isotretinoin (n = 300) under fed conditions. One cohort received single daily doses of 0.4 mg/kg of micronized isotretinoin without food and the other cohort received 1.0 mg/kg per day of standard isotretinoin in two divided doses with food. Adverse events were monitored during 20 weeks of drug therapy. RESULTS: The proportion of adverse events in most body systems was generally lower in patients receiving micronized isotretinoin than in those receiving standard isotretinoin. CONCLUSION: Micronized isotretinoin appears to have a safety profile similar to that of standard isotretinoin and to carry a lower risk of mucocutaneous events and hypertriglyceridemia.

Acne Vulgaris↗
PubMed1998

Monitoring of isotretinoin therapy by measuring the plasma levels of isotretinoin and 4-oxo-isotretinoin. A useful tool for management of severe acne.

BACKGROUND: Isotretinoin for oral therapy in severe acne conglobata and acne nodulocystica represents a significant achievement; however, the drug exerts several mucocutaneous and systemic adverse effects, besides its teratogenic potency. OBJECTIVE: The aim of this study was to investigate the plasma levels of isotretinoin and of 4-oxo-isotretinoin over long-term treatment of severe acne and to assess any correlation with the given dose, the clinical improvement and the occurrence of side effects. METHODS: Forty-one patients with severe acne and acne-related disorders were studied under long-term oral intake of isotretinoin. Therapeutic effects and side effects were evaluated prior, during and at the end of therapy. The plasma levels of isotretinoin and of its major metabolite 4-oxo-isotretinoin were measured by reversed-phase HPLC and were correlated with the administered oral dose and the number and frequency of side effects. RESULTS: Dose-dependent plasma levels of isotretinoin and its metabolite were observed. At a mean dosage of 0.75-1.0 mg/kg/day, 404 +/- 142 ng/ml were measured, whereas the plasma levels of 4-oxo-isotretinoin were 1-2x higher. The plasma levels correlated well with the orally administered dose of isotretinoin and the observed mucocutaneous side effects. CONCLUSION: The study demonstrates that measuring of the plasma levels may be a helpful tool to monitor the individual therapeutic dose regimen in patients with severe acne in order to minimize undesired side effects and to control oral intake.

Acne Vulgaris↗
PubMed2006

Facial edema induced by isotretinoin use: a case and a review of the side effects of isotretinoin.

Isotretinoin (13-cis-retinoic acid) is a retinoid that is used to treat cystic acne, comedonal acne, and other diseases. For the treatment of acne, isotretinoin is dosed at 0.5 to 2 mg/kg daily for 5 months with a target total dose of approximately 120 mg/kg. Its most common side effects are mucocutaneous and ocular in nature (ie, cheilitis, ocular sicca, and decreased dark adaptation). It can also cause xerosis. Patients should be made aware of these side effects before taking isotretinoin and also that utilization of moisturizers and eye drops can help to mitigate such side effects. Sometimes, however, the dose of isotretinoin needs to be decreased to reduce the induction of side effects. Isotretinoin's most significant side effect is the induction of birth defects if a fetus is exposed to isotretinoin, which is pregnancy category X. Isotretinoin should be used with 2 forms of birth control by fecund women. It can rarely increase serum levels of triglycerides, which can, if very elevated, be related to the development of pancreatitis and xanthomas. Isotretinoin's well-documented but rarer side effects include intracranial hypertension. It can induce bony changes. A review of the literature demonstrates that isotretinoin is not linked to depression and suicide. Facial swelling has been linked to isotretinoin use in 3 previous case reports. We note herein the first case of facial swelling that occurred in an acne patient being treated with isotretinoin who at the time the swelling developed had no cysts, comedones, pustules, or evidence of bacterial infection. Possible reasons for the patient's facial swelling include some type of retinoid induced angioedema, exacerbation of inflammation by isotretinoin, and isotretinoin induced capillary leak syndrome.

Acne Vulgaris↗
PubMedDate not supplied

Metabolism of isotretinoin. Biliary excretion of isotretinoin glucuronide in the rat.

The biliary metabolites of isotretinoin were examined after iv administration of 4-20-mg/kg doses to vitamin A-normal bile duct-cannulated rats. Analysis of bile by reverse phase high performance liquid chromatography showed that injection of isotretinoin is followed by a rapid excretion of metabolites in bile. Isotretinoin glucuronide was identified as the major metabolite in bile. A specific high performance liquid chromatography method based on the assay of generated isotretinoin in beta-glucuronidase-treated bile was developed for the determination of isotretinoin glucuronide in bile samples. The excretion rate of isotretinoin glucuronide increased rapidly to reach a maximum 55 min after dosing and then declined exponentially. After 330 min of collection, biliary excretion of isotretinoin glucuronide was almost complete, and the metabolite accounted for 34.8-37.9% of the dose. These results indicate that conjugation with glucuronic acid represents a major pathway for the metabolism of pharmacological doses of isotretinoin. The maximum excretion rate of isotretinoin glucuronide in bile increased in a linear manner with the dose of isotretinoin, and no delay was observed after the larger doses. These data suggest that glucuronidation and biliary excretion are not saturated at high pharmacological doses of isotretinoin.

Animals↗
PubMed1992

Long-term therapy with low-dose isotretinoin for prevention of basal cell carcinoma: a multicenter clinical trial. Isotretinoin-Basal Cell Carcinoma Study Group.

BACKGROUND: High-dose isotretinoin has been reported to have a prophylactic effect on nonmelanoma skin cancer, although it is associated with significant toxicity. PURPOSE: To test the effectiveness of the long-term administration of low-dose isotretinoin in reducing the occurrence of basal cell carcinoma at a new site in patients with previously treated basal cell carcinomas and to measure the toxicity associated with this regimen, we conducted a clinical trial at eight cancer centers. METHODS: Nine hundred and eighty-one patients with two or more previously confirmed basal cell carcinomas were randomly assigned to receive either 10 mg of isotretinoin or a placebo daily. Patients were followed for 36 months and monitored at 6-month intervals for skin cancer and toxic effects. RESULTS: After 36 months of treatment, no statistically significant difference in either the cumulative percent of patients with an occurrence of basal cell carcinoma at a new site or the annual rate of basal cell carcinoma formation existed between patients receiving isotretinoin and those receiving the placebo. Elevated serum triglycerides, hyperostotic axial skeletal changes, and mucocutaneous reactions were more frequent in the group receiving isotretinoin than in the control group, and these differences were all statistically significant (P less than .001). CONCLUSION: This low-dose regimen of isotretinoin not only is ineffective in reducing the occurrence of basal cell carcinoma at new sites in patients with two or more previously treated basal cell carcinomas but also is associated with significant adverse systemic effects. IMPLICATION: The toxicity associated with the long-term administration of isotretinoin, even at the low dose used in this trial, must be weighted in planning future prevention trials.

Aged↗
PubMed1996

Effects of isotretinoin on bone mineralization during routine therapy with isotretinoin for acne vulgaris.

OBJECTIVE: To examine the effects of isotretinoin on bone mineralization and other markers of calcium homeostasis in individuals receiving isotretinoin for routine therapy for severe acne vulgaris. DESIGN: Cohort study. SETTING: An academic medical center. PATIENTS: Twenty individuals receiving isotretinoin for severe acne vulgaris. INTERVENTION: None. MAIN OUTCOME MEASURE: The primary outcome was the change in bone mineralization as measured by dual-energy x-ray absorptiometry of the lumbar spine and hip before and after isotretinoin therapy. Additional measurements included serum osteocalcin, calcium, 25-dihydroxyvitamin D, 1,25-dihydroxyvitamin D, and intact parathyroid hormone and urine hydroxyproline or calcium. RESULTS: No changes were noted in bone mineralization of the lumbar spine or hip. Furthermore, no alterations were noted in serum measurements of osteocalcin, calcium, 25-dihydroxyvitamin D, intact parathyroid hormone, or urine measurements of hydroxyproline or calcium. A statistically significant change was noted in 1,25-dihydroxyvitamin D when serum from before and after isotretinoin therapy was compared. CONCLUSION: The use of isotretinoin for 20 weeks for the treatment of severe acne vulgaris does not appear to have any substantial adverse effect on bone mineralization.

Acne Vulgaris↗
PubMed1995

Comparative study of systemic interferon alfa-2a plus isotretinoin versus isotretinoin in the treatment of recurrent condyloma acuminatum in men.

OBJECTIVES: Purpose of the present study was to evaluate the effectiveness of isotretinoin versus interferon alfa-2a plus isotretinoin in the treatment of recurrent condyloma acuminatum in 86 men. METHODS: Men were randomly assigned to group A (n = 42) who received isotretinoin 1 mg/kg orally daily until remission was achieved, but not more than 3 months, or to group B (n = 44) who received interferon alfa-2a 3 x 10(5) IU subcutaneously three times weekly until remission was achieved, but not more than 8 weeks, plus isotretinoin in the same dosage as in group A. RESULTS: The reduced duration of treatment to achieve remission was statistically significant in group B (2.18 versus 2.5 months; P < 0.01) and the recurrence rate was less in group B (4 of 44 versus 16 of 42; P < 0.01). CONCLUSIONS: The results of this study are encouraging and demonstrated that the combination of isotretinoin plus interferon alfa-2a achieves higher remission rates and a shorter duration of treatment than isotretinoin alone.

Adolescent↗
PubMedDate not supplied

Differential modulation of transforming growth factor-beta by betamethasone-17- valerate and isotretinoin: corticosteroid decreases and isotretinoin increases the level of transforming growth factor-beta in suction blister fluid.

Retinoids and glucocorticoids are known to have a potential to modulate the expression of transforming growth factor-beta (TGF-beta). We investigated the effect of oral isotretinoin (13-cis-retinoic acid) on the expression of two distinct isoforms of TGF-beta, TGF-beta1 and TGF-beta2, in suction blister fluid and serum in acne patients. We also investigated the effect of topical glucocorticoid (betamethasone-17-valerate) and age on suction blister fluid TGF-beta1 in healthy volunteers. Six weeks of isotretinoin treatment caused a statistically significant 19% increase in suction blister fluid TGF-beta1. The suction blister fluid TGF-beta2 level remained below the sensitivity level of the immunoassay in many cases. Isotretinoin did not affect the serum TGF-beta1 or TGF-beta2 level. Betamethasone-17-valerate pretreatment for 3 days twice a day caused a statistically significant 17% decrease in suction blister fluid TGF-beta1. The active form of TGF-beta1 represented 5% of the total TGF-beta1 in suction blister fluid. Our diffusion calculations suggest that all TGF-beta1 and TGF-beta2 detected in suction blister fluid have diffused from systemic circulation. The increase in suction blister fluid TGF-beta1 after isotretinoin treatment seems to be of local origin, while the decrease in suction blister fluid TGF-beta1 after glucocorticoid pretreatment seems to be due to glucocorticoid-induced vasoconstriction resulting in decreased diffusion of TGF-beta1 from the circulation. Modulation of local interstitial fluid TGF-beta1 concentration may be one mechanism by which isotretinoin and glucocorticoids mediate their effects in skin.

Acne Vulgaris↗
PubMed1996

Comparative study of systemic interferon alfa-2a with oral isotretinoin and oral isotretinoin alone in the treatment of recurrent condylomata accuminata.

OBJECTIVES: We attempted to test the hypothesis that the combination of systemic interferon alfa-2a and oral isotretinoin is more effective than isotretinoin alone in the treatment of recurrent condylomata accuminata. STUDY DESIGN: Fifty seven women with recurrent condylomata accuminata were randomly assigned in two groups. Group A (n = 24) received isotretinoin alone (Roaccutan, Roche) 1 mg/kgr orally daily for 3 months or until a remission was achieved; Group B (n = 33) received Interferon alfa-2a (Roferon-A, Roche) 3 million units subcutaneously three times for 8 weeks plus isotretinoin 1 mg/Kg orally for 3 months or until a remission was achieved. RESULTS: There was no statistically significance in remission rates between the two groups (18/24 vs 28/33, p > 0.1). However the duration of treatment was statistically significantly shorter in Group B (1.9 vs 2.5 months, p < 0.01). Side effects were minimal.

Adolescent↗
PubMedDate not supplied

Clinical and laboratory adverse effects associated with long-term, low-dose isotretinoin: incidence and risk factors. The Isotretinoin-Basal Cell Carcinomas Study Group.

Adverse effects associated with the long-term low-dose regimens of retinoids used in cancer chemoprevention studies are not well described. In order to examine the clinical and laboratory adverse effects of 3 years of intervention with isotretinoin (10 mg/day) and to assess potential risk factors for developing these, we collected adverse effect data on patients participating in a randomized, placebo-controlled trial designed to evaluate the effectiveness of isotretinoin in preventing the subsequent occurrence of new basal cell carcinoma. Our results showed a significantly higher incidence of adverse mucocutaneous effects and serum triglyceride elevations in the isotretinoin group (P < 0.001). Associated risk factors included male gender, very fair skin, and elevated pretreatment triglyceride levels. The toxicity observed, although less severe and less frequent, was similar to that seen with higher doses and should be weighed with adverse skeletal effects when considering long-term treatment of patients with moderate cancer risk.

Adult↗
PubMed1987

Developmental effects of isotretinoin and 4-oxo-isotretinoin: the role of metabolism in teratogenicity.

Previous observations have indicated that isotretinoin (IT), a drug in common use for therapy of cystic acne, is teratogenic in humans but possesses low embryotoxicity in pregnant mice, probably because of its shorter half-life and limited placental transfer in rodents. In human volunteers and patients, one major blood metabolite of IT is 4-oxo-isotretinoin (4-oxo-IT) which undergoes slower elimination than IT and may itself be a participant in teratogenesis. To investigate the problem of species differences displayed by IT and the role of its metabolism, embryotoxic effects of 4-oxo-IT were examined after its single or repeated intubations into pregnant ICR mice and compared with the effects of a similar regimen of IT. The two compounds were also tested for their relative ability to suppress chrondrogenesis in the in vitro cell and organ culture assays. We found that a single dose of 4-oxo-IT, 100 mg/kg, given on day 11 of gestation (plug day = day 0 of gestation) produced a moderate incidence of limb reduction defects and cleft palate (39% and 27% of surviving fetuses, respectively), while a dose of 150 mg/kg affected virtually every fetus. IT, on the other hand, produced no defects in fetuses exposed to similar dose levels. Repeated intubations with IT, however, resulted in increasing the frequencies of limb reduction defects and cleft palate to levels obtained after 4-oxo-IT administration. We found that a 3-hour interval between IT intubations was more effective in this regard than an 8-hour interval. Repeated IT intubations also uncovered sharper stage-dependency of limb and palatal defects than obtained otherwise.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗
PubMed1999

A placebo-controlled clinical trial to compare a gel containing a combination of isotretinoin (0.05%) and erythromycin (2%) with gels containing isotretinoin (0.05%) or erythromycin (2%) alone in the topical treatment of acne vulgaris.

PURPOSE: To compare the clinical benefit of isotretinoin (0.05%) and erythromycin (2%) gels alone and in combination (Isotrexintrade mark) in acne patients. PROCEDURE: The study was a randomised placebo-controlled trial in acne patients who should benefit from topical therapy. RESULTS: All treatment groups except placebo produced a time-related reduction in lesion counts, with the combined therapy producing the largest mean decrease. Between-group comparisons showed several significant differences. CONCLUSION: Isotrexin was significantly better than placebo at all time points for inflamed and total lesions, and was better than isotretinoin at week 4. Side-effects were minimal.

Acne Vulgaris↗
PubMedDate not supplied

Changes in cytosolic calcium, bleb formation, and cell death in neural crest cells treated with isotretinoin and 4-oxo-isotretinoin.

Information regarding the cytopathologic mechanism of action of the retinoids [isotretinoin (IR) and 4-oxo-isotretinoin (4-OIR)] on neural crest cells (NCCs) in culture was sought. Those pathophysiologic alterations in cell metabolism studied were: cell blebbing (xieosis), free radical formation, cell viability, and cellular calcium homeostasis. Cells were treated with IR or 4-OIR in the presence of high (1.4 mM) and low (5.0 microM) levels of extracellular calcium ions. Recently developed techniques utilizing fluorescent molecular probes for calcium analyses, i.e., Fura 2AM, were used to study the effects of these drugs on the cytosolic calcium concentration of NCCs. The effects of IR and 4-OIR on NCC viability, [Ca++]int, were contrasted with the effects of certain sulfhydryl drugs (HgCl2, NEM, PCMBS) and calcium ionophores (ionomycin, A23187), agents known to perturb cell membranes, increase cytosolic calcium loads, and induce cell injury and subsequent cell death. Both retinoids were shown to induce an increase in the generation of superoxide radicals (SO) and increase the influx of calcium ions by the NCCs, thus increasing [Ca++]int by several hundred percent within 5 to 10 min. The liberation of SO was calcium dependent. These early effects were accompanied by an increase in cell blebbing activity. Also, a significant decrease in NCC viability was seen as early as 10 min after the addition of IR or 4-OIR to the incubation medium. 4-OIR proved to be the more potent of the two retinoids tested. The severity of these effects on NCC metabolism was dependent on medium calcium concentration with all changes being increased in the presence of the higher extracellular calcium levels. From the data presented it appears as though the retinoids cause a rapid elevation in cytosolic [Ca++]int possibly by purturbing the integrity of the cell membrane, denaturing membrane Ca-ATPase activity, or both. Retinoid-induced changes in membrane activity are evidenced by increased surface blebbing and superoxide formation. The prolonged elevation of intracellular [Ca++] may be directly related to depressed NCC viability and thus explain the known teratogenic effects of these drugs and their relationship to ectomesenchymal cell hypoplasia and craniofacial dysmorphogenesis.

Animals↗
PubMed1990

Generation of radical oxygen species by neural crest cells treated in vitro with isotretinoin and 4-oxo-isotretinoin.

The effects of isotretinoin (IR) and its primary metabolite (in the human), 4-oxo-isotretinoin (4-OIR or OIR), on isolated chick neural crest cells (NCC's) in culture were studied. NCC's were found to be deficient in both superoxide dismutase (SOD) and catalase, two of the enzymes known to function in the "scavenging" (dismutation) of toxic radical oxygen species (ROS) such as the superoxide anion and hydrogen peroxide. The addition of IR or OIR to the culture medium significantly depressed the viability of the NCC's when compared to untreated cells. OIR was more potent in this regard than IR. In the presence of either IR or OIR, NCC's generated superoxide anions (O2.), hydrogen peroxide (H2O2), and hydroxyl anions (OH.). OIR was again more potent. The cytotoxicity of IR or OIR was demonstrated by the "leakage" of radioactive chromium from prelabeled cells. The latter is suggestive of a primary surface membrane defect, most logically via the induction of lipid peroxides by the retinoids. The latter is accompanied by an increase in membrane permeability and porosity as evidenced by the fact that various fluorescently labeled molecules, including BSA-FITC (MW 69,000), gain entrance into the cytoplasm of the retinoid treated cells. No label was seen in the cytoplasm of similarly treated control cells. When SOD (200 units/ml) or catalase (400 units/ml) was added to the culture media of IR- or OIR-treated NCCs, cell viability was increased and the concentration of the various ROS generated was decreased. Membrane leakiness to chromium and FITC-BSA was also decreased in the presence of these enzymes. Free radicals, when not inactivated (dismutated), are known to be pathobiotic to most cells. Cell membranes are at a particular high risk from ROS which induce structural, physiological, and biochemical alterations in the cell membrane. The latter can have a negative effect on cell permeability, maintenance of normal ionic gradients, membrane enzyme activity, cell-to-cell communication, etc. Such defects can ultimately culminate in hypoplasia, aplasia, and cell necrosis. This study has shown that NCC's may be overtly sensitive to ROS, especially since these undifferentiated cells apparently lack inherent SOD and/or catalase activity. From this study it appears as if both IR and OIR perturb the normal functional state of NCC's by "triggering" the generation of ROS. This may certainly explain the teratogenicity of these drugs as related to the viability of neural crest derived ectomesenchymal cells and normal craniofacial morphogenesis.

Animals↗
PubMed1986

[Isotretinoin in local treatment of acne and rosacea and animal experiment studies on isotretinoin and arotinoid].

Fifteen patients with acne and 4 with rosacea were treated topically with 0.2% isotretinoin cream twice a day for 16 weeks. Inflammatory lesions responded better (30 +/- 22 versus 15 +/- 12) than non-inflammatory lesions (23 +/- 44 versus 17 +/- 24). Neither the "causal level" (123 +/- 85 versus 130 +/- 66 micrograms/cm2 nor the "replacement sum" (70 +/- 29 versus 77 +/- 30 micrograms/cm2) were changed (lipometer assay). In 150 adult male Syrian hamsters 1-2 drops of isotretinoin in concentrations varying from 0.3% to 0.001% and arotinoid ranging in concentration from 0.3% to 0.00001% in acetone were applied to the left ventral ear or the left flank organ twice a day (5/7 days) for 21 days. In higher concentrations there was a significant reduction in sebaceous gland size. Arotinoid, however, is extremely toxic. Even in concentrations as low as 0.00001% the animals showed severe side-effects within the 1st week.

Acne Vulgaris↗
PubMed2003

Isotretinoin use and subsequent depression and suicide: presenting the evidence.

The growing number of reported cases of depression and suicide associated with isotretinoin (a retinoid receptor agonist) use in patients with acne has prompted concern among dermatologists, patients, and their relatives and has triggered new warnings from regulators including depression-related, patient-informed consent forms. In establishing a cause-effect relationship, it is useful to judiciously consider whether there is an association, what is the nature of that association, if there is a plausible biological mechanism of action, the validity and reliability of measures used and the strength of study designs. Hoffmann-La Roche estimates that by April 2001 approximately 12 million patients worldwide have used isotretinoin, with 5 million patients in the US.A MEDLINE search between January 1966 and May 14 2003 of the published medical literature found 24 documented cases of isotretinoin-associated depression, with 3 suicides. One additional patient committed suicide during the fourth month of isotretinoin treatment and 3 further patients attempted suicide by taking an overdose of isotretinoin. The US FDA's Adverse Event Reporting System (AERS) contains almost 23,000 reports for isotretinoin from its approval in 1982 to December 2002. As of November 30, 2002, AERS contained 3,104 reports (US and foreign) with at least one reported psychiatric event. The FDA is aware of 173 reports of suicide (both US and foreign) in association with isotretinoin. Reports of positive dechallenge and rechallenge present a strong signal pointing to an association between isotretinoin and depression. A Hoffmann-La Roche sponsored epidemiological study failed to find any evidence of an association between isotretinoin and depression or suicide. However, the design of the study was flawed and the evidence was deemed inconclusive. Further studies using strong study designs, reliable and valid measures, and adequate sample sizes may bring us closer to the answer. The evidence suggesting a relationship between isotretinoin and depression needs to be weighed against the increasing prevalence of depression among adolescents and young adults and the psychological impact of acne. The literature contains credible evidence that isotretinoin treatment may reduce the psychosocial impact of acne in some patients. At the present time, there is no known pharmacological mechanism that would account for psychiatric symptomatology as a result of isotretinoin treatment; however, retinoid receptors are widely distributed in the brain and more research is needed to ascertain whether they have a role in depression. In the meantime, for the practitioner, the obvious benefit of isotretinoin in treating acne should encourage continued use. However, patients and their relatives must be informed and depressive symptoms should be actively assessed at each visit and, if necessary, referral to a psychiatrist, antidepressant therapy or discontinuation of isotretinoin should be considered.

Acne Vulgaris↗
PubMed1997

Negligible systemic absorption of topical isotretinoin cream: implications for teratogenicity.

The objective of the study was to assess the extent of systemic exposure of retinoic acid metabolites after excessive application of 0.1% isotretinoin cream in patients with photodamaged skin. This was a single-center, open-label, noncomparative, multiple-dose study of isotretinoin cream. Eighteen female patients with photodamaged skin received a 10 g topical application of isotretinoin cream once daily to a surface area of approximately 2,300 cm2 for 42 days. The patients were not allowed to have high vitamin A-containing foods, vitamin A supplements, or concomitant medications during the entire study period. Plasma levels of four retinoic acids (isotretinoin, tretinoin, 4-oxo-isotretinoin, and 4-oxo-tretinoin) were evaluated after 42 days of isotretinoin application and compared with baseline (pretreatment) levels. The mean area under the curve (AUC) in plasma increased by 48% (+/-SE 9.2) and 77% (+/-13) from the 24-hour pretreatment baseline level for isotretinoin and 4-oxo-isotretinoin, respectively, after treatment with excessive amounts of isotretinoin cream, suggesting systemic absorption of isotretinoin cream. This increase in systemic exposure of retinoic acids was less than that reported earlier after the U.S. recommended daily allowance of 5,000 i.u. of vitamin A supplementation (isotretinoin 141 +/- 19% and 4-oxo-isotretinoin 171 +/- 27%). The minimal systemic availability of isotretinoin cream compared with the U.S. recommended daily allowance for vitamin A supplements provides reasonable evidence for lack of its potential teratogenic risk.

Administration, Cutaneous↗