The weeks and the cumulative doses of the first adverse events related to oral isotretinoin in acne patients: analysis of 300 patients

Comparing the frequency of isotretinoin-induced hair loss at <0.5-mg/kg/d versus ≥0.5-mg/kg/d dosing in acne patients: A systematic review

Over 1 million isotretinoin prescriptions are authorized in the United States per year. An insight into the frequency, dose dependency, timing, and reversibility of hair loss associated with isotretinoin treatment for acne vulgaris could help guide dosing regimens and patient counseling. The objective of this systematic review was to assess the frequency of hair loss in patients with acne vulgaris on <0.5 mg/kg/d daily doses of isotretinoin versus the frequency of hair loss in patients with acne vulgaris on ≥0.5 mg/kg/d daily doses of isotretinoin.

An Embase and MEDLINE search was conducted on July 15, 2020, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The review focused on acne vulgaris patients. The treatment of acne vulgaris is the most common use of isotretinoin, and the population is typically younger and with fewer comorbidities.

Twenty-two studies reported hair loss with oral isotretinoin treatment. A frequency analysis suggested that patients with acne vulgaris on <0.5 mg/kg/d of isotretinoin experienced hair loss at a frequency of 3.2% (n = 18/565) compared with those on ≥0.5 mg/kg/d, who experienced hair loss at a frequency of 5.7% (n = 192/3375). Inferential statistics were not possible.

Physicians should consider counseling patients about the risk of telogen effluvium prior to drug initiation, as is commonly done for other side effects. The potential trend of increased hair loss frequency at a higher daily dosing warrants further investigation using higher-quality research.

Effect of Serum 25 Hydroxy Vitamin D Level on Isotretinoin-Induced Musculoskeletal Symptoms: A Cross-Sectional Study

Isotretinoin (ISO) is a drug which is used for the treatment of severe and refractory acne vulgaris (AV), over the last few decades. The drug has various musculoskeletal side effects. The aim of this study was to investigate relationship between serum 25 hydroxy (OH) vitamin D levels and the ISO-induced musculoskeletal side effects in patients with AV. We included 87 patients receiving ISO and had musculoskeletal symptoms as adverse effect (AE) group. Another 90 patients receiving ISO for AV and had any musculoskeletal complaints were recruited as control (C) group. Locomotor system examination of the patients was performed by the same clinician. Serum 25 OH vitamin D levels of the all participants were measured. Patients in the AE group were divided into three subgroups by serum 25 OH vitamin D levels. Patients with serum 25 OH vitamin D level lower than 10 ng/ml was classified as Group I, the ones between 10-20 ng/ml as Group II and those higher than 20 ng/ml were classified as Group III. AE and C groups were similar in terms of age and sex (p > 0.05). There was no statistically significant difference in the mean serum vitamin D levels between two groups (p = 0.17). Also, there was no significant difference in number of arthralgia (p = 0.30), myalgia (p = 0.29), low back pain (p = 0.10) and sacroiliitis (p = 0.17) between three subgroups in AE group. In addition, we found no statistically significant correlation between the serum vitamin D levels and age, cumulative dose of ISO, arthralgia, myalgia and sacroiliitis parameters in AE group (p > 0.05). Serum 25 OH vitamin D levels between the AE and C groups were similar. We also found that no significant difference in musculoskeletal adverse events between AE subgroups. Therefore, it can be concluded that vitamin D deficiency has no effect on the musculoskeletal adverse events in patients receiving ISO.

Pityriasis rosea-like eruption induced by isotretinoin

Pityriasis rosea is a common, self-limited and inflammatory skin disease. The etiology is not clearly known. Viral agents, autoimmunity, psychogenic factors and drugs have all been suggested as risk factors. Isotretinoin is usually used in the treatment of resistant, nodulocytic acne. We present a case of pityriasis rosea-like eruption induced by isotretinoin. To our knowledge, this is the second clinical case of pityriasis rosea-like eruption induced by isotretinoin.

Trypanocidal Effect of Isotretinoin through the Inhibition of Polyamine and Amino Acid Transporters in Trypanosoma cruzi

Polyamines are essential compounds to all living organisms and in the specific case of Trypanosoma cruzi, the causative agent of Chagas disease, they are exclusively obtained through transport processes since this parasite is auxotrophic for polyamines. Previous works reported that retinol acetate inhibits Leishmania growth and decreases its intracellular polyamine concentration. The present work describes a combined strategy of drug repositioning by virtual screening followed by in vitro assays to find drugs able to inhibit TcPAT12, the only polyamine transporter described in T. cruzi. After a screening of 3000 FDA-approved drugs, 7 retinoids with medical use were retrieved and used for molecular docking assays with TcPAT12. From the docked molecules, isotretinoin, a well-known drug used for acne treatment, showed the best interaction score with TcPAT12 and was selected for further in vitro studies. Isotretinoin inhibited the polyamine transport, as well as other amino acid transporters from the same protein family (TcAAAP), with calculated IC₅₀ values in the range of 4.6–10.3 μM. It also showed a strong inhibition of trypomastigote burst from infected cells, with calculated IC₅₀ of 130 nM (SI = 920) being significantly less effective on the epimastigote stage (IC₅₀ = 30.6 μM). The effect of isotretinoin on the parasites plasma membrane permeability and on mammalian cell viability was tested, and no change was observed. Autophagosomes and apoptotic bodies were detected as part of the mechanisms of isotretinoin-induced death indicating that the inhibition of transporters by isotretinoin causes nutrient starvation that triggers autophagic and apoptotic processes. In conclusion, isotretinoin is a promising trypanocidal drug since it is a multi-target inhibitor of essential metabolites transporters, in addition to being an FDA-approved drug largely used in humans, which could reduce significantly the requirements for its possible application in the treatment of Chagas disease.

Polyamines are polycationic compounds essential for the regulation of cell growth and differentiation. In contrast with other protozoa, Trypanosoma cruzi, the etiological agent of Chagas disease, is auxotrophic for polyamines; therefore the intracellular availability of these molecules depends exclusively on transport processes. It was previously demonstrated that the lack of polyamines in T. cruzi leads to its death, making the polyamine transporter an excellent therapeutic target for Chagas disease. In this work, the polyamine permease TcPAT12 was selected as a target for drug screening using 3000 FDA-approved compounds and computational simulation techniques. Using two combined virtual screening methods, isotretinoin, a well-known and safe drug used for acne treatment, bound to substrate recognition residues of TcPAT12 and was chosen for further in vitro studies. Isotretinoin inhibited not only the polyamine transport but also all tested amino acid transporters from the same protein family as TcPAT12. Interestingly, isotretinoin showed a high trypanocidal effect on trypomastigotes, with an IC₅₀ in the nanomolar range. Autophagy and apoptosis were proposed as mechanisms of parasites death induced by isotretinoin. These results suggest that isotretinoin is a promising trypanocidal drug, being a multi-target inhibitor of essential metabolites transporters.