Hydroxychloroquine in dermatology: New perspectives on an old drug

Abstract

Hydroxychloroquine is an age-old drug whose use as an immunomodulatory agent with a low side-effect profile continues to expand. We present a review of this drug including recently updated prescribing recommendations and a summary of its clinical application in dermatology. A maximum daily dose of 5.0 mg/kg based on actual body weight and no greater than 400 mg is advised in order to reduce the risk of retinopathy, which is potentially permanent and has an estimated prevalence of 7.5% at 5 years on standard dosing. Baseline ophthalmologic assessment followed by annual screening after 5 years is recommended; however, closer monitoring should be considered in the setting of existing retinopathy, a cumulative dose > 1000 g or renal dysfunction. Hydroxychloroquine is now considered to be safe in pregnancy, and routine glucose-6-phosphate dehydrogenase (G6PD) deficiency testing is not required. Smoking can significantly decrease its efficacy although the reason is still uncertain. Hydroxychloroquine appears to also demonstrate antineoplastic and cardioprotective benefits.

In-line treatments and clinical initiatives to fight against COVID-19 outbreak

“… Overdose cause chloroquine poisoning which may lead to cardiac arrest Found effective in COVID-19 associated pneumonia and other symptoms Currently under clinical trial [ [59] , [60] , [61] ] Hydroxychloroquine Antimalarial Malaria and autoimmune disorder like rheumatoid arthritis, lupus erythematosus Firstly, synthesized in 1946 and approved in 1955 by USFDA Oral tablets Nausea, vomiting, diarrhea, headache, reduced appetite, retinopathy, heart problems, etc. Overdose may lead to heart failure Effective in preliminary investigations against COVID-19 Under clinical trial [ 62 , 63 ] Remdesivir Antiviral (nucleotide analog) Ebola, Marburg & other viral infections Developed by Gilead Sciences Designated as an orphan drug in Europe by Gilead Intravenous injection Nausea, Vomiting Improvement of in vitro and in vivo SARS-CoV-2 model Under phase III clinical trial by Gilead Sciences [ 64 , 65 ] Favipiravir Antiviral (RNA Polymerase inhibitor) Influenza, also effective against Ebola infection Developed by Toyama Chemicals, Japan, approved for clinical application in 2014 in Japan Oral Tablet Nausea, Vomiting, Sore throat Effective in preliminary investigations against COVID-19 Under clinical trial [ 66 ]; Mak, 10-03-2020; Xinhua, 17-03-2020) Penciclovir Antiviral (DNA polymerase inhibitor)/guanosine analog Herpes virus disease Launched in 2017 by Fujifilm Toyama Chemical Topical (cream) Headache, nausea, dyspepsia, increased serum lipase, abdominal pain, hyperbilirubinemia & dizziness No satisfactory response in in vitro ...…”

Enantiomers of Chloroquine and Hydroxychloroquine Exhibit Different Activities Against SARS-CoV-2 in vitro, Evidencing S-Hydroxychloroquine as a Potentially Superior Drug for COVID-19

“…Long term and higher doses other than the recommended maximal dose for chloroquine and hydroxychloroquine (300 mg/kg and 400 mg/kg, respectively, according to the FDA) put the patients at risk of adverse effects such as irreversible retinopathy, neuropathic, and cardiac toxicities. 38,[40][41]57 One of the major adverse effects associated with the clinical applications of CQ and HCQ is ocular toxicity manifested as pigmentary retinopathy, especially at higher doses, while the mechanism remains unelucidated.…”

“…38 Originally developed as a safer alternative to CQ for treating malaria, the analogous compound hydroxychloroquine sulfate 39 has become a popular drug for treating autoimmune diseases including rheumatoid arthritis (RA) and system lupus emphysema (SLE). [40][41] In fact, it is the 2 nd most prescribed medicine for rheumatoid arthritis in the United States, with nearly half a billion tablets dispensed in 2019. Both drugs have a long history as inexpensive and well-received treatment options for malaria, autoimmune, as well as infectious diseases, even for women patients during pregnancy.…”

Hydroxychloroquine: From Pharmacological Profile to Neglected Adverse Reactions

“…Although case reports related to HCQ-induced hepatotoxicity are very rare, care should be taken in the case of pre-existing liver disease. No specific hepatic dose adjustment guidelines are available, but it has been generally recommended to use a more conservative dose in the presence of liver disease (11,27). It should be remembered that there is a risk of acute hepatitis, even at recommended dosages of antimalarial drugs, in patients with pre-existing porphyria cutanea tarda (12,13).…”