The phenomenon of phototoxicity and long-term risks of commonly prescribed and structurally diverse drugs

Photosensitivity to structurally diverse drugs is a common but under-reported adverse cutaneous reaction and can be classified as phototoxic or photoallergic. Phototoxic reactions occur when the skin is exposed to sunlight after administering topical or systemic medications that exhibit photosensitizing activity. These reactions depend on the dose of medication, degree of exposure to ultraviolet light, type of ultraviolet light, and sufficient skin distribution volume. Accurate prediction of the incidence and phototoxic response severity is challenging due to a paucity of literature, suggesting that phototoxicity may be more frequent than reported. This paper reports an extensive literature review on phototoxic drugs; the review employed pre-determined search criteria that included meta-analyses, systematic reviews, literature reviews, and case reports freely available in full text. Additional reports were identified from reference sections that contributed to the understanding of phototoxicity. The following drugs and/or drug classes are discussed: amiodarone, voriconazole, chlorpromazine, doxycycline, fluoroquinolones, hydrochlorothiazide, nonsteroidal anti-inflammatory drugs, and vemurafenib. In reviewing phototoxic skin reactions, this review highlights drug molecular structures, their reactive pathways, and, as there is a growing association between photosensitizing drugs and the increasing incidence of skin cancer, the consequential long-term implications of photocarcinogenesis.

Propylene Glycol Improves Stability of the Anti-Inflammatory Compounds in Scutellaria baicalensis Extract

Scutellaria baicalensis root extracts have been useful for external skin care and have been commercialized for years. Here, a comprehensive study was conducted to investigate the difference between 20% propylene glycol (PG) and water used as the storage solvent for a time course analysis of their remaining biological activities and ingredient compositions versus their freshly prepared conditions. Of the four major components in the 20% PG solvent, more than 80% of the components were retained after storage for two months, but in water only baicalin and wogonin were retained. The relative antibacterial activities, antioxidant properties and anti-inflammatory activities of the 20% PG solvent group were better than those of the water solvent group. Taken together, we demonstrated that these activities improved when PG, a common solvent used in many product formulas, was used as the storage solvent for the S. baicalensis extract.

Is it safe to use visible blue light-emitting diode phototherapy for neonatal jaundice in infants who are also treated with amiodarone?

Amiodarone is a useful treatment for neonatal cardiac arrhythmias. A minority of neonates with arrhythmias treated with amiodarone may also develop neonatal jaundice. Phototherapy is recommended to treat neonatal jaundice. However, amiodarone is known to cause skin reactions when patients are exposed to light. Therefore phototherapy may not be administered due to concerns about this interaction. Exchange transfusions are used as an alternative to phototherapy to avoid the interaction. However, exchange transfusions are associated with serious complications such as the transmission of bloodborne disease, seizures and haemodynamic instability. We report a literature review and outcome of a premature infant treated with amiodarone and visible blue light-emitting diode (LED) phototherapy. Phototherapy was used for 54 hours and no skin reactions were observed. This is because visible blue LED phototherapy lamps emit predominantly visible light. Therefore exposure to ultraviolet light that is known to cause amiodarone phototoxicity is minimised.

Amiodarone: A potential risk factor for retinal phototoxicity

Purpose

To report the only known case, to our knowledge, of amiodarone induced retinal phototoxicity following vitrectomy surgery.

Observations

A 66-year-old male presented with visual acuity of 20/150 OS secondary to an epiretinal membrane (ERM). Patient was on oral amiodarone for atrial fibrillation. Baseline spectral domain optical coherence tomography (SD-OCT) revealed an ERM with retinal thickening and schisis. The patient underwent an uncomplicated pars plana vitrectomy and membrane peel using standard vitrectomy settings and illumination. Triamcinolone was used to stain the ERM intraoperatively. ICG was not used. On post-operative day one, vision was count finger (CF) at 1′. At post-operative week one, vision was unchanged and SD-OCT showed macular edema. At post-operative month one, vision remained CF at 1′ and macular edema resolved with residual pigmentary changes and subretinal fibrosis resembling phototoxic damage. SD-OCT at one month showed resolution of macular edema, retinal pigment epithelium hyperplasia and an indistinct ellipsoid layer. Fluorescein angiography did not show any neovascularization. At three month follow-up, patient's vision, exam and OCT findings remained unchanged.

Conclusions and importance

Many pharmacologic agents have the ability to alter a patient's sensitivity to solar or artificial radiation. Drugs act as photosensitizers that lead to photochemical damage. Amiodarone has been reported to have such photosensitizing properties in humans. This report describes a case of retinal phototoxicity from intraoperative light exposure photosensitized by systemic amiodarone use.

Cutaneous adverse reactions of amiodarone

Dermatological complications of amiodarone are commonly encountered problems in therapy. The incidence in the population of patients with prolonged use of amiodarone reaches nearly 75% according to various sources. Nevertheless, they are often misdiagnosed or overlooked. The aim of this review is to present the current state of knowledge about skin changes induced by amiodarone, including phototoxic and photoallergic reactions, as well as hyperpigmentation. In most cases, the adverse effects are reversible and disappear after discontinuation of the drug. Although the dermatological complications usually do not influence the outcome of the therapy and rarely cause discontinuation of treatment, they have a great impact on patient quality of life.

Amiodarone supplants lidocaine in ACLS and CPR protocols

Amiodarone is an antiarrhythmic medication used to treat and prevent certain types of serious, life-threatening ventricular arrhythmias. Amiodarone gained slow acceptance outside the specialized field of cardiac antiarrhythmic surgery because the side-effects are significant. Recent adoption of amiodarone in the ACLS (Advanced Cardiac Life Support) protocol has somewhat popularized this class of antiarrhythmics. Its use is slowly expanding in the acute medicine setting of anesthetics. This article summarizes the use of Amiodarone by anesthesiologists in the operating room and during cardiopulmonary resuscitation.