Amiodarone keratopathy. Correlation to dosage and duration

Amiodarone-induced ocular and extra-ocular toxicity: a retrospective cohort study

Amiodarone (AMD) is a largely employed anti-arrhythmic agent for the treatment of recurrent supraventricular and ventricular tachyarrhythmias. Because of its lipophilic properties, prolonged half-life and prevailing biliary excretion, it is not rarely responsible for potentially severe adverse events that can involve one or more organs with a prevalence ranging from 15% in the first year of drug intake to 50% in patients treated for a longer time. In addition to pro-arrhythmia effects, AMD toxicity may result in a variable combination of clinical manifestations, including visual impairment, thyroid dysfunctions, pulmonary diseases, liver injury, neutropenia or thrombocytopenia. We aimed to describe the AMD-induced ophthalmologic and non-ophthalmologic side effects observed in a longitudinal cohort of patients. Seventeen Caucasian patients, who were on amiodarone therapy for a variable period, were enrolled in this retrospective, cross-sectional, observational study. All of them were referred to the Department of Ophthalmology and Neuroscience of the University of Bari, Italy, because of visual disturbances of variable severity. Three patients were given 3 intravenous boluses of 150 mg AMD followed by progressively decreasing oral doses, whereas 14 patients received a loading daily dose of 600-1200 mg orally, reduced after 2-3 weeks to a maintenance daily dose of 200-400 mg. All patients underwent complete clinical and laboratory assessments, according to a standard protocol. Ophthalmologic examination included intraocular pressure, ocular motility, visual field testing, angiography, optical coherence tomography, best-corrected visual acuity (BCVA) and grading of AMD-induced keratopathy by slit-lamp biomicroscopy. At diagnosis, eye disorders ranging from blurred vision and deterioration of visual acuity to eye redness and progressive glare were reported in 14 patients and lasting photophobia in the remaining 3 patients. Verticillate keratopathy (VK), stage 1-4, was diagnosed in all of them. Following AMD cessation, the patients were checked after a mean of 94 days and clear corneas were found in 12 of them, whereas lower-stage VK persisted in 5 patients. A 20/40 visual outcome or better was detected in 29 of 34 eyes (85.3%). Bilateral optic disk edema was found in 3 patients. Fundoscopic examination performed 23 months after AMD discontinuation showed that optic disk edema was reduced in all 3 patients, though to a variable extent. Optic neuropathy with protracted disk edema was diagnosed in a single patient who complained of progressive visual loss. Almost 2 months after AMD cessation, disk edema was reduced in OD > OS and BCVA partially improved. Extra-ocular manifestations included poorly symptomatic hypothyroidism in 2 patients, and overt myxedema, cholestatic liver injury, pancytopenia and interstitial pneumonitis associated with subclinical hypothyroidism in one patient each. A point stemming from our study and not clearly emphasized in the literature is that while a higher maintenance dose of AMD for a longer time was responsible for the most advanced grade 4 VK, no correlation was found between the occurrence of extra-ocular manifestations and the severity of ophthalmological signs or complaints. Patients assuming AMD should undergo close monitoring by specialist clinicians of a multidisciplinary team with the aim of an early recognition of eye, thyroid, liver and lung toxicities, thus preventing more serious complications.

Impact of Nontreatment Duration and Keratopathy on Major Adverse Cardiovascular Events in Fabry Disease: A Nationwide Cohort Study

Fabry disease (FD) is a rare inherited X-linked lysosomal storage disorder that results in the progressive accumulation of glycosphingolipids in multiple organs. Early FD-specific treatments may improve clinical outcomes; however, clinical evidence about early FD treatment is limited. We aimed to determine the cardiovascular outcomes of patients with FD who received enzyme replacement therapy. This nationwide observational study was conducted using the National Health Claims database of the Korean population with FD. The primary outcome was major adverse cardiovascular events (MACEs). MACE risk factors in FD were evaluated using time-dependent Cox regression. Between January 2007 and April 2022, 188 patients with FD were analyzed. Among them, 22 (11.7%) experienced MACE (males: 14/95 [14.7%]; females: 8/93 [8.6%]). The mean age at MACE diagnosis was 53.5 ± 11.0 years in all patients with FD, which was lower in males compared with in females (49.7 ± 9.6 vs. 60.0 ± 10.7 years, p = 0.030). Multivariate analysis (HR, 95% CI) revealed that age (1.042; 1.004-1.082) and duration of FD nontreatment (1.040; 1.003-1.078) were significant MACE risk factors in all patients. In males, age (1.080; 1.032-1.131), FD nontreatment duration (1.099; 1.048-1.152), and keratopathy (18.920; 4.174-85.749) were significant MACE risk factors in multivariate analysis. In females, the only significant MACE risk factor was a high Charlson comorbidity index score (1.795; 1.229-2.622). In conclusion, duration of FD nontreatment and keratopathy are significant MACE risk factors in males with FD. These findings suggest the importance of early initiation of FD-specific treatment and careful evaluation of keratopathy in males with FD.

Ophthalmic Manifestations in Fabry Disease: Updated Review

Fabry disease (FD) is an X-linked lysosomal storage disorder, causing Gb-3 (globotriaosylceramide) buildup in cellular lysosomes throughout the body, in particular in blood vessel walls, neuronal cells, and smooth muscle. The gradual accumulation of this glycosphingolipid in numerous eye tissues causes conjunctival vascular abnormalities, corneal epithelial opacities (cornea verticillata), lens opacities, and retinal vascular abnormalities. Although a severe vision impairment is rare, these abnormalities are diagnostic indicators and prognostics for severity. Cornea verticillata is the most common ophthalmic feature in both hemizygous men and heterozygous females. Vessel tortuosity has been linked to a faster disease progression and may be useful in predicting systemic involvement. New technologies such as optical coherence tomography angiography (OCTA) are useful for monitoring retinal microvasculature alterations in FD patients. Along with OCTA, corneal topographic analysis, confocal microscopy, and electro-functional examinations, contributed to the recognition of ocular abnormalities and have been correlated with systemic involvement. We offer an update regarding FD ocular manifestations, focusing on findings derived from the most recent imaging modalities, to optimize the management of this pathology.

Thyroid and Eye: Where They Meet in Clinical Practice

OBJECTIVE

Thyroid Hormones (TH) are essential for normal growth, development and continued optimal function of most of the body organs including the eye. TH signaling plays a central role in the regulation of retinal development and maturation. Deficiency in TH during fetal and early postnatal development impairs growth of the eye and proliferation of all retinal cell types. The present article reviews the most important topics of the different derangements in thyroid function and structure and its relation with eye diseases.

METHODS

A literature search strategy was conducted for all English-language literature.

RESULTS

From a clinical practice viewpoint, it should be mentioned that both hypothyroidism and hyperthyroidism are accompanied by ocular diseases i.e. thyroid-associated ophthalmopathy, diabetic retinopathy and age-related macular degeneration. Although the orbit and globe are not common sites for metastatic thyroid cancers, orbital metastasis may be the primary clinical manifestation of thyroid carcinoma. Finally, some medications as amiodarone may be accompanied by both thyroid dysfunction and adverse ocular events.

CONCLUSION

Thyroid disorders and eye diseases are interrelated through several mechanisms thus, awareness of this relation has a great impact on early diagnosis and treatment.

Amantadine can induce intra-epithelial deposition in the cornea

Purpose

Amantadine has been reported to cause various corneal complications, such as superficial punctate keratitis, corneal endothelial dysfunction, and corneal edema. However, there have been no reports of amantadine-induced deposits in the corneal epithelium. Here, we describe the first case with amantadine-induced deposits in the corneal epithelium proved by confocal biomicroscopy.

Observations

An 81-year-old woman presented with impaired vision in both eyes. She had been treated with amantadine for 9 years. Corrected visual acuity was 0.8 in both eyes. Furthermore, both eyes showed opacities in the corneal epithelial corneal layer. On confocal biomicroscopy, there were highly reflective deposits in corneal epithelial cells. There were no pathological findings in the stroma and endothelium. Two months after discontinuation of amantadine, corneal opacities disappeared, and visual acuity was 1.0 in both eyes.

Conclusions

Administration of amantadine can cause deposits in corneal epithelial cells.

In Vivo Confocal Microscopic Observations of Vortex Keratopathy in Patients with Amiodarone-Induced Keratopathy and Fabry Disease

Purpose

To compare the morphology of two types of vortex keratopathy: amiodarone-induced keratopathy and the Fabry disease-associated keratopathy.

Patients and Methods

Eight patients who were receiving oral amiodarone therapy and 3 patients with Fabry disease, a mother and her 2 daughters, were examined by slit-lamp biomicroscopy and in vivo confocal microscopy (IVCM) regularly.

Results

Amiodarone-induced keratopathy developed in 7 of the 8 patients, and it was detected as early as 7 days by IVCM and 14 days by slit-lamp biomicroscopy. The in vivo confocal microscopic images showed a clustering of corneal epithelial cells with a highly reflective cytoplasm in both types of keratopathy. In the amiodarone-induced keratopathy, the highly reflective epithelial cells were first found at the center of the cornea and then spread to the periphery with increasing time on amiodarone. In Fabry disease, the highly reflective epithelial cells were consistently observed extending from the limbus to the central cornea.

Conclusion

These findings suggest that the corneal epithelial cells most likely endocytose amiodarone from the tear film in the amiodarone-induced keratopathy. In Fabry disease, globotriaosylceramide deposits are taken up by the lysosomes of the limbal epithelial stem cells, and they differentiate and migrate to the center of the cornea to form the whorl pattern.

Confocal Microscopy Observation of Cornea Verticillata After Vandetanib Therapy for Medullary Thyroid Carcinoma

PURPOSE

To report 2 cases of cornea verticillata (CV) after vandetanib treatment for medullary thyroid carcinoma (MTC).

METHODS

In this retrospective interventional, case-report study, 2 patients who under vandetanib treatment for MTC were referred to our ophthalmology department because of vision complaints. Both subjects underwent a complete ophthalmologic examination, including confocal microscopy (CM) using the Heidelberg Retina Tomograph and Rostock Cornea Module.

RESULTS

A 70-year-old man and a 43-year-old woman, both with a history of MTC under treatment with vandetanib for 5 months and 30 months, respectively, presented with blurred vision. In both patients, a mild CV pattern was observed although deposits were more evident in the male patient. CM images showed hyperreflective deposits in the corneal epithelium and subepithelial nerve plexus. Bright microdots were also seen throughout the stroma, along with a few hyperreflective keratocytes in the anterior stroma.

CONCLUSIONS

In both patients, vandetanib seemed to be the cause of CV. The CM images supported the idea of drug-lipid complex deposits in vandetanib-induced CV.

Recovery From Amiodarone-Induced Cornea Verticillata by Application of Topical Heparin

PURPOSE

To report a case of amiodarone-induced vortex keratopathy-associated anatomical findings and subjective visual perception before and after treatment with topical heparin eye drops.

METHODS

Case report.

RESULTS

A 76-year-old man complained of halos in his vision in both his eyes due to prominent bilateral cornea verticillata. For treatment of cornea verticillata, we prescribed unpreserved eye drops of a sterile, phosphate-free solution of 0.1% sodium hyaluronate with 1300 IU/mL heparin sodium 3 times daily to the left eye, whereas the other side served as the control. The area of corneal deposits was measured by 2 examiners before and at the 1- and 3-month examination. At last follow-up, cornea verticillata had been reduced from 6 to 2 mm in area by approximately 66% from grade-III to grade-II amiodarone keratopathy.

CONCLUSIONS

In patients using amiodarone, clearing of cornea verticillata may be achieved by topical use of unpreserved eye drops of a sterile, phosphate-free solution of 0.1% sodium hyaluronate with 1300 IU/mL heparin sodium.

Corneal Densitometry as a Novel Technique for Monitoring Amiodarone Therapy

PURPOSE

The clinical efficacy and toxicity of amiodarone may be determined more effectively by tissue deposition than by levels of the agent in serum. Therefore, corneal densitometry might be useful for therapeutic monitoring. The aim of the study is to evaluate Scheimpflug corneal densitometry in patients with amiodarone keratopathy (AK).

DESIGN

Comparative case series.

PARTICIPANTS

Sixty-six patients receiving amiodarone therapy and 66 healthy controls were consecutively enrolled in this study.

METHODS

Patients were examined using the Oculus Pentacam (Wetzlar, Germany).

MAIN OUTCOME MEASURES

Densitometry data from different corneal layers and different annuli were extracted, analyzed, and compared with densitometry values of healthy controls. Duration of treatment, cumulative dose, Orlando stage (slit-lamp biomicroscopy), and serum concentrations of amiodarone and N-desethylamiodarone also were determined, and the correlation to different densitometry data was evaluated.

RESULTS

The total corneal light backscatter at total corneal thickness and at total diameter was significantly higher in the amiodarone group compared with the control group (AK group: 28.3±5.2; control group: 24.4±4.2; P < 0.001). Upon dividing the corneal surface into different layers at total thickness, the differences were significant in all layers (P < 0.001). The serum concentrations of the metabolite N-desethylamiodarone correlate with densitometry values, especially in the 0- to 2-mm annulus in the anterior layer (r = 0.419; P = 0.001), whereas the cumulative dose and duration of treatment correlate significantly with the densitometry values in the 0- to 2-mm annulus at total thickness (P = 0.014 and P = 0.022, respectively).

CONCLUSIONS

Corneal densitometry is a useful, objective method for quantifying AK and can help in monitoring amiodarone therapy. The serum concentration of the active metabolite N-desethylamiodarone correlates with the extent of keratopathy in the anterior layer, whereas chronic changes in the stroma correlate with the cumulative dose and duration of treatment.

Examining the safety of amiodarone

INTRODUCTION

Amiodarone is the most widely used antiarrhythmic agent, with demonstrated effectiveness against all the spectrum of cardiac tachyarrhythmias. The risk of adverse effects acts as a limiting factor to its utilization especially in the long term. This article systematically reviews the published evidence on amiodarone versus placebo to examine its safety as an antiarrhythmic drug.

AREAS COVERED

Authors collected data on adverse effects reported in 49 randomized placebo-controlled trials with amiodarone. Adverse effects were classified according to the organ/system involved. Pooled estimates of the number needed to treat (NNT) and to harm (NNH) versus placebo were calculated.

EXPERT OPINION

Amiodarone is effective for both the acute conversion of atrial fibrillation (AF) (11 trials, NNT = 4 at 24 h; p = 0.003) and the prevention of postoperative AF (18 trials, NNT = 8; p < 0.001), although with an increased risk of bradycardia, hypotension, nausea or phlebitis (pooled NNH = 4; p < 0.001). Amiodarone administration for the maintenance of sinus rhythm has a favorable net clinical benefit (pooled NNT = 3; p < 0.001 versus pooled NNH for either thyroid toxicity, gastrointestinal discomfort, skin toxicity or eye toxicity = 11; p < 0.001). Treatment with amiodarone for the prophylaxis of sudden cardiac death has less favorable net clinical benefit (15 trials, NNT = 38; p < 0.001 versus NNH for either thyroid toxicity, hepatic toxicity, pulmonary toxicity or bradycardia = 14; p < 0.001). Amiodarone treatment in this setting should be used in only selected cases.

Amiodarone-induced keratopathy: full-thickness corneal involvement

PURPOSE

To report a case of amiodarone-induced keratopathy involving the entire cornea, including the endothelium.

METHODS

Clinical case description and documentation with confocal laser scanning microscopy using the Heidelberg Retinal Tomography II (HRT II).

RESULTS

A 65 year-old man with a history of blurred vision and seeing halos around lights had been treated with amiodarone for 6 years. Best-corrected visual acuity was 20/25 in each eye. Slitlamp examination of both eyes showed a bilateral, symmetric, whorllike pattern of brown deposits in the inferocentral corneal epithelium. Diffuse and fine deposits resembling keratic precipitates in the central part of the endothelial face were also detected. Examination of the lens, optic nerve, and fundus in each eye did not show any abnormalities that could be attributed to the amiodarone therapy. Severe endothelial deposition was documented with the confocal laser scanning microscope of the HRT II.

CONCLUSIONS

Amiodarone-induced keratopathy with confluent and diffuse endothelial deposition is rare, and it may be indicative of a more severe toxicity associated with amiodarone.

Amiodarone keratopathy and rigid contact lens wear

Two cases are presented of patients wearing rigid gas permeable contact lenses who exhibited the typical fan-shaped patterns of corneal pigment deposition related to long-term medication containing amiodarone. The vortex corneal epitheliopathy and contact lens tolerance were monitored over several years. In both cases, the lens material was replaced with one incorporating an ultra-violet light inhibitor in view of the possibility of medically induced photosensitivity.

Amiodarone Keratopathy

PURPOSE

To evaluate the characteristics and evolution of corneal morphologic changes induced by systemic amiodarone treatment by using in vivo slit scanning confocal microscopy in an attempt to understand the pathogenesis of corneal and other systemic side effects of this drug.

METHODS

Forty-nine eyes of 25 consecutive subjects receiving amiodarone therapy (group A) and 26 eyes of 13 age- and sex-matched healthy control subjects (group B) were enrolled in the study.

RESULTS

In group A, the mean dosage of amiodarone was 224.0 +/- 71.3 mg, and the mean duration of treatment was 21.3 +/- 20.9 months. In eight (8 of 49,16.3) eyes of four patients, no deposition was observed, neither by slitlamp nor by confocal microscopy. The deposition could be detected as early as 2 months after the onset of treatment in 41 (41 of 49, 83.7%) eyes, by slitlamp and confocal microscopy. Deposition was significantly correlated with the duration of treatment and, therefore, the cumulative dose of the drug ingested. Deposits were observed as bright, hyper-reflective spots that were localized intracellularly and were present at the level of basal lamina of all 41 (100%) corneas in which deposition could be observed at confocal microscopy. Deposits were also observed in the superficial epithelium, anterior stroma, mid stroma, and subepithelial nerves in eyes with grade 2 to 4 keratopathy. Additionally, morphologic abnormalities were observed in anterior stromal keratocytes, subepithelial and stromal nerves, and endothelium. The mean anterior and posterior keratocyte densities were statistically significantly higher than those in group B.

CONCLUSIONS

In addition to showing drug deposition does not seem to occur before 2 months of treatment and does not seem to be correlated with tear function. Although the clinical significance of morphologic changes induced by the drug is known and although deposition could not be detected before it was evident with slitlamp biomicroscopy, with some improvement in instrumentation, the authors believe that confocal microscopy will also prove to be useful in early diagnosis and in understanding the pathophysiology of amiodarone keratopathy. This may help grow insight to the mechanism of other, sometimes lethal, systemic side effects of this drug.

Drug-induced corneal complications

PURPOSE OF REVIEW

To review the common corneal manifestations of systemic medications in order to describe the characteristic clinical features associated with particular systemic drugs, the indications for drug cessation, and the risks for irreversible ocular toxicity.

RECENT FINDINGS

Systemic medications may reach the cornea via the tear film, aqueous humor, and limbal vasculature. The corneal changes are often the result of the underlying chemical properties of medications. Amphiphilic medications (amiodarone, chloroquine, suramin, clofazimine, etc.) may produce a drug-induced lipidosis and development of a vortex keratopathy. Antimetabolites (cytarabine) may lead to a degeneration of basal epithelial cells with formation of epithelial microcysts. Additionally, systemically administered medications and drug metabolites may lead to a stromal or endothelial deposition. Corneal changes may result in reduced visual acuity, photophobia, and ocular irritation, though these symptoms typically resolve following drug cessation. Corneal manifestations of systemic medications are often dose related, and may reflect the potential risk for lenticular or retinal changes.

SUMMARY

Corneal changes secondary to systemic medications may affect all layers of the cornea. While corneal deposition is typically not an indication for drug cessation, patients receiving particular medications should be monitored for symptoms related to corneal deposition as well as for signs of irreversible ocular toxicity.

Colchicine in tear fluid of treated patients with familial Mediterranean fever

PURPOSE

The study aimed to determine whether detectable concentrations of colchicine are present in the tear fluid of treated patients with familial Mediterranean fever (FMF) and thus demonstrate a possible route by which colchicine reaches the corneal surface.

METHODS

Tear fluid samples (50-100 microL) were collected from eight FMF patients on long-term colchicine treatment. Colchicine tear fluid concentrations were determined in all patients by radioimmunoassay using goat anticolchicine antibodies and [3H]colchicine (Dupont, Wilmington, DE).

RESULTS

Detectable concentrations of colchicine, with no apparent effect on the ocular surface, were found in all tear fluid samples (median, 0.46 ng/mL; range, 0.24-1.05 ng/mL).

CONCLUSIONS

This study provides evidence of the route by which colchicine, given systemically, reaches the corneal surface and thus gives credence to the possible inhibitory effect of this drug on corneal wound healing in the cases described in the literature.

Oligosymptomatic cornea verticillata in a heterozygote for Fabry disease: a novel mutation in the alpha-galactosidase gene

BACKGROUND

Fabry disease is an X-linked genetic disorder involving sphingolipid catabolism, which is caused by lysosomal alpha-galactosidase A deficiency. Ophthalmological findings such as corneal and lens opacities and conjunctival and retinal vessel abnormalities can be the only and/or the first recognizable symptoms, especially in heterozygous females.

METHODS

We report on a 34-year-old German woman with cornea verticillata. The alpha-galactosidase A activity was determined in leukocytes using a fluorescence substrate, and the sequence analysis of the alpha galactosidase A gene was performed with genomic DNA.

RESULTS

The alpha-galactosidase A activity in leukocytes was significantly low (0.24 nmol/min/mg protein; normal range, 0.4-1.2), which is compatible with a heterozygote for Fabry disease. The following sequence analysis revealed a heterozygous transition in position IVS5 + 2 T > C. Transition of thymine (T) to cytosine (C) affects the donor splice motive of exon 5 and most probably leads to an aberrant splicing procedure of the alpha-galactosidase A gene.

CONCLUSION

Our case emphasizes the importance of ophthalmological findings in Fabry disease. The subsequent biochemical and molecular analysis provides a secure diagnosis of female carriers of Fabry disease.

Visual functions and adverse ocular effects in patients with amiodarone medication

PURPOSE

To study visual functions and ocular adverse effects of long-term amiodarone medication.

METHODS

We performed an eye examination of 22 patients with long-term amiodarone medication. In addition to corrected visual acuity, colour vision was studied with the Standard Pseudoisochromatic Plates part 2 and Farnsworth-Munself 100 hue test. Contrast sensitivity was examined with the Pelli-Robson chart. Visual fields were tested by Goldmann and Friedmann perimetry.

RESULTS

Two patients with otherwise healthy eyes had abnormal blue colour vision test results. Otherwise colour vision, contrast sensitivity, and visual field test results were within normal range or could be explained by eye diseases such as cataract. Corneal drug deposits were found in 100% of the examined eyes. Slight anterior subcapsular lens opacities were found in 22.2%. Dry eyes were diagnosed in 9.1%. The eye fundi did not reveal any abnormalities that could be thought of as caused by amiodarone.

CONCLUSION

The slight blue colour vision defect found in two patients with otherwise healthy eyes might represent an early sign of the optic nerve impairment which is a rare complication of amiodarone medication. The number of corneal and lens changes as well as dry eyes were found at levels previously described.

In vivo confocal microscopy of patients with amiodarone-induced keratopathy

PURPOSE

To describe the corneal findings in patients with amiodarone-induced keratopathy by means of in vivo confocal microscopy.

METHODS

Twenty-two eyes of 11 patients (eight men and three women) receiving amiodarone therapy and 20 eyes of 10 healthy sex-and age-matched control subjects were selected for confocal microscopic examination. The patients were examined by use of a scanning slit corneal confocal microscope (Confoscan 2.0). Five complete scans of the entire cornea were performed for each eye with a total examination time of less than 5 minutes.

RESULTS

All patients receiving amiodarone showed the presence of high reflective, bright intracellular inclusions in the epithelial layers. These findings were more evident within the basal cell layers. In the eyes with advanced keratopathy (stages 2 and 3), bright microdots were detectable within the anterior and posterior stroma and on the endothelial cell layer. In the anterior stroma, the keratocyte density in the treated group was reduced compared with values of the control group (p < 0.001), and a markedly irregular aspect of the stromal nerve fibers was found. The main characteristic of this nerve irregularity was represented by the clew-shaped appearance of the nerve trunks.

CONCLUSION

Detailed examination of corneal structure by confocal microscopy shows that amiodarone keratopathy in long-term treated patients presents some findings that are consistent with higher toxicity than was expected and that involve the deep corneal layers.

Ocular side effects of amiodarone

Amiodarone is an effective antiarrhythmic agent. During therapy, intracytoplasmic lamellar deposits occur in the cornea, lens, retina, and optic nerve. The most common symptom, reported by 1.4-40.0% of patients, is colored rings around lights. The most common ocular finding is corneal epithelial opacities resembling a cat's whiskers in 70-100% of patients; however, lens opacities have been reported in 50-60% of patients. Neither type of deposit impairs visual acuity, and their presence is not contraindicative to continued amiodarone treatment. Retinopathy has, rarely, been reported in association with amiodarone treatment. Optic neuropathy in patients receiving the drug for various lengths of time has been reported as having incidences of 1.3% during the preceding 8 years and 1.76% during the preceding 10 years. Although a causal relationship is not well established, if optic neuropathy is observed, discontinuing or reducing the medication, if not life threatening, should be considered.

Retinal maculopathy possibly associated with amiodarone medication

A report is given on a 59-year-old female who acquired a wet maculopathy in her only seeing eye during amiodarone therapy given for a cardiac disorder. After withdrawal of the drug and subsequent central retinal laser therapy her visual acuity stabilized at 0.7 (follow-up time 6 years). With no similar reports in literature, it is suggested that the association between amiodarone therapy and the central retinopathy was accidental only.

Development of atypical amiodarone keratopathy in a corneal graft

The presence of fine epithelial deposits in a whorled pattern (cornea verticillata) as a consequence of treatment with amiodarone is well documented. We present a case of amiodarone keratopathy in a grafted cornea which is atypical in that the orientation of the pattern is rotated through nearly 90 degrees to that normally observed. This observation runs counter to the hypothesis that cornea verticillata is a manifestation of the line of lid closure. We speculate on the mechanism directing the migrational pathways of epithelial cells.

Amiodarone. An overview of its pharmacological properties, and review of its therapeutic use in cardiac arrhythmias

Amiodarone, originally developed over 20 years ago, is a potent antiarrhythmic drug with the actions of all antiarrhythmic drug classes. It has been successfully used in the treatment of symptomatic and life-threatening ventricular arrhythmias and symptomatic supraventricular arrhythmias. In patients with left ventricular dysfunction amiodarone does not usually produce any clinically significant cardiodepression and the drug has relatively high antiarrhythmic efficacy. Preliminary studies indicate that amiodarone may have a beneficial effect on mortality and survival in certain groups of patients with ventricular arrhythmias, an action probably related to both its antiarrhythmic and antifibrillatory effects. The adverse effect profile of amiodarone is diverse, involving the cardiac, thyroid, pulmonary, hepatic, gastrointestinal, ocular, neurological and dermatological systems. Interstitial pneumonitis and hepatitis are potentially fatal, but the vast majority of adverse events are less serious, and some may be dose dependent. Pretreatment monitoring, regular assessments and the use of minimum effective doses are, therefore, necessary. Thus, with appropriate monitoring to control its well recognised adverse effects amiodarone has an important place as an effective 'broad spectrum' antiarrhythmic drug which has, so far, been used when other treatments have proved ineffective. More recent preliminary data also suggest that it may also have a beneficial effect in the prevention of sudden death in some patients.

Long-term amiodarone therapy raises serum cholesterol

Serum total cholesterol and triglyceride levels were measured in 12 patients before and 3.6 and 9 months after treatment with amiodarone. In addition, we monitored serum T4, T3, reverse T3 and TSH levels. Amiodarone and its desethyl metabolite levels were measured on each occasion. Serum total cholesterol and T4 levels rose from 5.95 mmol/l, and 102.7 mmol/l respectively at baseline to 6.95 and 115.8 at 6 months and reverse T3 increased at 3, 6 and 9 months from baseline. Serum triglycerides did not change. No relationship existed between cholesterol, T4 and T3 and amiodarone (or its metabolite) levels nor between cholesterol and thyroid hormone levels. These data demonstrate that amiodarone therapy is associated with an elevation in serum cholesterol. This may have clinical implications in view of the current widespread use of the drug.

Long-term follow-up of amiodarone therapy in the young: continued efficacy, unimpaired growth, moderate side effects

Long-term follow-up data on young patients receiving amiodarone is lacking, especially in relation to growth and late side effects. The records of 95 young patients (mean age 12.4 years; range 3 weeks to 31.5 years) who received amiodarone were reviewed. Minimal follow-up time for those continuing to take amiodarone was 1.5 years; the mean duration of therapy was 2.3 years (maximal 6.5). The mean maintenance dosage was 7.7 (1.5 to 25) mg/kg body weight per day. Initial success (based on symptoms and 24 h electrocardiogram) was achieved in 23 of 34 patients with ventricular tachycardia, in 32 of 33 with atrial flutter and in 21 of 28 patients with supraventricular tachycardia. However, in 7 of 33 patients with atrial flutter, the arrhythmia returned after 6 months. Patient growth continued in the same percentiles achieved before amiodarone in all but eight patients, improving in six and worsening in two with severe underlying disease. Proarrhythmia occurred in three patients: one had torsade de pointes that disappeared when amiodarone administration was stopped; two with severe anatomic heart disease died suddenly during the loading period (one with atrial flutter and one with ventricular tachycardia). Side effects occurred in 28 (29%) of the 95 patients: keratopathy (in 11), abnormal thyroid function test (in 6), chemical hepatitis (in 3), rash (in 3), peripheral neuropathy (in 2), hypertension (in 1) and vomiting (in 1). All side effects disappeared when amiodarone was discontinued or the dose was reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Adverse effects of amiodarone. Pathogenesis, incidence and management

Amiodarone is an extremely effective antiarrhythmic agent for the treatment of both life-threatening ventricular arrhythmias and refractory supraventricular tachyarrhythmias. Subjective minor side effects are common with amiodarone but rarely require discontinuation of therapy and are often handled by dose reduction. Serious end-organ toxicity, including pulmonary fibrosis and drug-induced hepatitis, have been the most common indications for discontinuing amiodarone therapy in these patients.

A general overview of amiodarone toxicity: its prevention, detection, and management

Although amiodarone is a highly effective antiarrhythmic agent, it has a high incidence of side effects, some of which can be serious or even lethal. With close monitoring, side effects can be found in essentially all patients, but fortunately most of these are mild and well tolerated. Furthermore, many will respond to dosage reduction in a relatively short period of time, ie, days to weeks, which is remarkable considering the long period of time amiodarone has been shown to persist in tissues. There is reasonable evidence that toxicity, particularly the early toxic manifestations with large loading dosages, can be favorably modified by reducing the dosage. Similarly, reducing the maintenance dosage will, in most instances, reduce or eliminate most toxic manifestations. The mechanisms of toxic effects are uncertain, but suggestive evidence exists for and against both an immunologic reaction and an intracellular lysosomal lipoidosis. Principles of use of amiodarone should include individualizing administration of dosages for each patient due to the unusual pharmacokinetic properties of this drug and continuous long-term attempts at using the lowest effective dosage. There are no definite tests that predict amiodarone efficacy or toxicity, but the serum level can be used as a rough guide of absorption and distribution in the attempt to minimize the maintenance dosage. No guidelines regarding screening tests for toxicity can be made at this time since great variability in these tests has been reported, and no evidence exists for their benefit in preventing adverse effects to amiodarone. However, follow-up testing at the intervals noted in the package insert are reasonable and important. The possibility of interactions with drugs already reported and with others not yet reported should always be kept in mind, and appropriate monitoring for clinical evidence of toxicity due to the concomitantly used drugs should be undertaken. Amiodarone can have a tremendous beneficial effect in the proper circumstances, but it is a drug that should command utmost respect because of its side effects and requires constant vigilance from any physician wishing to use it.

New antiarrhythmic drugs

While controversy still exists as to the precise indications for the treatment of all forms of ventricular arrhythmia, advances in the number and, more importantly, type of antiarrhythmic drugs can provide the clinician with a rational basis for selecting antiarrhythmic drug therapy. A host of new agents with different pharmacokinetic and electrophysiological actions are now available, and can be compared or contrasted to conventional antiarrhythmic agents such as quinidine, procainamide, disopyramide, lignocaine (lidocaine) and bretylium. This review summarises the electrophysiological, haemodynamic, pharmacokinetic, and efficacy and safety data of mexiletine, tocainide, flecainide, encainide, propafenone, amiodarone, sotalol, pirmenol, cibenzoline (cifenline) and ethmozine (moracizine, moricizine), and aims to provide a basis on which clinicians can compare and contrast these agents and form an algorithm for selection of antiarrhythmic drug therapy in the treatment of patients with ventricular arrhythmias.

Amiodarone in the management of cardiac arrhythmias: current concepts

This article reviews current information on the clinical pharmacology, therapeutic utility, and adverse reactions of amiodarone, with emphasis on guidelines for its rational use.

Cutaneous ultrastructural changes and photosensitivity associated with amiodarone therapy

Amiodarone, an antiarrhythmic agent, is known to cause photosensitivity and cutaneous hyperpigmentation. Five patients taking this drug for periods of 1 to 48 months were studied. Skin biopsy specimens taken from a sun-exposed site were assessed by light microscopy, electron microscopy, and direct immunofluorescence. Three patients allowed comparative studies to be done on a biopsy specimen from non-sun-exposed skin. Light microscopy findings, including special stains, were not diagnostic of amiodarone-associated cutaneous changes. Electron microscopy, however, displayed distinctive intracytoplasmic inclusions in many cell types, some of which have not been reported previously. These inclusions represent phospholipid membranes associated with amiodarone or its metabolites as the result of a drug-induced lipidosis. Previous reports had postulated the inclusions were lipofuscin. Sun exposure may accelerate the formation of these intracellular deposits because they are more prominent in sun-exposed skin. Four of the above five cases, plus two additional patients, had symptoms compatible with a photosensitivity. Porphyrin assays were normal. Of the six patients phototested, three showed acute reactions to ultraviolet A (UVA) and ultraviolet B (UVB) and significant delayed reactions to UVA and/or UVB. The patients who had normal phototesting were on the drug for shorter periods than those with positive tests.

Impairment of colour vision associated with amiodarone keratopathy

Objective changes in colour vision have not been demonstrated previously in patients on long-term amiodarone therapy, although the occurrence of blurring of vision and seeing coloured haloes around lights has been widely reported. In a masked study, colour vision was assessed in 15 patients who had been treated with amiodarone for 16-72 months. Subjects with extensive corneal microdeposits (Miller stage 3) had worse colour vision than subjects with mild or moderate corneal changes (Miller stages 1 and 2) (P = 0.02), and higher serum concentrations of the metabolite desethlyamiodarone (P = 0.008). The only subject with marked asymmetry of corneal changes had a long-standing unilateral ptosis, suggesting that exposure to light might influence the development of corneal changes.

Amiodarone: pharmacology and antiarrhythmic and adverse effects

Amiodarone is a benzofuran derivative that has been effective for the treatment of both supraventricular and ventricular tachyarrhythmias. It has a large volume of distribution, moderate bioavailability and a long half-life. Its pharmacokinetics are not well understood and its tissue distribution is not typical of a 2-compartment model. Due to ocular, dermatologic, gastrointestinal, neurologic, cardiovascular, thyroid and pulmonary toxicity, amiodarone should be reserved for use in patients with refractory and/or life-threatening arrhythmias.

Important differences between short- and long-term hemodynamic effects of amiodarone in patients with chronic ischemic heart disease at rest and during ischemia-induced left ventricular dysfunction

To assess and compare the hemodynamic profile of short-and long-term amiodarone administration in the same set of patients and to investigate hemodynamic mechanisms responsible for the antianginal effect of this drug, 10 patients with documented coronary artery disease and stable angina pectoris were studied. Simultaneous right heart catheterization and equilibrium radionuclide angiocardiography were performed at rest and during exercise before therapy (control), after a 5 minute intravenous infusion of 7.5 mg/kg of amiodarone and after 21.0 +/- 4.3 days of peroral therapy (10 days 800 mg/day, 7 days 400 mg/day and then 200 mg/day). After acute drug administration, ejection fraction, stroke index and systolic blood pressure decreased, whereas heart rate, left and right ventricular filling pressures and systemic vascular resistance increased. These effects were reversed after long-term therapy; all measured values returned to control levels except for heart rate, which decreased below the control value, and right atrial pressure, which remained slightly elevated. Amiodarone drug levels decreased from 4.8 +/- 1.8 after intravenous infusion to 1.2 +/- 0.6 mg/liter after long-term therapy. After adjustment for hemodynamic changes at rest, there were still significant reductions in heart rate, mean arterial pressure and rate-pressure product during exercise. It is concluded that the marked negative inotropic effect of amiodarone administered acutely in the dose applied calls for cautious use of this drug when administered intravenously. In contrast, long-term oral amiodarone therapy seems hemodynamically safe, even in patients with moderately depressed left ventricular function.(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of superficial keratopathy

Corneal surface abnormalities are commonly encountered in ophthalmology and are manifestations of a wide range of underlying disease processes. The diversity of both clinical presentation and morphological appearance requires a systematic approach to the identification and management of these superficial corneal changes. Accurate diagnosis of superficial keratopathy requires skillful observation to seek the most characteristic clinical sign, a deductive thought process based on a knowledge of disease patterns, and occasionally the use of laboratory procedures to confirm the working diagnosis. We have classified changes of the corneal surface into five categories based on the clinical pattern (punctate, dendritic, plaque, vortex, and linear). We show how pattern recognition, with the aid of clinical presentation, history, and appropriate investigations, can lead to accurate diagnosis and initiation of proper management.

Amiodarone treatment of critical arrhythmias in children and young adults

The majority of sudden cardiac deaths in children occur in patients with prior arrhythmias and an abnormal heart. Amiodarone was given to 39 young patients (35 with an abnormal heart) with arrhythmias unresponsive to conventional treatment. Their age ranged from 6 weeks to 30 years with nine patients younger than 2 years of age. Atrial flutter was present in 16 patients, ventricular tachycardia in 14 patients and supraventricular tachycardia in 9 patients. The most common diagnosis (14 patients) was postoperative repair of congenital heart disease. The dose ranged from 2.5 to 21.6 mg/kg per day (mean 8.2). Elimination of arrhythmia (on 24 hour electrocardiography) occurred in 15 of 16 patients with atrial flutter, 11 of 14 with ventricular tachycardia and 5 of 9 with supraventricular tachycardia. Symptomatic side effects were: rash (three patients), headache (two patients), nausea (one patient) and peripheral neuropathy (one patient); seven patients had asymptomatic corneal microdeposits which normalized in all after the drug was discontinued. No side effects occurred in patients younger than 10 years of age. The following changed with treatment (p less than 0.05): heart rate decreased (three patients with atrial flutter and sick sinus syndrome required pacemaker implantation for bradycardia) and QTc increased; thyroxine (T4) and serum reverse triiodothyronine (T3) increased. During follow-up study (range 6 months to 3 years), 21 of the 39 patients continued to take amiodarone with complete control of arrhythmias, 9 were no longer taking the drug and 9 died (7 nonsudden and 2 sudden deaths). Amiodarone is an extremely effective treatment for infants and children with tachyarrhythmias resistant to conventional treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical use and pharmacology of amiodarone

Amiodarone, an investigational drug in the United States, has had considerable use in this country and worldwide in the treatment of cardiac arrhythmias. This article reviews the clinical pharmacology of this potentially useful antiarrhythmic agent.