Teratogenicities of ophthalmic drugs. I. Antiviral ophthalmic drugs

Treatments for Ocular Diseases in Pregnancy and Breastfeeding: A Narrative Review

Pregnancy is a medical condition in which the physiological changes in the maternal body and the potential impact on the developing fetus require a cautious approach in terms of drug administration. Individual treatment, a thorough assessment of the extent of the disease, and a broad knowledge of the therapeutic options and different routes of administration of ophthalmic drugs are essential to ensure the best possible results while minimizing risks. Although there are currently several routes of administration of drugs for the treatment of eye diseases, even with topical administration, there is a certain amount of systemic absorption that must be taken into account. Despite continuous developments and advances in ophthalmic drugs, no updated data are available on their safety profile in these contexts. The purpose of this review is both to summarize the current information on the safety of ophthalmic treatments during pregnancy and lactation and to provide a practical guide to the ophthalmologist for the treatment of eye diseases while minimizing harm to the developing fetus and addressing maternal health needs.

Antiviral treatment and other therapeutic interventions for herpes simplex virus epithelial keratitis

BACKGROUND

Eye disease due to herpes simplex virus (HSV) commonly presents as epithelial keratitis which, though usually self-limiting, may persist or progress without treatment.

OBJECTIVES

To compare the relative effectiveness of antiviral agents, interferon, and corneal debridement in the treatment of HSV epithelial keratitis.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 12), PubMed (January 1946 to 31 December 2014), EMBASE (January 1980 to 31 December 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to 31 December 2014), System for Information on Grey Literature in Europe (OpenGrey) (January 1995 to 31 December 2014), BIOSIS (January 1926 to 5 May 2014), Scopus (January 1966 to 31 December 2014), Japan Science and Technology Institute (J-Global) (January 1975 to 31 December 2014), China National Knowledge Infrastructure (CNKI) (January 1979 to 31 December 2014), British Library's Electronic Table of Contents (Zetoc) (January 1993 to 7 May 2014). We looked for trials listed on the the metaRegister of Controlled Trials (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en), Chinese Clinical Trial Registry, the U.S. Food and Drug Administration (FDA) (www.fda.gov/), National Institute for Health and Clinical Excellence (NICE) (www.

EVIDENCE

nhs.uk) and the European Medicines Agency (EMA) (www.ema.europa.eu/ema/) as of 31 December 2014. There were no language or date restrictions in the search for trials. We also culled literature digests and conference proceedings as of 15 April 2014. There were no language or date restrictions in the search for trials.

SELECTION CRITERIA

Randomised and quasi-randomised trials of HSV dendritic or geographic epithelial keratitis were included that reported the proportion of eyes healed at one week, two weeks, or both after enrolment.

DATA COLLECTION AND ANALYSIS

We tabulated data on study characteristics, risk of bias, and outcomes and used direct comparisons to estimate a risk ratio (RR) and, when feasible, a hazard ratio (HR) with a 95% confidence interval (CI). Heterogeneity was assessed by an inconsistency index. A multiple treatment comparison meta-analysis consolidated direct and indirect comparisons of relative healing at 14 days.

MAIN RESULTS

One hundred thirty-seven studies involving 8333 eyes met the inclusion criteria. Placebo-controlled studies were heterogeneous in comparison with idoxuridine (RR 1.74; 95% CI 1.03 to 2.91) and few in number for vidarabine (RR 1.81; 95% CI 1.09 to 3.01), interferon (RR 1.32; 95% CI 1.06 to 1.64), and debridement. Vidarabine (RR 1.13; 95% CI 1.02 to 1.25), trifluridine (RR 1.30; 95% CI 1.18 to 1.43), acyclovir (RR 1.23; 95% CI 1.14 to 1.34), and brivudine (RR 1.34; 95% CI 1.18 to 1.51) were more effective than idoxuridine. Trifluridine (RR 1.17; 95% CI 1.03 to 1.32) and acyclovir (RR 1.11; 95% CI 1.03 to 1.19) were more effective than vidarabine. No significant differences in healing emerged among trifluridine, acyclovir, brivudine, and foscarnet although few studies compared brivudine or foscarnet with other antivirals. Any potential advantage of ganciclovir compared to acyclovir was mitigated by study heterogeneity and possible publication bias. Only one study evaluated the joint use of two topical antivirals. In a limited number of studies, oral acyclovir (RR 0.92; 95% CI 0.79 to 1.07) or the combination of oral acyclovir with a topical antiviral (RR 1.36; 95% CI 0.68 to 2.74) appeared as effective as a single topical antiviral agent. Compared to topical antiviral monotherapy, the combination of an antiviral with either interferon or debridement had inconsistent effects on expediting healing and improving outcome.

AUTHORS' CONCLUSIONS

Placebo-controlled studies of HSV epithelial keratitis are limited to superseded interventions. Trifluridine and acyclovir are more effective than idoxuridine or vidarabine and similar in therapeutic effectiveness. Brivudine and foscarnet do not substantially differ in effectiveness from trifluridine or acyclovir. Ganciclovir is at least as effective as acyclovir. The addition of interferon to a nucleoside antiviral agent and the combination of debridement with antiviral treatment need to be further assessed to substantiate any possible advantage in healing.

Antiviral treatment and other therapeutic interventions for herpes simplex virus epithelial keratitis

BACKGROUND

Eye disease due to herpes simplex virus (HSV) commonly presents as epithelial keratitis.

OBJECTIVES

To compare the relative effectiveness of antiviral agents, interferon, and corneal débridement in the treatment of acute HSV epithelial keratitis.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2010, Issue 4), MEDLINE (January 1950 to October 2010), EMBASE (January 1980 to October 2010), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to October 2010), Zetoc (British Library's Electronic Table of Contents), System for Information on Grey Literature in Europe (openSIGLE), Biosciences Information Service (BIOSIS), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), Japan Information Center of Science and Technology (JICST-EPlus), and China Academic Journals database (CAJ) via China National Knowledge Infrastructure (CNKI) with citations confirmed using China/Asia On Demand (COAD). There were no language or date restrictions in the search for trials. All databases except CNKI and COAD were last searched on 27 October 2010, CNKI and COAD were searched on 1 April 2010. We also searched literature digests, conference proceedings and reference lists.

SELECTION CRITERIA

Of 152 eligible studies,106 comparative treatment trials involving 5872 eyes with dendritic or geographic epithelial keratitis were analysed for corneal healing over two weeks.

DATA COLLECTION AND ANALYSIS

Interventions were compared at 14 days after trial enrolment by calculating a risk ratio (RR) that was adjusted with indirect RR, assessed by an inconsistency index (I(2) ) and supplemented by a seven-day RR and a hazard ratio (HR).

MAIN RESULTS

Idoxuridine, though uncertainly better in healing outcome than control because of few trials with 14-day follow up, allowed earlier corneal re-epithelialisation. Vidarabine resulted in a significantly better outcome than placebo in one trial (RR 1.96; 95% CI 1.10 to 3.49). Compared to idoxuridine, in combined direct and indirect analyses, vidarabine (RR 1.11; 95% CI 1.03 to 1.19), trifluridine (RR 1.31; 95% CI 1.20 to 1.42), acyclovir (RR 1.23; 95% CI 1.16 to 1.31), brivudine (RR 1.38; 95% CI 1.18 to 1.61), and ganciclovir (RR 1.40; 95% CI 1.25 to 1.57) were significantly more effective. Trifluridine (RR 1.12; 95% CI 1.04 to 1.21) and acyclovir (RR 1.11; 95% CI 1.05 to 1.19) appeared more effective than vidarabine. No significant differences were found in comparisons between acyclovir, trifluridine and brivudine. The comparison of ganciclovir to acyclovir was limited by heterogeneity and possible publication bias. The joint use of two topical antivirals (RR 1.00; 95% CI 0.89 to 1.12) and the use of oral acyclovir alone (RR 0.92; 95% CI 0.79 to 1.07) or combined with a topical antiviral (RR 1.08; 95% CI 0.99 to 1.17) appeared as effective as topical antiviral therapy. Compared to antiviral monotherapy, the combination of an antiviral with interferon (RR 1.03; 95% CI 0.99 to 1.07) or with débridement (RR 1.04; 95% CI 0.95 to 1.14) did not yield significantly better outcomes but may have accelerated healing. The corneal epithelial healing outcome was improved when antiviral therapy was added to débridement (RR 1.21; 95% CI 1.04 to 1.42).

AUTHORS' CONCLUSIONS

Trifluridine and acyclovir are more effective than idoxuridine or vidarabine, and similar in therapeutic effectiveness. Brivudine and ganciclovir are at least as effective as acyclovir. While not improving outcome, the combination of interferon and an antiviral agent may speed healing. The effectiveness of corneal epithelial débridement is improved by an antiviral agent.

Structure-activity relationships and conformational features of antiherpetic pyrimidine and purine nucleoside analogues. A review

A rational approach to the design of antiherpetic nucleoside analogues is based in part on the broad specificity of virus-coded thymidine kinases. Herpes virus thymidine kinase 'activates' many 5-substituted 2'-deoxyuridines, analogues of thymidine (e.g., idoxuridine, trifluridine, edoxudine, brivudine), 5-substituted arabinofuranosyluracil derivatives (e.g., 5-Et-Ara-U, BV-Ara-U, Cl-Ara-U), acyclonucleosides of guanine (e.g., aciclovir, ganciclovir, penciclovir), and purine nucleosides with the pentafuranosyl ring replaced by a cyclobutane ring (e.g., cyclobut-G, cyclobut-A). Activation involves selective, and frequently regiospecific, phosphorylation of these analogues to the 5'-monophosphates. These are further phosphorylated by cellular enzymes to the 5'-triphosphates, which are usually competitive inhibitors of the viral-coded DNA polymerases. Some analogues are also incorporated into viral, and to a lesser extent cellular, DNA. A recent, unusual, exception is human cytomegalovirus, which does not code for a thymidine kinase, but for a protein with the sequence characteristics of protein kinase and which phosphorylates ganciclovir to its 5'-monophosphate. The interaction of the analogues with cellular catabolic enzymes such as uridine and thymidine nucleoside phosphorylases is also discussed, as is the relationship between physicochemical properties (configuration, conformation, electronic and hydrophobic parameters) and antiviral activities, with particular reference to those drugs that are licensed, or under consideration, for clinical use.

Side effects in the treatment of herpetic keratitis

Various side effects due to antiherpetic drugs observed in the last ten years in our department were studied. A total of 132 patients were treated with 5-iodo-2'-deoxyuridine (IDU), 69 with trifluorothymidine (F3T), 58 with acyclovir (ACV) and 33 with adenine arabinoside (ara-A). Patch tests were routinely done when patients exhibited contact dermatitis. Of the patients treated with IDU, 3 (2.3%) showed contact dermatitis, 2 (1.5%) follicular conjunctivitis and 1 (0.8%) punctate keratopathy. Of the patients treated with F3T, 7 (10.1%) exhibited contact dermatitis and 1 (1.4%) follicular conjunctivitis. In the group treated with ACV, 2 (3.4%) patients showed punctate keratopathy. The patients who received ara-A did not show any side effects. We found that F3T caused contact dermatitis more frequently in Japanese people than Europeans. These side effects were resolved by switching to another anti-herpetic drug without the occurrence of cross-allergy. Therefore, switching to another drug is strongly recommended when patients exhibit side effects in the treatment of herpetic keratitis. Other complications were allergy to atropine and to drug preservative.

A preliminary study of corneal penetration of 125I-labelled idoxuridine liposome

We compared corneal penetration of idoxuridine (IDU) to liposome-encapsulated IDU. Liposomes of phosphatidic acid, phosphatidyl choline, and alpha-tocopherol in a molar ratio 1:8:1 were prepared using the reverse phase evaporation method. New Zealand albino rabbits received either 0.1% solution of I125-labelled aqueous IDU or liposome-encapsulated IDU topically every 2 min for 6 min. Corneal, aqueous, and vitreous samples were assayed for I125 radioactivity at 15 min and at 1, 2, 3, and 6 h following drug application. Our results indicated that corneal penetration of liposomal IDU was significantly increased over the regular form of the drug for a time interval of 6 h.

Combination chemotherapy: interaction of 5-methoxymethyldeoxyuridine with trifluorothymidine, phosphonoformate and acycloguanosine against herpes simplex viruses

Methoxymethyldeoxyuridine (MMUdR) when used in combination with either trifluorothymidine (F3TdR) or phosphonoformate (PFA) showed synergistic activity against herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2) in vitro, whereas MMUdR and acycloguanosine (ACG) combination was antagonistic against herpes viruses. HSV-1 mutants resistant to ACG, arabinofuranosyladenine (Ara-A), MMUdR or PFA were isolated. Drug-resistant HSV-1 virus mutants were analyzed for cross sensitivity to ACG, Ara-A, F3TdR, MMUdR, MMUdR-5'-monophosphate (MMUdR-MP) and PFA. The Ara-A-resistant (Ara-AR) virus exhibited 3-fold resistance to MMUdR-MP (ID50 = 105 microM). The ACG-resistant (ACGR) mutant was 160-fold less sensitive to MMUdR (ID50 greater than 1138 microM). The MMUdR-resistant (MMUdRR) mutant remained sensitive to all other antiviral drugs in vitro. Ara-A provided protection against HSV-1 encephalitis in immunosuppressed mice inoculated with a low dose (200 PFU/mouse) of MMUdRR virus or wild-type HSV-1. F3TdR decreased incorporation of tritiated deoxyuridine [( 3H]UdR) in RK-13 cells by 50% at 0.068 microM. Under similar conditions, MMUdR (up to 600 microM) and PFA (up to 208 microM) were without effect on incorporation of [3H]UdR into DNA. In combination chemotherapy experiments, MMUdR (up to 300 microM) used along with F3TdR (up to 1.08 microM) neither decreased nor enhanced cytotoxicity of F3TdR as measured by incorporation of [3H]UdR into cellular DNA. Similarly, MMUdR (up to 300 microM) in combination with PFA (up to 166 microM) was nontoxic to host cells.

Corneal epithelial dysplasia after trifluridine use

Prolonged topical trifluridine treatment of herpes simplex keratitis in three elderly patients produced slightly raised dysplastic corneal epithelial lesions. The involved epithelium had a ground-glass appearance and exhibited opaque cells, edema, and spindle-shaped surface cells. Histopathology demonstrated severe cellular atypism, loss of cell polarity, dyskeratosis, parakeratosis, and a few mitotic figures. The pathological change was apparently intraepithelial. After scraping, the edema and opaque cells in the regenerated epithelium gradually disappeared in 3-4 months on cessation of trifluridine therapy. In one patient recurrence of dendritic keratitis, 5 weeks after scraping, was treated by topical bromovinyldeoxyuridine eye drops. Since severe epithelial dysplasia may represent a precancerous condition, prolonged use of trifluridine should be avoided.

Trifluridine: a review of its antiviral activity and therapeutic use in the topical treatment of viral eye infections

Trifluridine (trifluorothymidine) is an antiviral agent for topical use in the eye, and is structurally related to idoxuridine. In vitro studies have shown that it effectively inhibits the replication of herpes simplex virus type 1, which causes primary keratoconjunctivitis and recurrent epithelial keratitis in man. In masked comparative studies, predominantly in patients with dendritic ulcers, trifluridine 1% solution was effective in over 90% of patients; in such studies it was comparable with vidarabine in treating dendritic ulcers, and was at least as effective as, and in some studies more effective than, idoxuridine. The drug was also effective in treating a small number of patients with geographic ulcers (sometimes associated with the usage of topical corticosteroids), and this could be an important advantage if confirmed in further well-designed studies. However, experience at present is too limited to reliably determine the usual response rate in this difficult therapeutic area. In open studies the drug proved to be particularly useful in treating ulcers previously unresponsive to idoxuridine or vidarabine, and in treating patients intolerant of idoxuridine, with a high success rate and minimal side effects being reported. The role of trifluridine in treating deep stromal disease, uveitis, or adenovirus kerato-conjunctivitis has not been established. The drug is well tolerated and cross-hypersensitivity and cross-toxicity between trifluridine, idoxuridine and vidarabine are rare. Thus, trifluridine is an effective alternative to the drugs available for treating herpetic keratitis, and seems especially useful in 'difficult' cases.

Combination chemotherapy: interaction of 5-methoxymethyldeoxyuridine with adenine arabinoside, 5-ethyldeoxyuridine, 5-iododeoxyuridine, and phosphonoacetic acid against herpes simplex virus types 1 and 2

The antiviral activity of 5-methoxymethyl-2'-deoxyuridine (MMUdR) was compared with that of 5-iodo-2'-deoxyuridine (IUdR), 5-ethyl-2'-deoxyuridine (EtUdR), adenine arabinoside (Ara-A), and phosphonoacetic acid (PAA) against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). MMUdR was more potent than Ara-A and PAA but less active than EtUdR and IUdR against HSV-1 in rabbit kidney (RK-13) cells. In Vero cells, the antiviral activities of MMUdR, Ara-A, and PAA against HSV-1 were of the same order of magnitude. The antiviral potency against HSV-2 varied with the strain of virus used. All strains of HSV-2 were markedly inhibited by EtUdR and IUdR and to a lesser degree by PAA. However, considerable variation was noticed in the susceptibility of HSV-2 strains to Ara-A and MMUdR. Interaction of MMUdR with Ara-A, EtUdR, IUdR, and PAA was investigated by the method of response isobolograms. MMUdR showed synergistic activity in combination with Ara-A and PAA but antagonistic activity in combination with EtUdR and IUdR against herpesviruses. Minimum toxic dose (concentration required to produce definite evidence of microscopic cytotoxicity in rapidly growing RK-13 cells) was determined for each compound and was found to be 512, 172, 64, 8, and less than 0.5 microgram/ml for MMUdR, PAA, Ara-A, EtUdR, and IUdR, respectively. MMUdR was found to have the maximum antiviral index against HSV-1 (512) and HSV-2 strains X-265 (102) and ATCC (85). Antiviral index was defined as the minimum toxic dose divided by the dose that reduced plaque numbers by 50%.

Trifluorothymidine and idoxuridine therapy of ocular herpes

In a coded study, we treated 40 patients who had active herpes simplex corneal ulcers with either 1% trifluorothymidine (F3T) or 0.1% idoxuridine (IDU) drops; we treated 15 similarly afflicted patients, who had failed on IDU or vidarabine, with open 1% F3T drops. All dosages were at therapeutically recommended frequency. In the coded study there was no statistically significant difference between the drugs in rate of healing; mean initial ulcer size in both groups was approximately 7 mm2 and mean healing time was approximately 5.5 days. There was a significant difference, however, in the chances of successful healing; 96% of all F3T treated eyes and only 75% of IDU treated eyes healed completely within 14 days. In the open study, 87% of patients healed completely on F3T eyedrops. Although an insufficient number of patients were on concomitant coricosteroid therapy to provide statistical analysis, F3T-corticosteroid treated eyes (eight masked and open) all healed. The one IDU-corticosteroid treated eye in the masked study failed to heal.

The effect of vidarabine on the development of the offspring of rats, rabbits, and monkeys

The effect of vidarabine, a new antiviral agent, on the offspring of rats, rabbits, and monkeys was studied by varying routes of administration during several periods of gestation. Vidarabine demonstrated a dose-related teratogenic effect in rats when given parenterally at doses of 30 mg/kg and greater. The drug was also teratogenic in the rabbit at dosages of 5 mg/kg and greater by the parenteral route or when applied topically in 10% concentration to 5 or 10% of the body surface area. The pattern of malformation was similar in the two species, and consisted of multiple, severe abnormalities of the head, trunk, and limbs. The drug had no demonstrable teratogenic effect in a limited study in the rhesus monkey; nor were there adverse effects on the offspring when it was applied intravaginally to pregnant rats in the perinatal period.

Herpes simplex keratitis

This article reviews the current concepts for the diagnosis and treatment of Herpes simplex keratitis and its complications, discussing characteristics of the virus, the prevalence of the disease, chemical and clinical differentiation between Types I and II Herpesvirus hominis, and the many clinical presentations of Type I disease. The antiviral agents commonly in use are reviewed, covering the historical development of the drugs, indications for their use and the associated toxic and untoward reactions. An outline for the medical treatment of the different forms of Herpes simplex keratitis is given, as well as the indications for surgical intervention in the treatment of the disease. The surgical complications and results following keratoplasty are discussed.