China
Africa
Explore chapters and articles related to this topic
Treatment of Retinitis Induced by Cytomegalovirus Using Intravitreal Fomivirsen (ISIS 2922)
Published in Eric Wickstrom, Clinical Trials of Genetic Therapy with Antisense DNA and DNA Vectors, 2020
Toxicological studies in mice of one-month, repeat-dose intravenous fomivirsen at 0.2-50 μg/kg every other day produced a toxicological profile similar to those of other phosphorothioate oligonucleotides. Next it was appropriate to evaluate its potential toxicological effects after intravitreal administration. The effects of single-intravitreal doses ranging from 16.5 to 330 μg/eye yielding theoretical vitreal concentrations as high as 40 mM were evaluated in the pigmented rabbit. The drug induced a dose dependent inflammatory response in the eye. At lower doses and earlier time points, the ciliary body was the primary structure affected. At doses that resulted in theoretical concentrations of 20 and 40 μΜ, other ocular structures were affected. In animals treated with 40 μΜ drug, retinal degeneration was observed, probably secondary to inflammation (Fomivirsen Investigator's Brochure, 1996).
Bevacizumab in the treatment of ocular disease
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
Robert L Avery, Dante J Pieramici
Bevacizumab has demonstrated an ability to have a profound biologic effect on ocular neovascularization and macular edema. Intravitreal administration seems to provide a similar biologic effect to intravenous administration, at lower cost and with less risk of systemic side-effects. Due to its low cost, it may become a standard therapy in many parts of the world where other agents are prohibitively expensive.41 However, although intravitreal bevacizumab appears to be safe in the short term in the few studies reported to date, its long-term safety is unknown, and will likely determine its role in our armamentarium for the treatment of ocular diseases.
Trimethoprim and Trimethoprim–Sulfamethoxazole (Cotrimoxazole)
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Jason A. Trubiano, M. Lindsay Grayson
Intravitreal administration has been used only in a small number of cases, generally in conjunction with steroid therapy, as a weekly or biweekly dose until clinical improvement. No obvious retinal toxicity has been noted (Choudhury et al., 2015).
Hyaluronic acid-based nanoparticles to deliver drugs to the ocular posterior segment
Published in Drug Delivery, 2023
Posterior segment illness is a leading cause of irreversible visual loss that must be addressed (Meza-Rios et al., 2020; Varela-Fernández et al., 2020). Although the eye is an easy-to-reach body part, drug administration to the posterior portion remains a challenge (Alshaikh et al., 2022). Topical application is a convenient and safe method for delivering ocular medications to the surface of the eye (Wei et al., 2023). Due to the various eye barriers, it is still challenging for topical administration to efficiently transfer drugs to the posterior of the eye. Intravitreal administration, compared with systemically and topically delivered agents, can directly reach intraocular lesions without systemic toxicity. Frequent injection to maintain the concentration of the drugs in the vitreous may lead to an increased risk of complications, such as increased intraocular pressure, endophthalmitis, vitreous hemorrhage, and cataract (Patel et al., 2022). The research and development of continuous-release formulations and intravitreal implants are two critical topics for reducing the quantity and frequency of vitreous cavity injections (Cabrera et al., 2019). To insert vitreous implants, invasive surgical operations are needed, and nonbiodegradable materials may require a second operation for removal. Nanocontrolled delivery technology can improve pharmacokinetics to prolong and monitor the release of medicines by increasing their solubility, bioavailability, and stability (Nayak & Misra, 2018; Cabrera et al., 2019).
Long-acting ocular drug delivery technologies with clinical precedent
Published in Expert Opinion on Drug Delivery, 2022
Matthew N. O’Brien Laramy, Karthik Nagapudi
Intravitreal administration involves injection or insertion through the sclera into the vitreous humor [36,37]. With intravitreal administration, the drug is bioavailable in the vitreous fluid, without permeation through the conjunctiva or sclera from outside the eye or through the lens from the anterior chamber. Intravitreal injections are typically performed with topical anesthesia, aseptic techniques, and a 30-gauge or smaller diameter needle. Larger gauge needles (up to 27-gauge) may be used to deliver viscous solutions, suspensions, or implants, but can increase the risk of post-injection reflux (i.e. fluid leakage from the injection site). Injections are typically administered into the pars plana to avoid vision impairment, with a 1/2-inch to 5/8-inch needle. Safe injection volumes are typically limited to 50 to 100 μL to avoid swelling or paracentesis (i.e. perforation). The injection volume accuracy can be influenced by the syringe design and injection procedure, and must be carefully monitored to avoid adverse effects [38]. In clinical practice, regular intravitreal injections are difficult to maintain due to their invasiveness and potential complications, which include retinal hemorrhage and detachment, inflammation, and elevated intraocular pressure [39–45].
Progress in the pharmacotherapy of uveitis: the art of personalized care
Published in Expert Opinion on Pharmacotherapy, 2022
Shivam H. Patel, Aditya Belamkar, Amir R. Hajrasouliha, Denis Jusufbegovic, Thomas A. Ciulla
Methotrexate inhibits dihydrofolic acid reductase which blocks folic acid metabolism and thymidine synthesis [1,8]. It has been found to be a very effective treatment for a spectrum of noninfectious uveitis subtypes and may even have superior effectiveness and tolerability as compared to other antimetabolites [8]. In addition, methotrexate may be specifically indicated in pediatric populations with refractory uveitis [5]. It may be given orally, intramuscularly, intravenously, or intravitreally [1]. The oral dose is typically started between 7.5 and 15 mg once a week and may be raised to 20–25 mg depending upon the severity of the inflammation [1,5]. In comparison, intramuscular administration is dosed at 20 mg or above and recommended for those who suffer from gastrointestinal distress due to oral administration [1]. Intravenous and intravitreal administration is typically reserved for very severe or refractory presentations [1]. In a multicenter retrospective case series of 30 patients with NIU, intravitreal methotrexate injected at a dose of 400 ug significantly improved visual acuity, CME, and allowed for reduction of immunosuppressive therapy. In addition, approximately three-fourths of patients entered an extended period of remission which lasted up to 18 months [30].