Preventive effect of lacrimal occlusion on topical timolol-induced bronchoconstriction in asthmatics

Beta-blockers in asthma: myth and reality

Introduction: Patients with asthma often have important co-morbidities which reduce the likelihood of gaining optimal asthma control. Beta2-blockers are commonly prescribed for the treatment of different clinical indications, including coronary artery disease, cardiac arrhythmia, arterial hypertension, heart failure and glaucoma. Areas covered: The aim of this reviw is to summarize current evidence on the effect of systemic and local β-blockers on asthma outcomes based on their pharmacologic properties,and to help clinicians when prescribing for patients with asthma and co-morbidities. Current data suggest that risk of asthma worsening from systemic and local use of non-selective β-blockers outweighs any potential benefits for their clinical indications. Recent studies confirm that topical and systemic prescription of cardio-selective β-blockers is not associated with a significant increased risk of moderate or severe asthma exacerbations. Expert opinion: Non-selective β-blockers should not be prescribed for the management of comorbidities in patients with asthma while cardio-selective β-blockers, preferably in low doses, may be used when strongly indicated and other therapeutic options are not available. More prospective real-life studies are needed to evaluate the risk of long-term use of β-blockers in patients with asthma.

Barriers to glaucoma drug delivery

Topical medications remain the mainstay of glaucoma treatment. This review will aim to cover the pharmacokinetics of topically applied drops, the ocular barriers to drug delivery, and the role of ophthalmic drug formulation in enhancing drug delivery to the target tissue while minimizing side effects and increasing patient compliance. Recent advances in surgical techniques, therapeutic approaches, and material sciences have produced exciting new therapies for ocular diseases. The development of new vehicles and drug formulations that require less patient compliance is also discussed, as are the routes of drug delivery for neuroprotection.

Ocular drug delivery

Drug delivery to the eye is hampered by anatomical factors, including the corneal epithelium, the blood-aqueous barrier and the blood-retinal barrier. This review aims to outline the major routes of ocular drug delivery, including systemic, topical, periocular and intravitreal. The pharmacokinetics, the disadvantages and the clinical relevance of these drug delivery routes have been emphasised. Recent advances in surgical techniques, therapeutic approaches and material sciences have produced exciting new therapies for ocular diseases. The role of ophthalmic drug formulation in targeting the desired ocular tissue and enhancing drug delivery by the chosen route whilst minimising side effects is also discussed.

Glaucoma Medications

As with many diseases, glaucoma increases in frequency in older populations, and is very often encountered in patients taking multiple medications. While the exact mechanism of glaucomatous optic neuropathy (GON) is not known, intraocular pressure (IOP) is thought to be central to the process, and reducing IOP is the only known effective treatment. The newer definition of glaucoma is an IOP-sensitive optic neuropathy. While large, controlled studies have indicated that reducing IOP will slow the progression of disease, the contributions of other conditions and medications have not been adequately studied. As the adverse effect profiles of medical therapies for glaucoma have improved, use of these agents has increased greatly. This has resulted in a large number of older patients taking glaucoma medications. Since topical medications can easily be overlooked in a medical history, and are for the most part well tolerated, systemic complications from these agents can be missed. In addition to being a common disease requiring treatment, glaucoma is also a model system for other degenerative diseases, and many of the concepts originally developed in relation to neurodegenerative diseases such as Alzheimer's disease are under investigation for glaucoma. These include approaches targeted towards neuroprotection and excitotoxicity.