Management and outcome of topical beta-blocker-induced atrioventricular block

Reversible Causes of Atrioventricular Block

Atrioventricular blocks may be caused by a variety of potentially reversible conditions, such as ischemic heart disease, electrolyte imbalances, medications, and infectious diseases. Such causes must be always ruled out to avoid unnecessary pacemaker implantation. Patient management and reversibility rates depend on the underlying cause. Careful patient history taking, monitoring of vital signs, electrocardiogram, and arterial blood gas analysis are crucial elements of the diagnostic workflow during the acute phase. Atrioventricular block recurrence after the reversal of the underlying cause may pose an indication for pacemaker implantation, because reversible conditions may actually unmask a preexistent conduction disorder.

Synergistic Effect of Acetazolamide-(2-hydroxy)propyl β-Cyclodextrin in Timolol Liposomes for Decreasing and Prolonging Intraocular Pressure Levels

The purpose of this study was to design, for the first time, a co-loaded liposomal formulation (CLL) for treatment of glaucoma including timolol maleate (TM) in the lipid bilayer and acetazolamide (Acz)-(2-hydroxy)propyl β-cyclodextrin (HPβCD) complexes (AczHP) solubilized in the aqueous core of liposomes. Formulations with TM (TM-L) and AczHP (AczHP-L), separately, were also prepared and characterized. A preliminary study comprising the Acz/HPβCD complexes and their interaction with cholesterol (a component of the lipid bilayer) was realized. Then, a screening study on formulation factors affecting the quality of the product was carried out following the design of the experiment methodology. In addition, in vitro release and permeation studies and in vivo lowering intraocular pressure (IOP) studies were performed. The results of the inclusion complexation behavior, characterization, and binding ability of Acz with HPβCD showed that HPβCD could enhance the water solubility of Acz despite the weak binding ability of the complex. Ch disturbed the stability and solubility parameters of Acz due to the fact of its competence by CD; thus, Chems (steroid derivative) was selected for further liposome formulation studies. The optimization of the lipid bilayer composition (DDAB, 0.0173 mmol and no double loading) and the extrusion as methods to reduce vesicle size were crucial for improving the physico-chemical properties and encapsulation efficiency of both drugs. In vitro release and permeation studies demonstrated that the CLL formulation showed improvement in in vitro drug release and permeation compared to the liposomal formulations with a single drug (TM-L and AczHP-L) and the standard solutions (TM-S and AczHP-S). CLL showed high efficacy in reducing and prolonging IOP, suggesting that the synergistic effect of TM and Acz on aqueous humor retention and the presence of this cyclodextrin and liposomes as permeation enhancers are responsible for the success of this strategy of co-loading for glaucoma therapy.

Reversible Causes of Atrioventricular Block

Atrioventricular blocks may be caused by a variety of potentially reversible conditions, such as ischemic heart disease, electrolyte imbalances, medications, and infectious diseases. Such causes must be always ruled out to avoid unnecessary pacemaker implantation. Patient management and reversibility rates depend on the underlying cause. Careful patient history taking, monitoring of vital signs, electrocardiogram, and arterial blood gas analysis are crucial elements of the diagnostic workflow during the acute phase. Atrioventricular block recurrence after the reversal of the underlying cause may pose an indication for pacemaker implantation, because reversible conditions may actually unmask a preexistent conduction disorder.

Management of glaucoma in pregnancy - balancing safety with efficacy

Glaucoma and pregnancy is an uncommon combination, but it constitutes a very challenging situation for the treating doctor. The challenge is not only controlling the intraocular pressure and preventing glaucoma progression in the mother, but also having to deal with her mental stress and anxiety regarding the safety of her child. The situation is further worsened by the lack of definite guidelines as to how to deal with such patients. Relative rarity of glaucoma in this population restricts any large prospective randomized clinical trials or any large systematic studies. Moreover, none of the existing anti-glaucoma medications is absolutely safe in pregnancy. Current practice patterns depend on some case reports, a few observational studies and a few animal studies that attempt at determining the safety and efficacy of the available medicines. These are then prescribed on the basis of their relative safety in any particular stage of pregnancy or lactation. Newer medications that were released recently in 2018, such as Vyzulta and Rhopressa, presently have limited data to support their safety for use during pregnancy. Laser trabeculoplasty, conventional filtration surgery (of course without anti-metabolites), and minimally invasive glaucoma surgery represent a few non-pharmacological management options. Surgical procedures such as trabeculectomy and tube-shunts or collagen matrix implants, and newer minimally invasive glaucoma surgery procedures such as the gelatin stents are currently being explored and may prove to be viable solutions for severe glaucoma during pregnancy, although they too have their own inherent drawbacks. Management of glaucoma during pregnancy and lactation requires careful consideration of the disease status, gestational stage, US Food and Drug Administration classification and guidelines, and potential benefits and limitations of the various therapeutic modalities. This review focuses on the importance of a multidisciplinary team approach, starting with preconception planning and counseling, determining the treatment options depending on the stage of glaucoma and of pregnancy, and emphasizes the involvement of the patients, their obstetrician, and pediatrician through active discussion regarding the various medical, laser, or surgical modalities currently available or under exploration for use during pregnancy and lactation. The ultimate aim is to achieve an optimal balance between the risks and benefits of any type of intervention, and to customize treatment on an individual basis in order to achieve the best outcomes for both mother and fetus.

Management of Glaucoma in Pregnancy

Management of glaucoma during pregnancy represents a challenge for the physician. Important disease and patients' health decisions begin even before conception and continue throughout pregnancy and breastfeeding. The data on this topic is limited due to ethical and legal constraints and challenges of conducting large, prospective, and randomized clinical trials on this patient population. Our review suggests that individually, intraocular pressure is lower in a pregnant woman when compared with a nonpregnant woman. Importantly, the medical management of glaucoma during pregnancy poses special challenges due to the possibility of adverse effects of medications on the fetus and newborn. Laser trabeculoplasty and traditional filtration surgery, and minimally invasive glaucoma surgery, represent nondrug management options. Thus, managing glaucoma in pregnancy is a delicate balance between treatment to prevent damage to the optic nerve in the mother and avoidance of interventions potentially harmful to the fetus. This literature review of published individual and population-based studies was performed to explore current knowledge and guidelines in the management of glaucoma in pregnancy.

Ophthalmic Timolol and Hospitalization for Symptomatic Bradycardia and Syncope: A Case Series

Topical beta-blockers are commonly used for the management of primary open angle glaucoma (POAG). One of the rare but serious side effects of the topical beta-blockers is bradycardia, defined as a heart rate below 60 beats per minute. In few cases, the heart rate drops to much lower level resulting in syncope or symptomatic bradycardia. Topical beta-blockers are still widely used for POAG even though there are much better medications available. We present a series of four cases of symptomatic bradycardia resulting from the use of timolol eye drops and after discontinuation of the eye drops, heart rate improved to normal range (60-100 beats per minute).

Complete atrioventricular block due to timolol eye drops: a case report and literature review

BACKGROUND

Timolol Maleate is a non-selective beta-adrenergic blocker that is commonly used to treat open-angle glaucoma. Despite its topical administration, ophthalmic timolol enters systemic circulation and produces a systemic beta-adrenergic blockade. We report a case of long-term timolol use that uncovered and worsened an underlying cardiac conduction defect demonstrated as a third degree atrioventricular (AV) block.

CASE PRESENTATION

A 62-year old male with a 13-year history of glaucoma was hospitalized due to shortness of breath, dizziness, and amaurosis. Electrocardiography indicated a heart rate (HR) of 29 bpm with complete atrioventricular (AV) block, and the HR was significantly increased with the treatment of isoprenaline. However, the patient experienced bradycardic episodes (- 20 Δbpm) immediately after self-administration of timolol eye drops. The AV block and bradycardia resolved 48-h after timolol cessation. The man was discharged 1 week later with an asymptomatic first-degree A-V block. However, he presented with a worsened A-V block at his one-year checkup.

CONCLUSION

We conclude that chronic topical timolol administration may aggravate a cardiac conduction defect leading to an AV block that is only temporarily resolved by timolol cessation. Patients taking timolol should be routinely monitored for cardiovascular aberrations and if any detected, immediately discontinue timolol therapy. Individuals experiencing timolol induced cardiovascular side effects should receive long term follow-up even if symptoms resolve, as they may be indicative of an underlying conduction defect.