Authors

  1. Bartholomew, Rachel N. PharmD
  2. Sheridan, Daniel J. MS, RPh

Article Content

My patient with heart failure has been prescribed ivabradine. The labeling lists "luminous phenomena" as a commonly reported adverse reaction. What should I teach my patient about these?-T.W., UTAH

 

Rachel N. Bartholomew, PharmD, and Daniel J. Sheridan, MS, RPh, respond: Some patients using ivabradine, a hyperpolarization-activated cyclic nucleotide-gated channel blocker indicated to treat heart failure, may complain of vision disturbances such as bright spots that don't go away in certain parts of their field of vision. They may describe them as bright halos or colored bright lights that interfere with their ability to see clearly. Patients may also more simply explain that they're "seeing stars" or having "fuzzy" vision changes.

 

These adverse reactions to ivabradine are called luminous phenomena or phosphenes. According to ivabradine's package insert, luminous phenomena are typically described as a transiently enhanced brightness in a limited area of the visual field, halos, image decomposition (stroboscopic or kaleidoscopic effects), colored bright lights, or multiple images (retinal persistency).1 For patients who experience luminous phenomena, symptoms generally appear within 2 months after therapy begins.1

 

Ivabradine's novel mechanism of action reduces the spontaneous pacemaker activity of the sinoatrial node by selectively inhibiting the If-current (If). The letter "f" in If originates with the word "funny" because of its unusual properties compared with other known pathways.2 This results in a reduced heart rate without affecting ventricular repolarization or myocardial contractility. Cardiac If is similar to a retinal current, hyperpolarization-activated current (Ih), which is involved in decreasing retinal responses to bright light stimuli. Ivabradine also partially inhibits Ih.3,4 This mechanism is thought to be responsible for luminous phenomena.

 

Fortunately, luminous phenomena aren't very common. In one hallmark clinical trial, luminous phenomena were reported in 2.8% of patients using ivabradine.5 Luminous phenomena were generally reported to be of mild to moderate intensity and led to treatment discontinuation in less than 1% of patients; most resolved during or after treatment.

 

Patients who are initiating ivabradine therapy should be taught about the potential for luminous phenomena. Advise your patient that visual disturbances may continue repeatedly throughout the duration of ivabradine use, but that symptoms usually resolve when the medication is discontinued. Advise patients that visual disturbances may also subside spontaneously during continued treatment. Because sudden changes of light intensity may occur spontaneously, warn your patient to use caution while driving, especially at night.1

 

REFERENCES

 

1. Corlanor (ivabradine) [prescribing information]. Thousand Oaks, CA: Amgen; 2017. http://pi.amgen.com/~/media/amgen/repositorysites/pi-amgen-com/corlanor/corlanor_pi.ashx. [Context Link]

 

2. Sulfi S, Timmis AD. Ivabradine-the first selective sinus node I(f) channel inhibitor in the treatment of stable angina. Int J Clin Pract. 2006;60(2):222-228. [Context Link]

 

3. Nawarskas JJ, Bowman BN, Anderson JR. Ivabradine: a unique and intriguing medication for treating cardiovascular disease. Cardiol Rev. 2015;23(4):201-211. [Context Link]

 

4. Melgari D, Brack KE, Zhang C, et al hERG potassium channel blockade by the HCN channel inhibitor bradycardic agent ivabradine. J Am Heart Assoc. 2015;4(4):e001813. [Context Link]

 

5. Swedberg K, Komajda M, Bohm M, Borer JS, Ford I, Tavazzi L. Rationale and design of a randomized, double-blind, placebo-controlled outcome trial of ivabradine in chronic heart failure: the Systolic Heart Failure Treatment with the I(f) Inhibitor Ivabradine Trial (SHIFT). Eur J Heart Fail. 2010;12(1):75-81. [Context Link]