If current blockers

see also:

• congestive cardiac failure

• If blockers are agents which specifically inhibit the If “funny current” in the sino-atrial node which is responsible for pacemaking
• these agents may also cause transient visual disturbances via interaction with hyperpolarisation-activated currents (Ih) in the retina
• the 1st of these, ivabradine (Coralan), was introduced in Australia in 2013 via Authority PBS as an adjunctive Rx of congestive cardiac failure in patients who meet the following criteria:
  • symptomatic systolic CHF with NYHA class II or III
  • in sinus rhythm
  • documented LVEF ⇐ 35%
  • resting heart rate >= 77 bpm prior to Rx starting
  • receiving concomitant optimal standard CHF Rx (eg. ACE inhibitors) which must also include max. tolerated dose of beta adrenergic blockers unless C/I

• sick sinus syndrome
• AV block
• SA block
• acute coronary syndromes
• severe hypotension and bradycardia
• cardiogenic shock
• pregnancy
• lactation
• children
• age > 75yrs - limited data!
• retinitis pigmentosa
• unexpected deterioration of vision whilst on Rx
• prolonged QTc or medications known to cause this
• severe hepatic impairment
• reduce dose or cease if HR < 50 bpm persistently or adverse effects such as dizziness occur.

• metabolised by CYP3A4
• no dose adjustment needed for creatinine clearance > 15mL/min or for mild hepatic impairment

• start at 5mg bd with meals
• after 2wks adjust according to persistent HR:
  • >60bpm: increase to 7.5mg bd
  • 60-60bpm: maintain at 5mg bd
  • <50bpm or symptoms of bradycardia: decrease to 2.5mg bd
• NB. age > 75yrs: use half the above doses