Verapamil (Calan, Verelan, Calan SR, Isoptin) Considerations for Use*

US/FDA Approved Indication: Heart Rate Control for Atrial Fibrillation

Click here to view a Print Quality PDF of this table

Black Box Warning*  

Mechanism of Action

Blocks calcium-dependent contractions in cardiac and peripheral smooth muscle leading to vasodilation; slows cardiac conduction through SA node


Acute setting: 0.075 to 0.15 mg/kg (average 5 to 10 mg) IV over 2 minutes; 2nd dose of 10 mg IV may be given 15-30 minutes later if needed

Non-acute setting or maintenance: 120 to 480 mg daily, slow-release/extended release available and preferred

Elderly: In general, use lower adult dosage and administer over at least 3 minutes; adjust dosage based on clinical response

Hepatic Impairment: Use with caution; if possible reduce initial dosage to about 33% of the usual starting dosage and adjust based on clinical goals

Renal Impairment: Use with caution; no dosage adjustment needed

  • severe LV dysfunction
  • hypotension (SBP < 90)
  • cardiogenic shock
  • sick sinus syndrome without pacemaker
  • 2nd or 3rd deg ree AV block without pacemaker
  • A-Fib/flutter conducted via accessory pathway (ie, Wolff -Parkinson-White)
  • Major Side Effects

    hypotension, heart block, HF

    Dosage forms and Strengths

    40 mg, 80 mg, 120 mg immediate - release tablets (Calan®)
    120 mg, 180 mg, 240 mg sustained - release tablets (Isoptin® SR)
    120 mg, 180 mg, 240 mg, 360 mg sustained - release capsules (Verelan®) 100mg, 200 mg, 300 mg extended - release (Verelan® PM)
    180 mg, 240 mg extended - release tablets (Covera - HS®)

    IV: 2.5 mg/mL solution for injection

    Special Notes

    Many verapamil products are not equivalent on a mg:mg basis; monitor response and side effects when interchanging between products.

    Covera-HS and Verelan PM are chronotherapeutic products; give at bedtime to blunt early morning surge in blood pressure


    Take with food or milk to minimize gastric irritation

    Sustained-release tablets may be broken and each piece swallowed whole; do not chew or crush

    Extended-release table ts should be swallowed whole

    Contents of sustained-release capsules may be sprinkled on food (eg, apple sauce); do not chew or crush capsule contents

    Empty tablets that appear in stool are not significant

    * Refer to prescribing information for more complete information.
    †Dosages given in the table may differ from those recommended by the manufacturers.


    1. American College of Cardiology (ACC), American Heart Association (AHA), and the European Society of Cardiology (ESC). ACC/AHA/ESC 2006 Guidelines for the Management of Patients with Atrial Fibrillation. Washington, DC: American College of Cardiology.
    2. Heart Rhythm Society. AF360 Pocket Guide: Practical Rate and Rhythm Management of Atrial Fibrillation. 2010, Washington, DC: Heart Rhythm Society.
    3. Tarascon Pocket Pharmacopoeia® 2012.