Calan (Verapamil)
Medication information written by Dr. Larisa Roybal, PharmD
Updated - January 25, 2021
Calan (Verapamil) Medication Information
Uses
Calan is a calcium ion influx inhibitor used for angina, arrhythmias, and essential hypertension.
Dosage
There are oral tablets available in several different strengths:
- 40 mg
- 80 mg
- 120 mg
Side Effects
The most common side effects of Calan include:
- Constipation
- Dizziness
- Nausea
- Hypotension
- Headache
- Edema
- CHF
- Pulmonary edema
- Fatigue
- Elevated liver enzymes
Speak with your doctor or pharmacist for a full list of side effects that applies to you.
Precautions
Since verapamil is highly metabolized by the liver, it should be administered cautiously to patients with impaired hepatic function. Severe liver dysfunction prolongs the elimination half-life of verapamil to about 14 to 16 hours.
It has been reported that verapamil decreases neuromuscular transmission in patients with Duchenne's muscular dystrophy, and that verapamil prolongs recovery from the neuromuscular blocking agent vecuronium. It may be necessary to decrease the dosage of verapamil when it is administered to patients with attenuated neuromuscular transmission.
About 70% of an administered dose of verapamil is excreted as metabolites in the urine. Verapamil is not removed by hemodialysis. Until further data are available, verapamil should be administered cautiously to patients with impaired renal function.
Interactions
Some of the common drug interactions with Calan:
- Alcohol
- Beta-blocker
- Digoxin
- Disopyramide
- Flecainide
- Quinidine
- Lithium
- Rifampin
- Phenobarbital
Speak with your doctor or pharmacist for more information.
Storage
Store at controlled room temperature (59-77ºF). Protect from light.
Pharmacist Tips
- Since the half-life of verapamil increases during chronic dosing, maximum response may be delayed.
- Upward titration should be based on therapeutic efficacy and safety evaluated approximately eight hours after dosing.
- Safety and effectiveness in pediatric patients have not been established.
Verapamil FAQs
Can I take this with food?
Calan can be taken with or without food.
Can I take this if I am pregnant?
There are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Verapamil crosses the placental barrier and can be detected in umbilical vein blood at delivery.
Can I take this while breastfeeding?
Verapamil is excreted in human milk. Because of the potential for adverse reactions in nursing infants from verapamil, nursing should be discontinued while verapamil is administered.
Can this medication be titrated?
Dose should be individualized by titration.
How long does it take to see hypertensive benefit of Calan?
The antihypertensive effects of Calan are evident within the first week of therapy. Upward titration should be based on therapeutic efficacy, assessed at the end of the dosing interval.
What is the maximal daily dose of Calan?
The usefulness and safety of doses exceeding 480 mg/day have not been established; therefore, this daily dosage should not be exceeded.
Related Drugs
Reference:
Calan {package insert}. New York, NY: Pfizer; 2009.
https://www.accessdata.fda.gov/drugsatfda_docs/label/2009/018817s021lbl.pdf
Author: Dr. Larisa Roybal, PharmD
Dr. Roybal is a board-certified pharmacotherapy specialist who has practiced in both ambulatory and acute care settings. Her pharmacy interests include oncology and general inpatient pharmacy.
The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.
