Isoptin Side Effects
Generic name: verapamil
Medically reviewed by Drugs.com. Last updated on Oct 3, 2020.
Note: This document contains side effect information about verapamil. Some of the dosage forms listed on this page may not apply to the brand name Isoptin.
For the Consumer
Applies to verapamil: oral capsule extended release, oral tablet, oral tablet extended release
Other dosage forms:
Side effects requiring immediate medical attention
Along with its needed effects, verapamil (the active ingredient contained in Isoptin) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur while taking verapamil:
- Blue lips and fingernails
- blurred vision
- burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
- chest pain
- coughing that sometimes produces a pink frothy sputum
- difficult, fast, noisy breathing, sometimes with wheezing
- dizziness, faintness, or lightheadedness when getting up from a lying or sitting position suddenly
- increased sweating
- lightheadedness, dizziness, or fainting
- pale skin
- shortness of breath
- slow or irregular heartbeat
- sore throat
- swelling in legs and ankles
- unusual tiredness or weakness
- cold sweats
- feeling of warmth
- redness of the face, neck, arms and occasionally, upper chest
Side effects not requiring immediate medical attention
Some side effects of verapamil may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.
Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- Difficulty having a bowel movement (stool)
- Acid or sour stomach
- difficulty in moving
- joint pain
- muscle aching or cramping
- muscle pains or stiffness
- stomach discomfort, upset, or pain
- trouble sleeping
- unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
- swollen joints
For Healthcare Professionals
Applies to verapamil: compounding powder, intravenous solution, oral capsule extended release, oral tablet, oral tablet extended release
Seizures occurred rarely with IV administration.
Very common (10% or more): Headache (up to 12.1%)
Common (1% to 10%): Dizziness, lethargy
Rare (0.01% to 0.1%): Seizures
Frequency not reported: Rotary nystagmus, sleepiness, vertigo, lightheadedness, tingling, numbness, neuropathy
Common (1% to 10%): Symptomatic hypotension/hypotension/abrupt blood pressure fall, sinus bradycardia/bradycardia (heart rate less than 50 beats/minute), severe tachycardia, ankle edema/edema, development/aggravation of congestive heart failure (CHF), atrioventricular (AV) block, peripheral edema
Uncommon (0.1% to 1%): Second-/third-degree AV block, palpitations, orthostasis
Postmarketing reports: Angina pectoris/chest pain, AV dissociation, ECG abnormal, claudication, hypertension, myocardial infarction, sinus arrest with asystole, decreased myocardial contractility, cardiogenic shock, bradyarrhythmia in atrial fibrillation, vasculitis, erythromelalgia[Ref]
Cardiovascular side effects may occur with greater intensity at higher doses or in patients with a history of myocardial damage.
Approximately 15% of patients who had atrial flutter/fibrillation and received this drug and digoxin developed resting ventricular rates below 50 beats/min; in the same trial, asymptomatic hypotension occurred in approximately 5% of patients.
Asystole occurred after second/third degree AV block and was usually short in duration, with spontaneous cardiac action returning within seconds in the form of a sinus rhythm.[Ref]
Uncommon (0.1% to 1%): Abdominal discomfort/pain
Non-obstructive paralytic ileus was reversible when treatment was stopped.
Gingival hyperplasia occurred when this drug was given over a prolonged period of time, and was reversible once the drug was discontinued.[Ref]
Rare (0.01% to 0.1%): Broncho/laryngeal spasm[Ref]
Bronchospasm and laryngeal spasm occurred during hypersensitivity reactions.[Ref]
Common (1% to 10%): Fatigue, tiredness/malaise, accidental injury, pain
Frequency not reported: Infection, flu syndrome
Common (1% to 10%): Scalp irritation, rash
Uncommon (0.1% to 1%): Itching, urticaria, flushing, exanthema
Frequency not reported: Diaphoresis, photodermatitis
Postmarketing reports: Ecchymosis, bruising, alopecia/hair loss, hyperkeratosis, macules, Stevens-Johnson syndrome, hyperhidrosis/sweating, erythema multiforme, Quincke's edema/angioneurotic edema[Ref]
Itch and urticaria occurred in hypersensitivity reactions.[Ref]
Common (1% to 10%): Sleep disturbance
Uncommon (0.1% to 1%): Bad dreams, depression/emotional depression
Common (1% to 10%): Myalgia
Frequency not reported: Muscle fatigue
Postmarketing reports: Muscle cramps, arthralgia[Ref]
Reversible elevations liver enzymes occurred during treatment, and are likely the result of a hypersensitivity reaction (e.g., allergic hepatitis).[Ref]
Rare (0.01% to 0.1%): Hypersensitivity/allergic reactions
Postmarketing reports: Allergy aggravated[Ref]
Frequency not reported: Lowered glucose tolerance
Postmarketing reports: Renal failure[Ref]
Postmarketing reports: Gynecomastia[Ref]
Gynecomastia occurred in older male patients on prolonged treatment, and was reversible upon discontinuation of this drug.[Ref]
Postmarketing reports: Purpura[Ref]
Postmarketing reports: Blurred vision[Ref]
1. "Product Information. Verelan PM (verapamil)." Schwarz Pharma, Mequon, WI.
2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
3. Cerner Multum, Inc. "Australian Product Information." O 0
4. "Product Information. Covera-HS (verapamil)." Searle, Skokie, IL.
5. "Product Information. Calan (verapamil)." Searle, Skokie, IL.
6. "Product Information. Isoptin (verapamil)." Knoll Pharmaceutical Company, Whippany, NJ.
More about Isoptin (verapamil)
- During Pregnancy or Breastfeeding
- Dosage Information
- Drug Images
- Drug Interactions
- 1 Review
- Drug class: calcium channel blocking agents
Related treatment guides
Some side effects may not be reported. You may report them to the FDA.