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Verapamil (Verapamil Hydrochloride) - Side Effects and Adverse Reactions



Serious adverse reactions are uncommon when verapamil hydrochloride therapy is initiated with upward dose titration within the recommended single and total daily dose. See WARNINGS for discussion of heart failure, hypotension, elevated liver enzymes, AV block, and rapid ventricular response. Reversible (upon discontinuation of verapamil) non-obstructive, paralytic ileus has been infrequently reported in association with the use of verapamil. The following reactions to orally administered verapamil occurred at rates greater than 1% or occurred at lower rates but appeared clearly drug-related in clinical trials in 4,954 patients:

 Constipation  7.3%  Dyspnea  1.4%
 Dizziness  3.3%  Bradycardia  
 Nausea  2.7%  (HRgretwe then 50/min)  1.4%
 Hypotension  2.5%  AV block  
 Headache  2.2%       total (1°, 2°, 3°)  1.2%
 Edema  1.9%       2° and 3°  0.8%
 CHF,Pulmonary edema  1.8%  Rash  1.2%
 Fatigue  1.7%  Flushing  0.6%
 Elevated liver enzymes(see WARNINGS)      

In clinical trials related to the control of ventricular response in digitalized patients who had atrial fibrillation or flutter, ventricular rates below 50 at rest occurred in 15% of patients and asymptomatic hypotension occurred in 5% of patients.

The following reactions, reported in 1% or less of patients, occurred under conditions (open trials, marketing experience) where a causal relationship is uncertain; they are listed to alert the physician to a possible relationship:

Cardiovascular: angina pectoris, atrioventricular dissociation, chest pain, claudication, myocardial infarction, palpitations, purpura (vasculitis), syncope.

Digestive system:  diarrhea, dry mouth, gastrointestinal distress, gingival hyperplasia.

Hemic and lymphatic:  ecchymosis or bruising.

Nervous system:  cerebrovascular accident, confusion, equilibrium disorders, insomnia, muscle cramps, paresthesia, psychotic symptoms, shakiness, somnolence.

Skin:  arthralgia and rash, exanthema, hair loss, hyperkeratosis, maculae, sweating, urticaria, Stevens-Johnson syndrome, erythema multiforme.

Special senses: blurred vision, tinnitus.

Urogenital: gynecomastia, galactorrhea/hyperprolactinemia, increased urination, spotty menstruation, impotence.

Treatment of acute cardiovascular adverse reactions

The frequency of cardiovascular adverse reactions that require therapy is rare; hence, experience with their treatment is limited. Whenever severe hypotension or complete AV block occurs following oral administration of verapamil, the appropriate emergency measures should be applied immediately; e.g., intravenously administered norepinephrine bitartrate, atropine sulfate, isoproterenol hydrochloride (all in the usual doses), or calcium gluconate (10% injection). In patients with hypertrophic cardiomyopathy (IHSS), alpha-adrenergic agents (phenylephrine hydrochloride, metaraminol bitartrate, or methoxamine hydrochloride) should be used to maintain blood pressure, and isoproterenol and norepinephrine should be avoided. If further support is necessary, dopamine hydrochloride or dobutamine hydrochloride may be administered. Actual treatment and dosage should depend on the severity of the clinical situation and the judgment and experience of the treating physician.


Below is a sample of reports where side effects / adverse reactions may be related to Verapamil. The information is not vetted and should not be considered as verified clinical evidence.

Possible Verapamil side effects / adverse reactions in 49 year old female

Reported by a individual with unspecified qualification from United States on 2011-10-11

Patient: 49 year old female weighing 59.0 kg (129.8 pounds)

Reactions: Nausea, Cardiac Enzymes Increased, Prinzmetal Angina, Drug Interaction, Somnolence, Heart Rate Decreased, Chest Pain, Mitral Valve Incompetence, Blood Pressure Decreased, Vasospasm

Adverse event resulted in: hospitalization

Suspect drug(s):

Other drugs received by patient possibly interacting with the suspect drug:
    Dosage: 180 mg, unk
    Administration route: Oral

Dihydroergotamine Mesylate
    Dosage: 1 mg, unk

    Dosage: 7 mg, unk
    Indication: Smoking Cessation Therapy

Other drugs received by patient: Amantadine HCL; Acetaminophen and Hydrocodone Bitartrate; Gabapentin; Duloxetime Hydrochloride; Morphine Sulfate; Lorazepam; Natalizumab; Haloperidol; Fentanyl

Possible Verapamil side effects / adverse reactions in 88 year old male

Reported by a consumer/non-health professional from United States on 2011-10-13

Patient: 88 year old male

Reactions: Abnormal Behaviour, Gait Disturbance, Cerebrovascular Accident, Fall

Suspect drug(s):





    Dosage: as needed.



Possible Verapamil side effects / adverse reactions in 58 year old female

Reported by a health professional (non-physician/pharmacist) from United States on 2011-10-18

Patient: 58 year old female

Reactions: Toxicity TO Various Agents, Blood Pressure Decreased, Cardiogenic Shock, Blood Glucose Abnormal, Hypokalaemia

Adverse event resulted in: hospitalization

Suspect drug(s):

See index of all Verapamil side effect reports >>

Drug label data at the top of this Page last updated: 2010-11-22

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