Tonocard Side Effects

Generic Name: tocainide

Note: This page contains side effects data for the generic drug tocainide. It is possible that some of the dosage forms included below may not apply to the brand name Tonocard.

It is possible that some side effects of Tonocard may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

For the Consumer

Applies to tocainide: oral tablet

As well as its needed effects, tocainide (the active ingredient contained in Tonocard) may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking tocainide, check with your doctor or nurse as soon as possible:

Less common
  • Trembling or shaking
  • Blisters on skin
  • cough or shortness of breath
  • fever or chills
  • irregular heartbeats
  • peeling or scaling of skin
  • skin rash (severe)
  • sores in mouth
  • unusual bleeding or bruising

Some tocainide side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common
  • Dizziness or lightheadedness
  • loss of appetite
  • nausea
Less common
  • Blurred vision
  • confusion
  • headache
  • nervousness
  • numbness or tingling of fingers and toes
  • skin rash
  • sweating
  • vomiting

For Healthcare Professionals

Applies to tocainide: oral tablet


Tocainide is generally well tolerated. Minor, transient, dose-dependent side effects have occurred frequently (up to 80%) and usually involved nervous system or gastrointestinal symptoms. Approximately 21% of patients discontinued tocainide (the active ingredient contained in Tonocard) because of adverse effects. The incidence of side effects increased when plasma tocainide concentrations exceeded 10 mcg/mL. Tremor may indicate that the maximum dosage is being approached.

General adverse reactions affecting the body as a whole included fatigue (0.8% to 1.6%) and hot or cold sensations (0.5% to 1.5%). Cinchonism, asthenia, and malaise have been reported in less than 1% of patients.


Gastrointestinal side effects are the most frequently observed. Nausea, vomiting, and anorexia have occurred in 15% to 35% of patients. Dosage reductions or administration with food, which will not affect tocainide (the active ingredient contained in Tonocard) plasma concentrations, helps minimize these side effects. Diarrhea has been reported in 6.8% of patients. Pancreatitis, abdominal discomfort, constipation, dysphagia, stomatitis, taste alteration, dry mouth and thirst were reported in less than 1% of patients.

Nervous system

Nervous system side effects have occurred in 15% to 25% of patients on chronic therapy. Lightheadedness/dizziness/vertigo (8% to 25.3%), tremors (2.9% to 21.6%), paresthesia (3.5% to 9.2%), coordination difficulties (1.2%), and headache (2.1% to 4.6%) have been reported. Neurologic side effects are usually dose-related and resolve with dosage reductions. Adverse effects such as coma, seizures, myasthenia gravis, dysarthria, decreased mental acuity/impaired memory, increased stuttering/slurred speech, and local anesthesia have been reported in less than 1% of patients.

Tocainide, like lidocaine, crosses the blood-brain barrier and may produce neurotoxicity, including seizures. Tremor and paresthesias indicate a maximum tolerable dosage.


Cardiovascular side effects such as exacerbation of old or induction of new arrhythmias, including ventricular tachycardia or fibrillation, have occurred in 16% of patients. Although tocainide (the active ingredient contained in Tonocard) has a minimal effect on the sinus node, cases of sinus arrest and SA block have been reported, particularly in patients with sick sinus syndrome. Exacerbation of congestive heart failure occurred in 1% to 5% of patients. Bradycardia (1.8%), hypotension (3.4%), and chest pain (1.6%) have been reported. Angina, hypertension, claudication, increased QRS duration, extension of acute myocardial infarction, vaso-vagal episodes, syncope, and edema have occurred.


Tocainide-associated blood dyscrasias have been reported most often during the first 2 to 12 weeks of therapy.

Hematologic side effects of tocainide have been rare (0.2% of patients), but serious reactions and death have occurred. Aplastic anemia and agranulocytosis have been associated with tocainide, some were irreversible and resulted in death. Weekly complete blood count analysis is recommended during the first three months of therapy and monthly, thereafter. Bone marrow depression and granuloma, hemolytic anemia, anemia, leukopenia, neutropenia, thrombocytopenia, and eosinophilia have been associated with tocainide therapy in less in 1% of patients. Septicemia and septic shock have been reported.


Hypersensitivity reactions manifesting as rash, fever, joint pain, eosinophilia, or abnormal liver function tests have been reported in up to 25% of patients. Stevens-Johnson syndrome has been associated with tocainide (the active ingredient contained in Tonocard) Interstitial pneumonitis is a rare side effect of tocainide and may be initiated by a hypersensitivity mechanism.


Data from 21 reports of severe skin reactions between 1985 to 1986, indicated 67% of the reactions occurred during the first 3 weeks of therapy.

Dermatologic side effects occurred in 12% to 28% of patients. Serious reactions have included Stevens-Johnson syndrome, erythema multiforme, rash with stomatitis, or rash requiring or prolonging hospitalization. Overall, the incidence of serious skin reactions is 0.5 to 3.8 per 100,000 prescriptions of tocainide, with fatalities in 0.9 per 100,000 prescriptions. Diaphoresis has been reported in up to 8.3% of patients.


Psychiatric side effects have included confusion/disorientation/hallucinations (2.1% to 11.2%), altered mood/awareness (1.5% to 11%), nervousness (11.5%), and anxiety (1.1% to 1.5%). Psychosis/disturbances, depression, agitation, insomnia/sleep disturbances, and dream abnormalities have been reported in less than 1% of patients.


Respiratory side effects, although rare, have resulted in death. Tocainide-associated pulmonary fibrosis has occurred, most often in seriously ill patients. Symptoms of dyspnea and cough usually presented within 3 to 18 weeks of initiation of therapy. Interstitial infiltrates were seen on radiologic examination. Respiratory arrest, pulmonary edema, fibrosing alveolitis, pneumonia, interstitial pneumonitis (0.03%), dyspnea, hiccough, yawning, and smell alterations have been reported in less than 1% of patients.

Evidence of a hypersensitivity mechanism has been reported for tocainide-associated pulmonary fibrosis.


Hepatic side effects usually have been mild and transient, manifesting as slightly elevated liver function tests. Hepatitis and jaundice have been reported in less than 1% of patients.


A 75-year-old man with a history of coronary artery bypass grafting and short runs of ventricular tachycardia was given tocainide (the active ingredient contained in Tonocard) 400 mg every 8 hours. Three weeks after initiation of therapy he developed unexplained malaise, chills, sweats, and fever and was given oral antibiotics. His physical exam was noncontributory; laboratory tests revealed a white blood cell count of 4,400/mm3. An evaluation of typical and atypical infectious pathogens was negative. A CT scan noted a right pleural effusion and hepatosplenomegaly. Bone marrow aspiration revealed numerous noncaseating granuloma, decreased iron stores, and 30% cellularity. A serum ANA was positive at 1:640 (speckled pattern). Resolution of all symptoms occurred within one week of discontinuing tocainide. Rechallenge was not attempted.

Immunologic and clinical changes consistent with a lupus-like syndrome have been reported.


Musculoskeletal side effects such as arthritis/arthralgia (4.7%) and myalgia (1.7%), and ataxia (02.% to 10.8%) have been reported. Side effects occurring in less than 1% of patients included muscle cramps/twitches/spasms, neck pain or pain radiating from the neck, and shoulder pressure.


Ocular disturbances have included blurred vision in up to 10% of patients. Nystagmus occurred less frequently (1.1%).


Ototoxicity characterized by vertigo and tinnitus/hearing loss has occurred in 25.3% and 1.1% of patients, respectively. Rare incidences of earache have been reported.


Genitourinary side effects including urinary retention, polyuria, and increased diuresis have occurred in less than 1% of patients.

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