August 30, 2016
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Side Effects


TARKA has been evaluated in over 1,957 subjects and patients. Of these, 541 patients, including 23% elderly patients, participated in U.S. controlled clinical trials, and 251 were studied in foreign controlled clinical trials. In clinical trials with TARKA, no adverse experiences peculiar to this combination drug have been observed. Adverse experiences that have occurred have been limited to those that have been previously reported with verapamil or trandolapril. TARKA has been evaluated for long-term safety in 272 patients treated for 1 year or more. Adverse experiences were usually mild and transient.

Discontinuation of therapy because of adverse events in U.S. placebo-controlled hypertension studies was required in 2.6% and 1.9% of patients treated with TARKA and placebo, respectively.

Adverse experiences occurring in 1% or more of the 541 patients in placebo-controlled hypertension trials who were treated with a range of trandolapril (0.5-8 mg) and verapamil (120240 mg) combinations are shown below.


(N = 541) % Incidence (% Discontinuance)
(N = 206) % Incidence (% Discontinuance)
AV Block First Degree 3.9 (0.2) 0.5 (0.0)
Bradycardia 1.8 (0.0) 0.0 (0.0)
Bronchitis 1.5 (0.0) 0.5 (0.0)
Chest Pain 2.2 (0.0) 1.0 (0.0)
Constipation 3.3 (0.0) 1.0 (0.0)
Cough 4.6 (0.0) 2.4 (0.0)
Diarrhea 1.5 (0.2) 1.0 (0.0)
Dizziness 3.1 (0.0) 1.9 (0.5)
Dyspnea 1.3 (0.4) 0.0 (0.0)
Edema 1.3 (0.0) 2.4 (0.0)
Fatigue 2.8 (0.4) 2.4 (0.0)
Headache(s)+ 8.9 (0.0) 9.7 (0.5)
Increased Liver Enzymes* 2.8 (0.2) 1.0 (0.0)
Nausea 1.5 (0.2) 0.5 (0.0)
Pain Extremity(ies) 1.1 (0.2) 0.5 (0.0)
Pain Back+ 2.2 (0.0) 2.4 (0.0)
Pain Joint(s) 1.7 (0.0) 1.0 (0.0)
Upper Respiratory Tract Infection(s)+ 5.4 (0.0) 7.8 (0.0)
Upper Respiratory Tract Congestion+ 2.4 (0.0) 3.4 (0.0)
* Also includes increase in SGPT, SGOT, Alkaline Phosphatase
+ Incidence of adverse events is higher in Placebo group than TARKA patients

Other clinical adverse experiences possibly, probably, or definitely related to drug treatment occurring in 0.3% or more of patients treated with trandolapril/verapamil combinations with or without concomitant diuretic in controlled or uncontrolled trials (N = 990) and less frequent, clinically significant events (in italics) include the following:


Angina, AV block second degree, bundle branch block, edema, flushing, hypotension, myocardial infarction , palpitations, premature ventricular contractions, nonspecific ST-T changes, near syncope, tachycardia.

Central Nervous System

Drowsiness, hypesthesia, insomnia, loss of balance, paresthesia, vertigo.


Pruritus, rash.

Emotional, Mental, Sexual States

Anxiety, impotence, abnormal mentation.

Eye, Ear, Nose, Throat

Epistaxis, tinnitus, upper respiratory tract infection, blurred vision.


Diarrhea, dyspepsia, dry mouth, nausea.

General Body Function

Chest pain, malaise, weakness.


Endometriosis, hematuria, nocturia, polyuria, proteinuria.


Decreased leukocytes, decreased neutrophils.

Musculoskeletal System

Arthralgias/myalgias, gout (increased uric acid).




Angioedema has been reported in 3 (0.15%) patients receiving TARKA in U.S. and foreign studies (N = 1,957). Angioedema associated with laryngeal edema may be fatal. If angioedema of the face, extremities, lips, tongue, glottis, and/or larynx occurs, treatment with TARKA should be discontinued and appropriate therapy instituted immediately (see WARNINGS).


(See WARNINGS). In hypertensive patients, hypotension occurred in 0.6% and near syncope occurred in 0.1%. Hypotension or syncope was a cause for discontinuation of therapy in 0.4% of hypertensive patients.

Treatment Of Acute Cardiovascular Adverse Reactions

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


Other adverse experiences (in addition to those in table and listed above) that have been reported with the individual components are listed below.

Verapamil Component


(See WARNINGS). CHF/pulmonary edema, AV block 3°, atrioventricular dissociation, claudication, purpura (vasculitis), syncope.

Digestive System

Gingival hyperplasia. Reversible, (upon discontinuation of verapamil) nonobstructive, paralytic ileus has been infrequently reported in association with the use of verapamil.

Hemic and Lymphatic

Ecchymosis or bruising.

Nervous System

Cerebrovascular accident, confusion, psychotic symptoms, shakiness, somnolence.


Exanthema, hair loss, hyperkeratosis, maculae, sweating, urticaria, Stevens-Johnson syndrome, erythema multiform.


Gynecomastia, galactorrhea/hyperprolactinemia, increased urination, spotty menstruation.

Trandolapril Component

Emotional, Mental, Sexual States

Decreased libido.



Clinical Laboratory Test Findings


(See WARNINGS). Low white blood cells, low neutrophils, low lymphocytes, low platelets.

Serum Electrolytes

Hyperkalemia (see PRECAUTIONS), hyponatremia.

Renal Function Tests

Increases in creatinine and blood urea nitrogen levels occurred in 1.1 percent and 0.3 percent, respectively, of patients receiving TARKA with or without hydrochlorothiazide therapy. None of these increases required discontinuation of treatment. Increases in these laboratory values are more likely to occur in patients with renal insufficiency or those pretreated with a diuretic and, based on experience with other ACE inhibitors, would be expected to be especially likely in patients with renal artery stenosis (see PRECAUTIONS and WARNINGS).

Liver Function Tests

Elevations of liver enzymes (SGOT, SGPT, LDH, and alkaline phosphatase) and/or serum bilirubin occurred. Discontinuation for elevated liver enzymes occurred in 0.9 percent of patients (see WARNINGS).

Post Marketing Experience

There has been a single postmarketing report of paralysis (tetraparesis) associated with the combined use of verapamil and colchicine. This may have been caused by colchicine crossing the blood-brain barrier due to CYP3A4 and P-gp inhibition by verapamil. Combined use of verapamil and colchicine is not recommended (see DRUG INTERACTIONS).

Read the Tarka (trandolapril and verapamil er) Side Effects Center for a complete guide to possible side effects


In vitro metabolic studies indicate that verapamil is metabolized by cytochrome P450 including CYP3A4, CYP1A2, CYP2C8, CYP2C9 and CYP2C18. Verapamil has been shown to be an inhibitor of CYP3A4 enzymes and P-glycoprotein (P-gp).

Clinically significant interactions have been reported with inhibitors of CYP3A4 (e.g. erythromycin, ritonavir) causing elevation of plasma levels of verapamil while inducers of CYP3A4 (e.g. rifampin) have caused a lowering of plasma levels of verapamil. Therefore, patients receiving inhibitors or inducers of the cytochrome P450 system should be monitored for drug interactions.


Concurrent use of verapamil increases exposure to ivabradine and may exacerbate bradycardia and conduction disturbances. Avoid co-administration of verapamil and ivabradine.


Clinical use of verapamil in digitalized patients has shown the combination to be well tolerated if digoxin doses are properly adjusted. Chronic verapamil treatment can increase serum digoxin levels by 50 to 75% during the first week of therapy, and this can result in digoxin toxicity. In patients with hepatic cirrhosis, the influence of verapamil on digoxin kinetics is magnified. Verapamil may reduce total body clearance and extrarenal clearance of digitoxin by 27% and 29%, respectively. Maintenance digoxin doses should be reduced when verapamil is administered, and the patient should be carefully monitored to avoid over-or under-digitalization. Whenever overdigitalization is suspected, the daily dose of digoxin should be reduced or temporarily discontinued. Upon discontinuation of any verapamil-containing regime including TARKA (trandolapril/verapamil hydrochloride ER), the patient should be reassessed to avoid underdigitalization. No clinically significant pharmacokinetic interaction has been found between trandolapril (or its metabolites) and digoxin.


Verapamil Component

Increased sensitivity to the effects of lithium (neurotoxicity) has been reported during concomitant verapamil-lithium therapy with either no change or an increase in serum lithium levels. Increased serum lithium levels and symptoms of lithium toxicity have been reported in patients receiving concomitant lithium and ACE inhibitor therapy. TARKA and lithium should be coadministered with caution, and frequent monitoring of serum lithium levels is recommended. If a diuretic is also used, the risk of lithium toxicity may be increased.


Hypotension, bradyarrhythmias, and lactic acidosis have been observed in patients receiving concurrent clarithromycin.


Hypotension, bradyarrhythmias, and lactic acidosis have been observed in patients receiving concurrent erythromycin ethylsuccinate.


The interaction between cimetidine and chronically administered verapamil has not been studied. Variable results on clearance have been obtained in acute studies of healthy volunteers; clearance of verapamil was either reduced or unchanged. No clinically significant pharmacokinetic interaction has been found between trandolapril (or its metabolites) and cimetidine.

Antiarrhythmic Agents

Verapamil Component

Disopyramide Phosphate

Data on possible interactions between verapamil and disopyramide phosphate are not available. Therefore, disopyramide should not be administered within 48 hours before or 24 hours after verapamil administration.


A study of healthy volunteers showed that the concomitant administration of flecainide and verapamil may have additive effects on myocardial contractility, AV conduction, and repolarization. Concomitant therapy with flecainide and verapamil may result in additive negative inotropic effect and prolongation of atrioventricular conduction.


In a small number of patients with hypertrophic cardiomyopathy (IHSS), concomitant use of verapamil and quinidine resulted in significant hypotension. Until further data are obtained, combined therapy of verapamil and quinidine in patients with hypertrophic cardiomyopathy should probably be avoided.

The electrophysiological effects of quinidine and verapamil on AV conduction were studied in 8 patients. Verapamil significantly counteracted the effects of quinidine on AV conduction. There has been a report of increased quinidine levels during verapamil therapy.

Antihypertensive Agents

Concomitant use of TARKA with other antihypertensive agents including diuretics, vasodilators, beta-adrenergic blockers, and alpha-antagonists may result in additive hypotensive effects. There are reports that verapamil may result in higher concentrations of the alpha-agonists prazosin and terazosin.

Dual Blockade of the Renin-Angiotensin System (RAS)

Trandolapril Component

Dual blockade of the RAS with angiotensin receptor blockers, ACE inhibitors, or aliskiren is associated with increased risks of hypotension, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy. Most patients receiving the combination of two RAS inhibitors do not obtain any additional benefit compared to monotherapy. In general, avoid combined use of RAS inhibitors. Closely monitor blood pressure, renal function and electrolytes in patients on TARKA and other agents that affect the RAS.

Do not co-administer aliskiren with TARKA in patients with diabetes. Avoid use of aliskiren with TARKA in patients with renal impairment (GFR < 60 ml/min).

Beta Blockers

Verapamil Component

Concomitant therapy with beta-adrenergic blockers and verapamil may result in additive negative effects on heart rate, atrioventricular conduction, and/or cardiac contractility. Drug interaction studies have indicated that the maximum concentrations of metoprolol and propanolol are increased after the administration of verapamil. The use of verapamil in combination with a beta-adrenergic blocker should be used only with caution, and close monitoring.

Asymptomatic bradycardia (36 beats/min) with a wandering atrial pacemaker has been observed in a patient receiving concomitant timolol (a beta-adrenergic blocker) eyedrops and oral verapamil.

Concomitant Diuretic Therapy

Trandolapril Component

As with other ACE inhibitors, patients on diuretics, especially those on recently instituted diuretic therapy, may occasionally experience an excessive reduction of blood pressure after initiation of therapy with TARKA. The possibility of exacerbation of hypotensive effects with TARKA may be minimized by either discontinuing the diuretic or cautiously increasing salt intake prior to initiation of treatment with TARKA. If it is not possible to discontinue the diuretic, the starting dose of TARKA should be reduced (see DOSAGE AND ADMINISTRATION). No clinically significant pharmacokinetic interaction has been found between trandolapril (or its metabolites) and furosemide.

Agents Increasing Serum Potassium

Trandolapril Component

Trandolapril can attenuate potassium loss caused by thiazide diuretics and increase serum potassium when used alone. Use of potassium-sparing diuretics (spironolactone, triamterene, or amiloride), potassium supplements, or potassium-containing salt substitutes concomitantly with ACE inhibitors can increase the risk of hyperkalemia. If concomitant use of such agents is indicated, they should be used with caution and with appropriate monitoring of serum potassium (see PRECAUTIONS).

HMG-CoA Reductase Inhibitors (“Statins”)

Verapamil Component

The use of HMG-CoA reductase inhibitors that are CYP3A4 substrates in combination with verapamil has been associated with reports of myopathy/rhabdomyolysis.

Co-administration of multiple doses of 10 mg of verapamil with 80 mg simvastatin resulted in exposure to simvastatin 2.5-fold that following simvastatin alone. Limit the dose of simvastatin in patients on verapamil to 10 mg daily. Limit the daily dose of lovastatin to 40 mg. Lower starting and maintenance doses of other CYP3A4 substrates (e.g., atorvastatin) may be required as verapamil may increase the plasma concentration of these drugs.

Non-Steroidal Anti-Inflammatory Agents including Selective Cyclooxygenase-2 Inhibitors (COX-2 Inhibitors)

Trandolapril component

In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, co-administration of NSAIDs, including selective COX-2 inhibitors, with ACE inhibitors, including trandolapril, may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving trandolapril and NSAID therapy.

The antihypertensive effect of ACE inhibitors, including trandolapril may be attenuated by NSAIDs.

Other (Verapamil Component)


Verapamil has been given concomitantly with short-and long-acting nitrates without any undesirable drug interactions. The pharmacologic profile of both drugs and the clinical experience suggest beneficial interactions.


Verapamil may increase carbamazepine concentrations during combined therapy. This may produce carbamazepine side effects such as diplopia, headache, ataxia, or dizziness.

Anti-infective Agents

Therapy with rifampin may markedly reduce oral verapamil bioavailability. There have been reports that erythromycin and telithromycin may increase concentrations of verapamil.


Phenobarbital therapy may increase verapamil clearance.

Immunosuppressive Agents

Verapamil therapy may increase serum levels of cyclosporin, sirolimus and tacrolimus.


Verapamil therapy may inhibit the clearance and increase the plasma levels of theophylline.

Tranquilizers/ Anti-depressants

Due to metabolism via the CYP enzyme system, there have been reports that verapamil may increase the concentrations of buspirone, midazolam, almotriptan and imipramine.


Colchicine is a substrate for both CYP3A and the efflux transporter, P-gp. Verapamil is known to inhibit CYP3A and P-gp. When verapamil and colchicine are administered together, the potential inhibition of P-gp and/or CYP3A by verapamil may lead to increased exposure to colchicine (see DRUG INTERACTIONS).


Verapamil, a P-gp inhibitor, increases exposure to dabigatran (a thrombin inhibitor) when administered concomitantly; however, no dose adjustment of dabigatran is required when administered with verapamil.


Concentrations of verapamil may be increased by the concomitant administration of protease inhibitors such as ritonavir, and reduced by the concomitant administration of sulfinpyrazone, or St John's Wort.

Concentrations of doxorubicin may be increased by the administration of verapamil.

There have been reports that verapamil may elevate the concentrations of the oral anti-diabetic glyburide.

Inhalation Anesthetics

Animal experiments have shown that inhalation anesthetics depress cardiovascular activity by decreasing the inward movement of calcium ions. When used concomitantly, inhalation anesthetics and calcium antagonists, such as verapamil, should be titrated carefully to avoid excessive cardiovascular depression.

Neuromuscular Blocking Agents

Clinical data and animal studies suggest that verapamil may potentiate the activity of neuromuscular blocking agents (curare-like and depolarizing). It may be necessary to decrease the dose of verapamil and/or the dose of the neuromuscular blocking agent when the drugs are used concomitantly.


Nitritoid reactions (symptoms include facial flushing, nausea, vomiting and hypotension) have been reported rarely in patients on therapy with injectable gold (sodium aurothiomalate) and concomitant ACE inhibitor therapy including TARKA.

Other (Trandolapril Component)

No clinically significant pharmacokinetic interaction has been found between trandolapril (or its metabolites) and nifedipine.

The anticoagulant effect of warfarin was not significantly changed by trandolapril.

Anti-diabetic Agents

The concomitant use of ACE inhibitors such as trandolapril with antidiabetic medications (insulin or oral hypoglycemic agents) may result in increased blood glucose lowering effects.

Read the Tarka Drug Interactions Center for a complete guide to possible interactions

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 7/25/2016

Side Effects

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