"What are angiotensin receptor blockers (ARBs) and how do they work?
The class of drugs called angiotensin receptor blockers (ARBs), as the class name suggests, are drugs that block the action of angiotensin. Specifically, ARBs preve"...
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The adverse reaction information from clinical trials does, however, provide a basis for identifying the adverse events that appear to be related to drug use and for approximating rates.
Studies with Exforge
Exforge has been evaluated for safety in over 2600 patients with hypertension; over 1440 of these patients were treated for at least 6 months and over 540 of these patients were treated for at least 1 year. Adverse reactions have generally been mild and transient in nature and have only infrequently required discontinuation of therapy.
The hazards [see WARNINGS AND PRECAUTIONS] of valsartan are generally independent of dose; those of amlodipine are a mixture of dose-dependent phenomena (primarily peripheral edema) and dose-independent phenomena, the former much more common than the latter.
The overall frequency of adverse reactions was neither dose-related nor related to gender, age, or race. In placebo-controlled clinical trials, discontinuation due to side effects occurred in 1.8% of patients in the Exforgetreated patients and 2.1% in the placebo-treated group. The most common reasons for discontinuation of therapy with Exforge were peripheral edema (0.4%), and vertigo (0.2%).
The adverse reactions that occurred in placebo-controlled clinical trials in at least 2% of patients treated with Exforge but at a higher incidence in amlodipine/valsartan patients (n=1437) than placebo (n=337) included peripheral edema (5.4% vs 3.0%), nasopharyngitis (4.3% vs 1.8%), upper respiratory tract infection (2.9% vs 2.1%) and dizziness (2.1% vs 0.9%).
Orthostatic events (orthostatic hypotension and postural dizziness) were seen in less than 1% of patients.
Other adverse reactions that occurred in placebo-controlled clinical trials with Exforge ( ≥ 0.2%) are listed below. It cannot be determined whether these events were causally related to Exforge.
Blood and Lymphatic System Disorders: Lymphadenopathy
Ear and Labyrinth Disorders: Ear pain
Immune System Disorders: Seasonal allergies
Psychiatric Disorders: Insomnia, anxiety, depression
Reproductive System and Breast Disorders: Erectile dysfunction
Vascular Disorders: Flushing, hot flush Isolated cases of the following clinically notable adverse reactions were also observed in clinical trials: exanthema, syncope, visual disturbance, hypersensitivity, tinnitus, and hypotension.
Studies with Amlodipine
Norvasc®* has been evaluated for safety in more than 11000 patients in U.S. and foreign clinical trials. Other adverse events that have been reported < 1% but > 0.1% of patients in controlled clinical trials or under conditions of open trials or marketing experience where a causal relationship is uncertain were:
General: allergic reaction, hot flushes, malaise, rigors, weight gain, weight loss
Musculoskeletal System: arthrosis, muscle cramps
Psychiatric: sexual dysfunction (male and female), nervousness, abnormal dreams, depersonalization
Respiratory System: dyspnea
Skin and Appendages: angioedema, erythema multiforme, rash erythematous, rash maculopapular
Autonomic Nervous System: sweating increased
Metabolic and Nutritional: hyperglycemia, thirst
Other events reported with amlodipine at a frequency of ≤ 0.1% of patients include: cardiac failure, pulse irregularity, extrasystoles, skin discoloration, urticaria, skin dryness, alopecia, dermatitis, muscle weakness, twitching, ataxia, hypertonia, migraine, cold and clammy skin, apathy, agitation, amnesia, gastritis, increased appetite, loose stools, rhinitis, dysuria, polyuria, parosmia, taste perversion, abnormal visual accommodation, and xerophthalmia. Other reactions occurred sporadically and cannot be distinguished from medications or concurrent disease states such as myocardial infarction and angina.
Adverse reactions reported for amlodipine for indications other than hypertension may be found in the prescribing information for Norvasc.
Studies with Valsartan
Diovan® has been evaluated for safety in more than 4000 hypertensive patients in clinical trials. In trials in which valsartan was compared to an ACE inhibitor with or without placebo, the incidence of dry cough was significantly greater in the ACE inhibitor group (7.9%) than in the groups who received valsartan (2.6%) or placebo (1.5%). In a 129-patient trial limited to patients who had had dry cough when they had previously received ACE inhibitors, the incidences of cough in patients who received valsartan, HCTZ, or lisinopril were 20%, 19%, and 69% respectively (p < 0.001).
Other adverse reactions, not listed above, occurring in > 0.2% of patients in controlled clinical trials with valsartan are:
Body as a Whole: allergic reaction, asthenia
Musculoskeletal: muscle cramps
Neurologic and Psychiatric: paresthesia
Respiratory: sinusitis, pharyngitis
Other reported events seen less frequently in clinical trials were: angioedema. Adverse reactions reported for valsartan for indications other than hypertension may be found in the prescribing information for Diovan.
Clinical Lab Test Findings
Creatinine: In hypertensive patients, greater than 50% increases in creatinine occurred in 0.4% of patients receiving Exforge and 0.6% receiving placebo. In heart failure patients, greater than 50% increases in creatinine were observed in 3.9% of valsartan-treated patients compared to 0.9% of placebo-treated patients. In post-myocardial infarction patients, doubling of serum creatinine was observed in 4.2% of valsartan-treated patients and 3.4% of captopril-treated patients.
Liver Function Tests: Occasional elevations (greater than 150%) of liver chemistries occurred in Exforgetreated patients.
Serum Potassium: In hypertensive patients, greater than 20% increases in serum potassium were observed in 2.8% of Exforge-treated patients compared to 3.4% of placebo-treated patients. In heart failure patients, greater than 20% increases in serum potassium were observed in 10% of valsartan-treated patients compared to 5.1% of placebo-treated patients.
Blood Urea Nitrogen (BUN): In hypertensive patients, greater than 50% increases in BUN were observed in 5.5% of Exforge-treated patients compared to 4.7% of placebo-treated patients. In heart failure patients, greater than 50% increases in BUN were observed in 16.6% of valsartan-treated patients compared to 6.3% of placebo-treated patients.
Neutropenia: Neutropenia was observed in 1.9% of patients treated with Diovan and 0.8% of patients treated with placebo.
Amlodipine: Gynecomastia has been reported infrequently and a causal relationship is uncertain. Jaundice and hepatic enzyme elevations (mostly consistent with cholestasis or hepatitis), in some cases severe enough to require hospitalization, have been reported in association with use of amlodipine.
Valsartan: The following additional adverse reactions have been reported in postmarketing experience with valsartan:
Hypersensitivity: There are rare reports of angioedema. Some of these patients previously experienced angioedema with other drugs including ACE inhibitors. Exforge should not be re-administered to patients who have had angioedema.
Digestive: Elevated liver enzymes and very rare reports of hepatitis
Renal: Impaired renal function, renal failure
Clinical Laboratory Tests: Hyperkalemia
Dermatologic: Alopecia, bullous dermatitis
Read the Exforge (amlodipine and valsartan) Side Effects Center for a complete guide to possible side effects
No drug interaction studies have been conducted with Exforge and other drugs, although studies have been conducted with the individual amlodipine and valsartan components.
Impact of Other Drugs on Amlodipine
Co-administration with CYP3A inhibitors (moderate and strong) results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is co-administered with CYP3A inhibitors to determine the need for dose adjustment [see CLINICAL PHARMACOLOGY].
No information is available on the quantitative effects of CYP3A inducers on amlodipine. Blood pressure should be closely monitored when amlodipine is co-administered with CYP3A inducers.
Monitor for hypotension when sildenafil is co-administered with amlodipine [see CLINICAL PHARMACOLOGY].
Impact of Amlodipine on Other Drugs
Co-administration of simvastatin with amlodipine increases the systemic exposure of simvastatin. Limit the dose of simvastatin in patients on amlodipine to 20 mg daily [see CLINICAL PHARMACOLOGY].
Amlodipine may increase the systemic exposure of cyclosporine or tacrolimus when co-administered. Frequent monitoring of trough blood levels of cyclosporine and tacrolimus is recommended and adjust the dose when appropriate [see CLINICAL PHARMACOLOGY].
No clinically significant pharmacokinetic interactions were observed when valsartan was coadministered with amlodipine, atenolol, cimetidine, digoxin, furosemide, glyburide, hydrochlorothiazide, or indomethacin. The valsartan-atenolol combination was more antihypertensive than either component, but it did not lower the heart rate more than atenolol alone.
Warfarin: Coadministration of valsartan and warfarin did not change the pharmacokinetics of valsartan or the time-course of the anticoagulant properties of warfarin.
Non-Steroidal Anti-Inflammatory Agents including Selective Cyclooxygenase-2 Inhibitors (COX-2 Inhibitors): In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of NSAIDs, including selective COX-2 inhibitors, with angiotensin II receptor antagonists, including valsartan, may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving valsartan and NSAID therapy.
The antihypertensive effect of angiotensin II receptor antagonists, including valsartan, may be attenuated by NSAIDs including selective COX-2 inhibitors.
Potassium: Concomitant use of valsartan with other agents that block the renin-angiotensin system, potassium-sparing diuretics (e.g., spironolactone, triamterene, amiloride), potassium supplements, salt substitutes containing potassium or other drugs that may increase potassium levels (e.g., heparin) may lead to increases in serum potassium and in heart failure patients to increases in serum creatinine. If co-medication is considered necessary, monitoring of serum potassium is advisable.
CYP 450 Interactions: In vitro metabolism studies indicate that CYP 450 mediated drug interactions between valsartan and coadministered drugs are unlikely because of low extent of metabolism [see Pharmacokinetics, Valsartan].
Transporters: The results from an in vitro study with human liver tissue indicate that valsartan is a substrate of the hepatic uptake transporter OATP1B1 and the hepatic efflux transporter MRP2. Coadministration of inhibitors of the uptake transporter (rifampin, cyclosporine) or efflux transporter (ritonavir) may increase the systemic exposure to valsartan.
Dual Blockade of the Renin-Angiotensin System (RAS): 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 Exforge and other agents that affect the RAS.
Do not coadminister aliskiren with Exforge in patients with diabetes. Avoid use of aliskiren with Exforge in patients with renal impairment (GFR < 60 mL/min).
Lithium: Increases in serum lithium concentrations and lithium toxicity have been reported during concomitant administration of lithium with angiotensin II receptor antagonists, including valsartan. Monitor serum lithium levels during concomitant use.
Read the Exforge Drug Interactions Center for a complete guide to possible interactions
Last reviewed on RxList: 8/14/2015
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