5.1     Anaphylactoid and Possibly Related Reactions

Presumably because angiotensin-converting enzyme inhibitors affect the metabolism of eicosanoids and polypeptides, including endogenous bradykinin, patients receiving ACE inhibitors (including Lotrel) may be subject to a variety of adverse reactions, some of them serious. These reactions usually occur after one of the first few doses of the ACE inhibitor, but they sometimes do not appear until after months of therapy. Black patients receiving ACE inhibitors have a higher incidence of angioedema compared to nonblacks.

Patients receiving coadministration of ACE inhibitor and mTOR (mammalian target of rapamycin) inhibitor (e.g., temsirolimus, sirolimus, everolimus) therapy may be at increased risk for angioedema [see Drug Interactions (7)].

Head and Neck Angioedema: Angioedema of the face, extremities, lips, tongue, glottis, and larynx has been reported in patients treated with ACE inhibitors. In U.S. clinical trials, symptoms consistent with angioedema were seen in none of the subjects who received placebo and in about 0.5% of the subjects who received benazepril. Angioedema associated with laryngeal edema can be fatal. If laryngeal stridor or angioedema of the face, tongue, or glottis occurs, discontinue treatment with Lotrel and treat  immediately. When involvement of the tongue, glottis, or larynx appears likely to cause airway obstruction, appropriate therapy, e.g., administer subcutaneous epinephrine injection 1:1000 (0.3 to 0.5 mL), promptly [see Adverse Reactions (6)].

Intestinal Angioedema: Intestinal angioedema has been reported in patients treated with ACE inhibitors. These patients presented with abdominal pain (with or without nausea or vomiting); in some cases there was no prior history of facial angioedema and C-1 esterase levels were normal. The angioedema was diagnosed by procedures including abdominal CT scan or ultrasound, or at surgery, and symptoms resolved after stopping the ACE inhibitor. Intestinal angioedema should be included in the differential diagnosis of patients on ACE inhibitors presenting with abdominal pain.

Anaphylactoid Reactions During Desensitization: Two patients undergoing desensitizing treatment with hymenoptera (wasp sting) venom while receiving ACE inhibitors sustained life-threatening anaphylactoid reactions. In the same patients, these reactions were avoided when ACE inhibitors were temporarily withheld, but they reappeared upon inadvertent rechallenge.

Anaphylactoid Reactions During Membrane Exposure: Anaphylactoid reactions have been reported in patients dialyzed with high-flux membranes and treated concomitantly with an ACE inhibitor. Anaphylactoid reactions have also been reported in patients undergoing low-density lipoprotein apheresis with dextran sulfate absorption.

5.2     Increased Angina and/or Myocardial Infarction

Worsening angina and acute myocardial infarction can develop after starting or increasing the dose of amlodipine, particularly in patients with severe obstructive coronary artery disease.

5.3     Patients with Aortic and Mitral Valve Stenosis, Obstructive Hypertrophic Cardiomyopathy

As with all other vasodilators, special caution is required when using amlodipine in patients suffering from aortic or mitral stenosis, or obstructive hypertrophic cardiomyopathy.

5.4     Hypotension

Lotrel can cause symptomatic hypotension. Symptomatic hypotension is most likely to occur in patients who have been volume or salt depleted as a result of diuretic therapy, dietary salt restriction, dialysis, diarrhea, or vomiting. Volume and/or salt depletion should be corrected before starting therapy with benazepril. If hypotension occurs, the patient should be placed in the supine position and if necessary given physiological saline intravenously. Treatment with benazepril can be continued once blood pressure and volume have returned to normal.

In patients with congestive heart failure, with or without associated renal insufficiency, ACE inhibitor therapy may cause excessive hypotension, which may be associated with oliguria, azotemia, and (rarely) with acute renal failure and death. In such patients, start Lotrel therapy under close medical supervision; follow closely for the first 2 weeks of treatment and whenever the dose of the benazepril component is increased or a diuretic is added or its dose increased.

Symptomatic hypotension is also possible in patients with severe aortic stenosis.

5.5     Fetal Toxicity

Pregnancy Category D

Use of drugs that act on the RAS during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Potential neonatal adverse effects include skull hypoplasia, anuria, hypotension, renal failure, and death. When pregnancy is detected, discontinue Lotrel as soon as possible [see Use in Specific Populations (8.1)].

5.6     Hepatitis and Hepatic Failure

There have been rare reports of predominantly cholestatic hepatitis and isolated cases of acute liver failure, some of them fatal, in patients on ACE inhibitors. The mechanism is not understood. Patients receiving ACE inhibitors who develop jaundice or marked elevation of hepatic enzymes should discontinue the ACE inhibitor and be kept under medical surveillance.

5.7     Impaired Renal Function

Monitor renal function periodically in patients treated with Lotrel. Changes in renal function, including acute renal failure, can be caused by drugs that affect the RAS. Patients whose renal function may depend in part on the activity of the RAS (e.g., patients with renal artery stenosis, severe heart failure, post-myocardial infarction or volume depletion) or who are on NSAIDS or ARBs may be at particular risk of developing acute renal failure on Lotrel. Consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function on Lotrel.

5.8     Hyperkalemia

Monitor serum potassium periodically in patients receiving Lotrel. Drugs that affect the RAS can cause hyperkalemia. Risk factors for the development of hyperkalemia include renal insufficiency, diabetes mellitus, and the concomitant use of potassium-sparing diuretics, potassium supplements, and/or potassium-containing salt substitutes. In U.S. placebo-controlled trials of Lotrel, hyperkalemia [serum potassium at least 0.5 mEq/L greater than the upper limit of normal (ULN)] not present at baseline occurred in approximately 1.5% of hypertensive patients receiving Lotrel. Increases in serum potassium were generally reversible.