ACE inhibitors cough

Besides hypotension, the most frequent adverse reaction to an ACE inhibitor is cough, which may occur in up to 30% of patients. Patients with an ACE inhibitor cough and either clinical signs of heart failure or LVEF less than 40% may be prescribed an ARB.3 Other, less common but more serious adverse effects to ACE inhibitors and ARBs include acute renal failure, hyperkalemia, and angioedema. 

An angiotensin receptor blocker may be prescribed for patients with ACE inhibitor cough and a low LVEF and heart failure after MI. Example doses include the following ... 

Chili pepper (Capsicum spp.) ACE inhibitor Cough Capsaicin depletes substance P... 

Fox AJ, Lalloo UG, Belvisi MG, Bemareggi M, Chung KF, Bames PJ (1996) Bradykinin-evoked sensitization of airway sensory nerves A mechanism for ACE-inhibitor cough. Nat Med 2 814-817... 

Yeo, W. W, I. Chadwick, M. Kraskiewicz, P. Jackson, and L. Ramsay. 1995. Resolution of ACE inhibitor cough Changes in subjective cough and responses to inhaled capsaicin, intradermal brady-kinin and substance-P. Br.). Clin. Pharmacol. 40(5) 423-429. 

ACE inhibitors can be administered with diuretics (qv), cardiac glycosides, -adrenoceptor blockers, and calcium channel blockers. Clinical trials indicate they are generally free from serious side effects. The effectiveness of enalapril, another ACE inhibitor, in preventing patient mortaUty in severe (Class IV) heart failure was investigated. In combination with conventional dmgs such as vasodilators and diuretics, a 40% reduction in mortaUty was observed after six months of treatment using 2.5—40 mg/d of enalapril (141). However, patients complain of cough, and occasionally rash and taste disturbances can occur. 

However, it is also the major reason for the adverse side effects of ACE inhibitors, namely cough and angio-oedema. Another observed side effect, first-dose orthostatic hypotension, is probably due to both angiotensin inhibition and kinin potentiation. 

ADMINISTERING ACE INHIBITORS. The nurse administers captopril and moexipril 1 hour before or 2 hours after meals to enhance absorption. Some patients taking an ACE inhibitor experience a dry cough that does not subside until the drug therapy is discontinued. This reaction may need to be tolerated. If the cough becomes too bothersome, the primary care provider may discontinue use of the drug. 

Despite their clear benefits, ACE inhibitors are still underutilized in HF. One reason is undue concern or confusion regarding absolute versus relative contraindications for their use. Absolute contraindications include a history of angioedema, bilateral renal artery stenosis, and pregnancy. Relative contraindications include unilateral renal artery stenosis, renal insufficiency, hypotension, hyperkalemia, and cough. Relative contraindications provide a warning that close monitoring is required, but they do not necessarily preclude their use. 

Angiotensin receptor blockers show similar tolerability to ACE inhibitors with regard to hypotension and hyperkalemia, but they do not induce cough since ARBs do not cause an accumulation of bradykinin. Angiotensin receptor blockers can be considered in patients with ACE inhibitor-induced angioedema, but they should be initiated cautiously, as crossreactivity has been reported. Many of the other considerations for the use of ARBs are similar to those of ACE inhibitors,... 

Angiotensi n-converti ng Hypotension, cough (with ACE inhibitors), BP every 2 hours x 3 for first dose, then every shift during oral... 

Cough and angioedema are the most common causes of ACE inhibitor intolerance. Caution should be exercised when ARBs are used in patients with angioedema from ACE inhibitors because cross-reactivity has been reported. ARBs are not alternatives in patients with hypotension, hyperkalemia, or renal insufficiency due to ACE inhibitors because they are just as likely to cause these adverse effects. 

Unlike ACE inhibitors, ARBs do not block the breakdown of bradykinin. While this accounts for the lack of cough as a side effect, there may be negative consequences because some of the antihypertensive effect of ACE inhibitors may be due to increased levels of bradykinin. Bradykinin may also be important for regression of myocyte hypertrophy and fibrosis, and increased levels of tissue plasminogen activator. 

ARBs appear to have the lowest incidence of side effects compared with other antihypertensive agents. Because they do not affect bradykinin, they do not cause a dry cough like ACE inhibitors. Like ACE inhibitors, they may cause renal insufficiency, hyperkalemia, and orthostatic hypotension. Angioedema is less likely to occur than with ACE inhibitors, but crossreactivity has been reported. ARBs should not be used in pregnancy. 

Undesired effects. The magnitude of the antihypertensive effect of ACE inhibitors depends on the functional state of the RAA system. When the latter has been activated by loss of electrolytes and water (resulting from treatment with diuretic drugs), cardiac failure, or renal arterial stenosis, administration of ACE inhibitors may initially cause an excessive fall in blood pressure. In renal arterial stenosis, the RAA system may be needed for maintaining renal function and ACE inhibitors may precipitate renal failure. Dry cough is a fairly frequent side effect, possibly caused by reduced inactivation of kinins in the bronchial mucosa. Rarely, disturbances of taste sensation, exanthema, neutropenia, proteinuria, and angioneurotic edema may occur. In most cases, ACE inhibitors are well tolerated and effective. Newer analogues include lisinopril, perindo-pril, ramipril, quinapril, fosinopril, benazepril, cilazapril, and trandolapril. 

Benazepril (Lotensin) [Antihypertensive/ACEI] Uses HTN DN, CHF Action ACE inhibitor Dose 10 0 mg/d PO Caution [C (1st tri), D (2nd 3rd tri), +] Contra Angioedema, Hx edema, bilateral RAS Disp Tabs 5, 10, 20, 40 mg SE Symptomatic i BP w/ diuretics dizziness, HA, nonproductive cough Interactions T Effects W/ a-blockers, diuretics, capsaicin effects W/ NSAIDs, ASA T effects OF insulin, Li T risk of hyperkalemia W/ trimethoprim K-sparing diuretics EMS Monitor EGG for signs of hyperkalemia angioedema is rare but can occur persistent cough /or taste changes may develop OD Profound hypotension treat w/ IV fluid... 

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