Acetohydroxamic acid and Enalaprilat/Enalapril Maleate

• Generic Name: acetohydroxamic acid
• Dosage Forms: n.a.
• Other Brand Names: Lithostat

Acetohydroxamic acid helps prevent a build-up of ammonia in urine that can be caused by a bladder infection. Increased ammonia in urine can cause the growth of kidney stones.

Acetohydroxamic acid is used to keep urine ammonia levels low in people who have a certain type of chronic bladder infection.

Acetohydroxamic acid is not an antibiotic and will not treat the infection itself. acetohydroxamic acid is only part of a treatment program that may also include antibiotics to treat the infection, and surgery to remove kidney stones. Follow your doctor's instructions very closely.

Acetohydroxamic acid may also be used for purposes not listed in this medication guide.

• Generic Name: enalapril
• Dosage Forms: n.a.
• Other Brand Names: Epaned, Vasotec

Management of hypertension (alone or in combination with other classes of antihypertensive agents). May use enalaprilat when oral therapy is not practical.

ACE inhibitors are recommended as one of several preferred agents for the initial management of hypertension according to current evidence-based hypertension guidelines; other preferred options include angiotensin II receptor antagonists, calcium-channel blockers, and thiazide diuretics. While there may be individual differences with respect to recommendations for initial drug selection and use in specific patient populations, current evidence indicates that these antihypertensive drug classes all generally produce comparable effects on overall mortality and cardiovascular, cerebrovascular, and renal outcomes.

Individualize choice of therapy; consider patient characteristics (e.g., age, ethnicity/race, comorbidities, cardiovascular risk) as well as drug-related factors (e.g., ease of administration, availability, adverse effects, cost).

A 2017 ACC/AHA multidisciplinary hypertension guideline classifies BP in adults into 4 categories: normal, elevated, stage 1 hypertension, and stage 2 hypertension.

Source: Whelton PK, Carey RM, Aronow WS et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2018;71:e13-115.

Individuals with SBP and DBP in 2 different categories (e.g., elevated SBP and normal DBP) should be designated as being in the higher BP category (i.e., elevated BP).

The goal of hypertension management and prevention is to achieve and maintain optimal control of BP. However, the BP thresholds used to define hypertension, the optimum BP threshold at which to initiate antihypertensive drug therapy, and the ideal target BP values remain controversial.

The 2017 ACC/AHA hypertension guideline generally recommends a target BP goal (i.e., BP to achieve with drug therapy and/or nonpharmacologic intervention) of <130/80 mm Hg in all adults regardless of comorbidities or level of atherosclerotic cardiovascular disease (ASCVD) risk. In addition, an SBP goal of <130 mm Hg generally is recommended for noninstitutionalized ambulatory patients ≥65 years of age with an average SBP of ≥130 mm Hg. These BP goals are based upon clinical studies demonstrating continuing reduction of cardiovascular risk at progressively lower levels of SBP.

Other hypertension guidelines generally have based target BP goals on age and comorbidities. Guidelines such as those issued by the JNC 8 expert panel generally have targeted a BP goal of <140/90 mm Hg regardless of cardiovascular risk and have used higher BP thresholds and target BPs in elderly patients compared with those recommended by the 2017 ACC/AHA hypertension guideline.

Some clinicians continue to support previous target BPs recommended by JNC 8 due to concerns about the lack of generalizability of data from some clinical trials (e.g., SPRINT study) used to support the current ACC/AHA hypertension guideline and potential harms (e.g., adverse drug effects, costs of therapy) versus benefits of BP lowering in patients at lower risk of cardiovascular disease.

Consider potential benefits of hypertension management and drug cost, adverse effects, and risks associated with the use of multiple antihypertensive drugs when deciding a patient’s BP treatment goal.

For decisions regarding when to initiate drug therapy (BP threshold), the current ACC/AHA hypertension guideline incorporates underlying cardiovascular risk factors. ASCVD risk assessment recommended by ACC/AHA for all adults with hypertension.

ACC/AHA currently recommend initiation of antihypertensive drug therapy in addition to lifestyle/behavioral modifications at an SBP ≥140 mm Hg or DBP ≥ 90 mm Hg in adults who have no history of cardiovascular disease (i.e., primary prevention) and a low ASCVD risk (10-year risk <10%).

For secondary prevention in adults with known cardiovascular disease or for primary prevention in those at higher risk for ASCVD (10-year risk ≥10%), ACC/AHA recommend initiation of antihypertensive drug therapy at an average SBP ≥130 mm Hg or an average DBP ≥80 mm Hg.

Adults with hypertension and diabetes mellitus, chronic kidney disease (CKD), or age ≥65 years of age are assumed to be at high risk for cardiovascular disease; ACC/AHA state that such patients should have antihypertensive drug therapy initiated at a BP ≥130/80 mm Hg.

Individualize drug therapy in patients with hypertension and underlying cardiovascular or other risk factors.

In stage 1 hypertension, experts state that it is reasonable to initiate drug therapy using the stepped-care approach in which one drug is initiated and titrated and other drugs are added sequentially to achieve the target BP. Initiation of antihypertensive therapy with 2 first-line agents from different pharmacologic classes recommended in patients with stage 2 hypertension and average BP >20/10 mm Hg above BP goal.

Black hypertensive patients generally tend to respond better to monotherapy with calcium-channel blockers or thiazide diuretics than to ACE inhibitors. However, the combination of an ACE inhibitor or an angiotensin II receptor antagonist with a calcium-channel blocker or thiazide diuretic produces similar BP lowering in black patients as in other racial groups.

ACE inhibitors may be preferred in hypertensive patients with heart failure, ischemic heart disease, diabetes mellitus, CKD, or cerebrovascular disease or post-MI.

Enalaprilat has been used effectively to control BP in adults with severe hypertension or hypertensive emergencies. However, for treatment of hypertensive emergencies, some clinicians prefer short-acting antihypertensive agents administered by continuous IV infusion for greater ease in titrating dosage to promptly but gradually reduce BP.

Heart Failure

Management of heart failure, usually in conjunction with other agents such as cardiac glycosides, diuretics, and β-adrenergic blocking agents (β-blockers).

Some evidence indicates that therapy with an ACE inhibitor may be less effective than angiotensin receptor-neprilysin inhibitor (ARNI) therapy (e.g., sacubitril/valsartan) in reducing cardiovascular death and heart failure-related hospitalization.

ACCF, AHA, and the Heart Failure Society of America (HFSA) recommend that patients with chronic symptomatic heart failure and reduced left ventricular ejection fraction (LVEF) (NYHA class II or III) who are able to tolerate an ACE inhibitor or angiotensin II receptor antagonist be switched to therapy containing an ARNI to further reduce morbidity and mortality.

Asymptomatic Left Ventricular Dysfunction

Treatment of clinically stable asymptomatic patients with left ventricular dysfunction (ejection fraction ≤35%) to improve survival and to reduce the incidence of overt heart failure and subsequent hospitalizations for heart failure.

Left Ventricular Dysfunction After Acute MI

ACE inhibitors, including enalapril and enalaprilat, have been used to reduce mortality and prevent the development of left ventricular dilatation and dysfunction following acute MI.

Expert guidelines recommend initiation of an oral ACE inhibitor within the first 24 hours of acute MI in patients with an anterior infarct, heart failure, or ejection fraction ≤40% who do not have any contraindications (e.g., hypotension, shock, renal dysfunction). Use with caution (and with gradual upward titration) during initial postinfarction period because of the possibility of hypotension or renal dysfunction.

Continue therapy indefinitely in patients with left ventricular dysfunction or other compelling indications (e.g., hypertension, diabetes mellitus, CKD).

Diabetic Nephropathy

A recommended agent in the management of patients with diabetes mellitus and persistent albuminuria who have modestly elevated (30–300 mg/24 hours) or higher (>300 mg/24 hours) levels of urinary albumin excretion; slows rate of progression of renal disease in such patients.