Enalaprilat (Intravenous)

Enalaprilat is the active metabolite of the orally available pro-drug called enalapril, which is used in the treatment of high blood pressure (BP) in patients.


Enalaprilat's sole purpose is to treat hypertension in patients. High blood pressure usually overwhelms the workload and functionality of the heart and arteries. This means that, if allowed to continue for an extended period, both the arteries and heart may not function properly and may end up damaging the blood vessels of the heart, brain, and kidneys. A person may also get a stroke, kidney failure, heart failure, and subsequent episodes of potential heart attacks. However, it's very hard for these health complications to occur in patients when their blood pressure is under control.

Enalaprilat is very effective in patients with high-renin levels of hypertension and may produce a dramatic drop in blood pressure in patients that are volume-depleted by a previous diuretic or dietary sodium restriction therapy.

Enalaprilat works by blocking an enzyme in the body, a mechanism that produces a substance which causes blood vessels to contract. Once the blood vessels relax, the patient experiences low or optimum blood pressure and the supply of blood and oxygen around the body also increases. Nevertheless, African-Americans may respond poorly to this drug due to their low renin levels.

Because this medicine may induce potential hypotension in volume-depleted patients, it should be used with caution in patients who are at high risk of experiencing a cerebral hypotensive episode. All the same, this medication is available to patients only with a physician's prescription and usually comes in a solution dosage form.

Conditions Treated?

  • Heart attack

Type Of Medicine?

  • ACE inhibitor

Side Effects

Enalaprilat may cause some unwanted side effects in patients. Therefore, a patient should check with his or her doctor or nurse immediately if they notice any of the following side effects while taking this medication.

  • Confusion
  • Blurred vision
  • Dizziness, passing out, or lightheadedness when getting up from a sitting or lying position
  • Body fatigue
  • Sweating


  • Nausea
  • Pain or discomfort in jaw, arms, neck, or back
  • Shortness of breath
  • Vomiting

Less common

  • Rash
  • Difficulty passing a bowel movement

Some patients may experience other side effects besides the ones found on this list. Therefore, patients should check with their healthcare provider if they notice any unusual changes in their body. Patients may also call their doctor for medical advice about side effects or may report them to the FDA at 1-800-FDA-1088.


A) For intravenous administration only

The dose given to hypertensive patients is 1.25 mg every 6 hours and is usually administered intravenously over a 5-minute period. A clinical response is experienced within the first 15 minute. Substantial effects after the first dose may not occur for up to 4 hours straight after dosing. Sometimes, the peak effects of the second and other subsequent doses may exceed the first doses.

No dosage regimen for VASOTEC I.V. has been found to be more effective in treating heart attack than 1.25 mg every 6 hours. However, studies in hypertension suggest that doses as high as 5 mg every 6 hours can be well tolerated by patients for about 36 hours. The dose for patients being switched to VASOTEC I.V. from oral therapy for hypertension is 1.25 mg every 6 hours. For patients being converted from intravenous to oral therapy, the recommended dose of VASOTEC tablets is 5 mg a day with subsequent dosage changes as usual.

B) Patients on diuretic therapy

The recommended initial dose for heart attack is 0.625 mg, which is administered intravenously over a 5-minute period. A clinical response is experienced within the first 15 minutes after treatment. Substantial effects after the first dose may not occur for up to 4 hours after dosage, although some patients may see most of the drug's effect within the first hour. If an hour lapses and no substantial clinical response is established, an additional 0.625 mg dose should be administered. Also, another 1.25 mg dose may be given at 6-hour intervals.

For patients being converted from intravenous to oral therapy, after responding to the drugs 0.625 mg dose, the initial dose of VASOTEC tablets is 2.5 mg a day with subsequent dosage changes as usual.

C) Dosage adjustment in renal impairment

The usual dose of 1.25 mg every 6 hours is highly recommended for patients with a creatinine clearance >30 mL/min (serum creatine about 3 mg/dL). For patients with creatinine clearance about 3 mg/dL, their starting dose is usually 0.625 mg. If a patient doesn't show any substantive clinical response, the 0.625 mg dose should be repeated. Further additional doses of 1.25 mg may be given every 6 hours.

For patients converted from intravenous to oral therapy, the recommended starting dose of VASOTEC tablets is 5 mg a day for patients with creatinine clearance >30 mL/min, and 2.5 mg at least once every day for patients with creatinine clearance.

D) Patients at risk of excessive hypotension

Patients at a high risk of excessive hypotension are those who exhibit any of the following conditions or characteristics--hyponatremia, heart failure, high dose of diuretic therapy, increase in diuretic dose, recent intensive diuresis, and renal dialysis.

Single doses of enalaprilat medicine as low as 0.2 mg have produced increased hypotension in many patients with these diagnoses. Such patients should start therapy right away under heavy surveillance of a healthcare provider to effectively mitigate any extreme hypotensive responses. The initial dose should be no greater than 0.625 mg and should be given intravenously over a period not less than 5 minutes. All the same, patients at risk of excessive hypotension should be followed closely whenever their dose and diuretic levels are adjusted.

Caution: Patients who think were given an overdose should call the poison control center nearby or get medical care straight away. Consequently, a patient should be ready to explain to their nurse or doctor about the kind of drug they took, in what quantities (large or small), and when that incidence actually happened.

Drug interactions

1. Hypotension - Patients on diuretics therapy, particularly those in whom the therapy was recently instituted, may occasionally have a high reduction of blood pressure after being treated with enalaprilat. The hypotensive effects can only be minimized by discontinuing diuretic therapy, administration of an intravenous infusion of normal saline, or increasing salt intake levels before starting enalaprilat treatment. It's important for healthcare providers to provide close medical supervision for at least an hour after giving a patient the first dose of enalaprilat.

2. Risk of renin production - The antihypertensive effect of VASOTEC I.V. appears to carry a lot of hypertensive agents that may pose a big threat to patients being exposed to renin.

3. Non-steroidal anti-inflammatory agents - Some individuals with a comprised renal function and are receiving non-steroidal anti-inflammatory drugs, may deteriorate the renal function much further after starting enalapril treatment. Fortunately, these effects are usually reversible so patients shouldn't worry.

4. Agents increasing serum potassium - Some agents found in VASOTEC I.V. such as potassium supplements, potassium-containing salt substitutes, or potassium-sparing diuretics may result in huge increases in serum potassium in patients. Healthcare providers giving this treatment should use lots of caution and keep track of the serum potassium levels.

5. Lithium - Lithium toxicity levels are widespread in patients taking enalapril together with lithium, though the effects usually fade upon withdrawal of both drugs. The side effect may also be suppressed by NSAIDS. It's important for healthcare professionals to frequently check serum lithium levels in patients if enalapril is dispensed together with lithium.

6. Episodes of contraindications - VASOTEC I.V. is usually contraindicated in patients with a history of angioedema, patients that are hypersensitive to any part of this medication, and patients either with idiopathic or hereditary angioedema.


  • If a patient's health problems or symptoms do not get better or continue to worsen, a doctor should be called right away.
  • A patient should not share this drug with anyone, neither should he or she take anyone else's drugs.
  • Patients should keep a list of all their drugs (prescription, vitamins, natural products, OTC) and should also make a copy for their healthcare provider.
  • Patients should first talk with their doctor before starting any new medication.
  • Patients should keep all drugs in a safe place away from children and pets.
  • Patients should check with their pharmacists about how to throw away expired or unused drugs.
  • Some drugs usually have another patient information leaflet. Therefore, patients should check with their pharmacist, nurse, doctor, or other healthcare providers if they've any questions about enalaprilat.
  • If a person fears he or she was given an overdose, they should call the poison control center nearby or get medical care right away.
  • Do not give this drug to an infant younger than 1 month of age. A patient should not take this drug while pregnant, as this may likely cause birth defects or loss of the unborn child. A patient should call their doctor right away if pregnant or are planning to get a baby while taking enalapril treatment.
  • Even though VASOTEC I.V may be effective in reducing hypertension in patients, its ACE inhibitors make a small difference on blood pressure of African American patients than in whites. This means African Americans receiving ACE inhibitors are usually at a higher risk of getting angioedema compared to whites.
  • Patients should also talk with their healthcare provider for further information about the benefits and risks involved in taking enalaprilat medication.


  • Store this drug below room temperature at around 25°C (77°F) all the time


Enalaprilat drug is an ACE inhibitor and is used in the treatment of high blood pressure in patients. In fact, it's the only available angiotensin-changing enzyme (ACE) inhibitor that can be given intravenously. This drug lowers blood pressure within 15-30 minutes, but the blood pressure response in hypertensive emergencies is unpredictable, in part because of variable degrees of plasma expansion.

The most widespread severe side effect a patient can experience is hypotension. The risk for hypotension further progresses in patients with evidence of renal hypertension, patients with prior use of diuretics, and in volume-depleted patients. Moreover, enalaprilat drug is contraindicated in patients with unilateral stenosis of a single kidney or in patients with evidence of bilateral renal artery stenosis. In other words, this drug is particularly useful in hypertensive emergencies related to high renin levels or congestive heart failure, and can easily be substituted by oral enalapril for long-term maintenance therapy.

Enalaprilat injection is effective in that it results in the reduction of both supine and standing systolic and diastolic blood pressure. No orthostatic element is present, which means the occurrence of symptomatic postural hypotension in patients is very minimal but may be frequent in volume-depleted patients. Patients may start noticing this medicine's effect within the first fifteen minutes of administration and may likely experience its full effect within 1 to 4 hours.

The abrupt withdrawal or discontinue use of the drug has not been linked with a rapid increase in blood pressure. The hemodynamic effects that appear in patients, many times are usually dose-related. The recommended dose given to patients lasts for about six hours before it begins to fade. All the same, following doctor's orders or prescription, a patient should experience reduced levels of blood pressure, increased levels of oxygen and blood supply, and better health.