Enalapril

Dosage for Enalapril must be highly individualized based on the patient's clinical response and the specific condition being treated.

• Hypertension: The usual starting dose for adults not taking diuretics is 5 mg once daily. Your healthcare provider may gradually increase this dose up to a maximum of 40 mg per day, administered as a single dose or divided into two equal doses. If you are already taking a diuretic, your doctor may start you on a lower dose of 2.5 mg to prevent a sudden drop in blood pressure.
• Heart Failure: The recommended initial dose is 2.5 mg once or twice daily. Because of the risk of significant hypotension (low blood pressure) after the first dose, this is often administered under medical supervision. The target maintenance dose is typically 20 mg per day, divided into two doses.
• Left Ventricular Dysfunction: The starting dose is 2.5 mg twice daily, titrated upward as tolerated to a target daily dose of 20 mg in divided doses.

Enalapril is approved for use in children with hypertension who are older than 1 month of age.

• Dosing Calculation: The typical starting dose is 0.08 mg/kg (up to 5 mg) once daily.
• Titration: The dosage should be adjusted according to the blood pressure response. Doses above 0.58 mg/kg (or in excess of 40 mg) have not been extensively studied in pediatric populations.
• Neonates: Enalapril is generally not recommended in neonates (infants under 1 month) or in pediatric patients with a glomerular filtration rate <30 mL/min/1.73 m² due to the lack of safety data.

Renal Impairment

Since Enalapril is primarily excreted by the kidneys, patients with reduced kidney function require lower doses. If your creatinine clearance is between 30 and 80 mL/min, the starting dose for hypertension is usually 5 mg. If it is less than 30 mL/min, the starting dose is typically reduced to 2.5 mg.

Hepatic Impairment

While the liver is responsible for converting Enalapril to its active form, specific dosage adjustment guidelines for hepatic impairment are not standardized. However, patients with severe liver disease should be monitored closely for delayed therapeutic onset.

Elderly Patients

Older adults may be more sensitive to the effects of Enalapril. Healthcare providers often start elderly patients on the lower end of the dosing spectrum (2.5 mg) to monitor for dizziness or kidney strain.

• Consistency: Take Enalapril at the same time each day to maintain steady levels in your bloodstream.
• Food: You may take this medication with or without food.
• Administration: Swallow the tablets whole with a glass of water. If you are using the oral solution, use a calibrated measuring device rather than a household spoon to ensure an accurate dose.
• Storage: Store the medication at room temperature (20°C to 25°C / 68°F to 77°F) in a dry place away from direct sunlight.

If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and return to your regular routine. Never take two doses at once to make up for a missed one, as this significantly increases the risk of severe hypotension.

Signs of an Enalapril overdose include extreme dizziness, lightheadedness, or fainting due to a massive drop in blood pressure. If an overdose is suspected, seek emergency medical attention immediately. Treatment in a hospital setting typically involves intravenous fluids to support blood pressure and, in severe cases, hemodialysis to remove enalaprilat from the blood.

> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking the medication without medical guidance, as stopping abruptly can cause your blood pressure to spike dangerously.

Many patients tolerate Enalapril well, but some may experience side effects as the body adjusts to the medication.

• Dry Cough: This is the most hallmark side effect of ACE inhibitors. It is typically a persistent, non-productive (dry) tickle in the throat. It occurs because the drug prevents the breakdown of bradykinin and substance P in the lungs. This cough usually does not respond to cough suppressants and may only resolve if the medication is discontinued.
• Dizziness and Lightheadedness: These symptoms are most common during the first few days of treatment or when the dose is increased, as the body adapts to lower blood pressure levels.

• Fatigue and Asthenia: A general feeling of tiredness or weakness.
• Orthostatic Hypotension: A sudden drop in blood pressure when standing up from a sitting or lying position, which can lead to fainting.
• Headache: Mild to moderate headaches may occur during the initiation of therapy.
• Nausea and Diarrhea: Mild gastrointestinal upset is occasionally reported.

• Hyperkalemia: Enalapril can cause the body to retain potassium. While often asymptomatic, severely high potassium levels can lead to dangerous heart rhythm disturbances.
• Proteinuria: The presence of excess protein in the urine, which may indicate changes in kidney function.
• Neutropenia/Agranulocytosis: A rare but serious decrease in white blood cells, which can make the body more susceptible to infections.
• Liver Enzyme Elevation: Rare cases of hepatitis or cholestatic jaundice have been reported.

> Warning: Stop taking Enalapril and call your doctor immediately if you experience any of the following serious symptoms.

1. 1Angioedema: This is a life-threatening allergic reaction characterized by swelling of the face, lips, tongue, and throat. It can block the airway and make breathing impossible. This risk is significantly higher in Black patients compared to other ethnic groups.
2. 2Kidney Failure: Symptoms include a significant decrease in urine output, swelling in the ankles or feet, and shortness of breath.
3. 3Liver Toxicity: Look for yellowing of the skin or eyes (jaundice), dark urine, and severe upper stomach pain.
4. 4Anaphylaxis: Severe allergic reactions including hives, difficulty breathing, and a rapid or weak pulse.
5. 5Chest Pain (Angina): While Enalapril is used for heart conditions, some patients may experience new or worsening chest pain during the start of therapy.

Prolonged use of Enalapril requires ongoing monitoring of renal function and electrolyte balance. Long-term use is generally safe, but some patients may develop a slow decline in kidney function over many years, especially if they have underlying renal artery stenosis (narrowing of the arteries to the kidneys).

Fetal Toxicity: Enalapril carries a strict FDA Black Box Warning regarding its use during pregnancy. When used in pregnancy during the second and third trimesters, ACE inhibitors can cause injury and even death to the developing fetus. Potential complications include skull hypoplasia (underdevelopment), anuria (lack of urine production), renal failure, and limb contractures. If pregnancy is detected, Enalapril must be discontinued as soon as possible. Discuss alternative blood pressure treatments with your doctor if you are planning to become pregnant.

Report any unusual symptoms to your healthcare provider immediately. Early detection of side effects can prevent serious complications.

Enalapril is a powerful cardiovascular medication that requires careful management. Patients must be aware that the first dose can cause a significant drop in blood pressure, especially if they are dehydrated or taking other diuretics. It is often recommended to take the first dose at bedtime to minimize the risk of fainting from dizziness.

Full Text Summary: Enalapril can cause serious injury or death to an unborn baby if taken during pregnancy. Use of drugs that act on the renin-angiotensin system during the second and third trimesters reduces fetal renal function and increases fetal and neonatal morbidity and death. Resulting oligohydramnios (low amniotic fluid) 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 Enalapril as soon as possible.

• Angioedema Risk: Patients with a history of angioedema (unrelated to ACE inhibitor therapy) may be at increased risk of angioedema while receiving an ACE inhibitor. This reaction can occur at any time during treatment, not just at the start.
• Hypotension (Low Blood Pressure): Excessive hypotension is rare in uncomplicated hypertensive patients but can occur in patients who are volume-depleted due to diuretic therapy, dietary salt restriction, dialysis, diarrhea, or vomiting.
• Impaired Renal Function: In patients with severe heart failure, whose renal function may depend on the activity of the RAAS, treatment with Enalapril may be associated with oliguria (low urine output) or progressive azotemia (high nitrogen levels in the blood).
• Anaphylactoid Reactions during Desensitization: Patients receiving ACE inhibitors during desensitizing treatment with hymenoptera (bee/wasp) venom have sustained life-threatening anaphylactoid reactions.
• Hepatic Failure: Rarely, ACE inhibitors have been associated with a syndrome that starts with cholestatic jaundice and progresses to fulminant hepatic necrosis and sometimes death.

Your healthcare provider will require regular lab tests to ensure the medication is working safely:

1. 1Serum Creatinine and BUN: To monitor kidney function.
2. 2Serum Potassium: To check for hyperkalemia (high potassium levels).
3. 3Blood Pressure Monitoring: Regular checks at home and in the clinic to ensure the dose is effective.
4. 4White Blood Cell Count: Occasionally monitored in patients with collagen vascular diseases (like Lupus) to check for neutropenia.

Because Enalapril can cause dizziness, especially during the first few days of treatment, you should avoid driving or operating heavy machinery until you know how the medication affects you. Fainting (syncope) can occur unexpectedly.

Alcohol can further lower your blood pressure, increasing the risk of dizziness, fainting, and falls. It is generally advised to limit or avoid alcohol consumption while taking Enalapril.

Do not stop taking Enalapril suddenly. While it does not typically cause a "withdrawal syndrome," your blood pressure may rise rapidly, increasing the risk of a stroke or heart attack. If you need to stop the medication, your doctor will provide a tapering schedule.

> Important: Discuss all your medical conditions, especially kidney disease, liver disease, or a history of allergic reactions, with your healthcare provider before starting Enalapril.

• Sacubitril/Valsartan (Entresto): You must not take Enalapril within 36 hours of taking a neprilysin inhibitor like sacubitril. Combining these increases the risk of life-threatening angioedema (severe swelling).
• Aliskiren: In patients with diabetes, the use of Enalapril with aliskiren is strictly contraindicated due to the high risk of kidney failure, hypotension, and hyperkalemia.

• Potassium-Sparing Diuretics: Drugs like spironolactone, triamterene, or amiloride can lead to dangerously high potassium levels (hyperkalemia) when combined with Enalapril.
• Potassium Supplements: Using potassium-containing salt substitutes or supplements can cause toxic levels of potassium in the blood.
• Lithium: Enalapril can decrease the renal clearance of lithium, leading to lithium toxicity. Symptoms include tremors, confusion, and muscle weakness.
• Dual Blockade of the RAAS: Combining Enalapril with an Angiotensin II Receptor Blocker (ARB) is generally avoided as it increases the risk of hypotension and renal impairment without providing significant additional benefit for most patients.

• Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): Medications like ibuprofen (Advil/Motrin), naproxen (Aleve), and celecoxib can reduce the blood-pressure-lowering effect of Enalapril. Furthermore, in patients who are elderly or have poor kidney function, the combination can lead to acute kidney failure.
• Diuretics (Water Pills): While often used together, the initial combination can cause a sharp drop in blood pressure. Your doctor may adjust your diuretic dose before starting Enalapril.
• Gold Therapy: Nitritoid reactions (symptoms include facial flushing, nausea, vomiting, and hypotension) have been reported rarely in patients on therapy with injectable gold (sodium aurothiomalate) and concomitant ACE inhibitor therapy.

• High-Potassium Foods: While a healthy diet is encouraged, excessive consumption of high-potassium foods (like bananas, oranges, and leafy greens) should be discussed with your doctor to avoid hyperkalemia.
• Salt Substitutes: Many salt substitutes contain potassium chloride instead of sodium chloride. These should be avoided unless approved by your healthcare provider.

• Natural Licorice: Can cause sodium retention and potassium loss, counteracting the effects of Enalapril.
• St. John's Wort: May theoretically alter the metabolism of various cardiovascular drugs, though specific data for Enalapril is limited.
• Garlic/Ginger: May have mild blood-pressure-lowering effects, which could potentially increase the risk of hypotension when combined with Enalapril.

Enalapril may cause a false-positive result in certain urine tests for acetone. It may also slightly increase serum bilirubin and liver enzymes, which could be misinterpreted during routine blood work.

> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking. A complete list helps prevent dangerous interactions.

Enalapril must NEVER be used in the following circumstances:

1. 1History of Angioedema: If you have ever experienced angioedema (swelling of the face, tongue, or airway) related to previous treatment with an ACE inhibitor, or if you have hereditary or idiopathic angioedema. The risk of a fatal recurrence is extremely high.
2. 2Pregnancy: Due to the proven risk of fetal toxicity and death, Enalapril is absolutely contraindicated in the second and third trimesters of pregnancy.
3. 3Hypersensitivity: If you have a known allergy to enalapril maleate or any other ACE inhibitor (such as lisinopril, ramipril, or benazepril).
4. 4Concomitant Use with Sacubitril: As noted in the interactions section, the use of Enalapril within 36 hours of sacubitril/valsartan is prohibited.

Healthcare providers will perform a careful risk-benefit analysis in the following cases:

• Renal Artery Stenosis: In patients with bilateral renal artery stenosis (narrowing of both arteries supplying the kidneys), Enalapril can cause a rapid decline in kidney function and acute renal failure.
• Aortic Stenosis: Patients with severe narrowing of the heart's aortic valve may be at risk for coronary hypoperfusion (low blood flow to the heart muscle) if their blood pressure drops too low.
• Hyperkalemia: Patients who already have high potassium levels should not start Enalapril until the electrolyte imbalance is corrected.
• Volume Depletion: Patients who are severely dehydrated or have very low sodium levels should be stabilized before starting Enalapril to prevent circulatory collapse.

There is a high degree of cross-sensitivity among ACE inhibitors. If you have had a severe allergic reaction to one drug in this class, you are highly likely to react to Enalapril. However, there is generally no cross-sensitivity between ACE inhibitors and other classes of blood pressure medications like Beta-blockers or Calcium Channel Blockers.

> Important: Your healthcare provider will evaluate your complete medical history, including any previous allergic reactions to medications, before prescribing Enalapril.

Enalapril is classified as Pregnancy Category D. There is clear evidence of human fetal risk based on adverse reaction data from investigational or marketing experience.

• First Trimester: While some data suggest a risk of cardiovascular malformations when taken in the first trimester, the evidence is less definitive than for the later stages.
• Second and Third Trimesters: Use during this period is known to cause fetal renal dysfunction, leading to low amniotic fluid (oligohydramnios). This results in fetal lung hypoplasia, skeletal deformities, and often death. If you become pregnant, stop the medication and contact your doctor immediately.

Enalapril and its active metabolite, enalaprilat, are excreted in human milk in very small amounts. While the risk to a healthy term infant is likely low, the safety in preterm infants has not been established. Mothers who are breastfeeding should consult their doctor; often, alternative medications with more safety data are preferred during the early months of breastfeeding.

Enalapril is approved for hypertension in children older than one month. It has been shown to be effective and generally well-tolerated in this population. However, it is not recommended for children with very poor kidney function (GFR <30 mL/min). Long-term effects on growth and development have not been specifically studied, but the drug has been used safely in pediatrics for decades.

Clinical studies did not identify overall differences in safety or effectiveness between elderly (65 and older) and younger patients. However, because older adults are more likely to have decreased renal function and take multiple medications (polypharmacy), they should be started on lower doses. There is an increased risk of falls in the elderly if Enalapril causes significant orthostatic hypotension (dizziness upon standing).

Patients with kidney disease require careful dose titration. Enalaprilat is removed by hemodialysis; on dialysis days, the dose should be administered after the procedure to ensure the drug remains in the system to control blood pressure. For those with a creatinine clearance less than 30 mL/min, the initial dose is reduced by 50%.

In patients with cirrhosis, the conversion of Enalapril to enalaprilat may be slowed, but the ultimate therapeutic effect is usually maintained. No specific starting dose adjustment is required for mild-to-moderate liver disease, but close monitoring for side effects is recommended.

> Important: Special populations require individualized medical assessment and frequent monitoring by a healthcare professional.

Enalapril maleate is an oral prodrug of the active ACE inhibitor, enalaprilat. Its primary molecular target is the Angiotensin-Converting Enzyme (ACE), a peptidyl dipeptidase.

• Molecular Path: ACE normally catalyzes the conversion of the decapeptide angiotensin I to the octapeptide angiotensin II. By binding to the active site of ACE, enalaprilat prevents this conversion.
• Hemodynamic Effect: The reduction in angiotensin II leads to decreased arterial vasoconstriction, decreased peripheral vascular resistance, and increased venous capacitance. This results in lowered blood pressure and reduced afterload on the heart.

• Onset of Action: Following oral administration, the antihypertensive effect typically begins within 1 hour.
• Peak Effect: The maximum reduction in blood pressure usually occurs 4 to 6 hours after dosing.
• Duration: The effects of a single dose persist for approximately 24 hours, allowing for once-daily dosing in many patients.
• Tolerance: There is no evidence of the development of tolerance (loss of effect) with long-term use of Enalapril.

| Parameter | Value |

|---|---|

| Bioavailability | ~60% (as Enalapril) |

| Protein Binding | 50% to 60% (as Enalaprilat) |

| Half-life | ~11 hours (effective for accumulation) |

| Tmax | 1 hour (Enalapril); 4 hours (Enalaprilat) |

| Metabolism | Hepatic de-esterification to Enalaprilat |

| Excretion | Renal 94%, Fecal 6% |

• Molecular Formula: C20H28N2O5 • C4H4O4
• Molecular Weight: 492.52 g/mol
• Solubility: Sparingly soluble in water; soluble in ethanol; freely soluble in methanol.
• Structure: It is a derivative of two amino acids, L-alanine and L-proline.

Enalapril is a member of the ACE inhibitor class. It is chemically related to drugs like Lisinopril and Ramipril. Unlike Lisinopril, which is active as administered, Enalapril requires liver metabolism to become active, classifying it as a prodrug. It is distinct from Thiazide diuretics, though it is frequently prescribed alongside them to achieve synergistic blood pressure control.