Zestril 5 mg Tablets

Brand Name

This medication is marketed under the trade name Zestril, widely acknowledged among healthcare practitioners for its effectiveness in managing cardiovascular conditions.

International Nonproprietary Name (INN)

The active ingredient is universally identified as lisinopril, ensuring its consistent recognition across global medical standards.

Form of Release

The drug is available as tablets, designed for oral administration and offered in various strengths to accommodate diverse patient requirements. These tablets are crafted for ease of use and maintain stability under typical storage conditions.

Composition

Lisinopril serves as the primary active component, engineered to influence blood pressure and cardiac function. Accompanying this are auxiliary substances such as mannitol, calcium phosphate, magnesium stearate, and corn starch, which provide structural support and facilitate disintegration upon ingestion. Some formulations may include colorants like iron oxides for visual distinction. Each element is purposefully integrated to enhance the therapeutic action of lisinopril while ensuring its reliability and consistency.

Pharmacologic Properties

Pharmacodynamics

This medication functions as an angiotensin-converting enzyme (ACE) inhibitor, targeting the renin-angiotensin-aldosterone system to exert its effects. By preventing the conversion of angiotensin I to angiotensin II, it inhibits vasoconstriction and aldosterone release, leading to relaxation of blood vessels and reduced fluid retention. This action decreases peripheral resistance and blood pressure while alleviating cardiac preload and afterload. It also preserves bradykinin levels, promoting vasodilation and potential vascular protection. Effects typically begin within one hour, peaking at six to eight hours, with benefits sustained over 24 hours, supporting once-daily dosing. This mechanism enhances its utility in cardiovascular management and organ preservation.

Pharmacokinetics

Following oral intake, the drug absorbs from the gastrointestinal tract with a bioavailability of about 25% to 50%, unaffected by food. Peak plasma concentrations occur within six to eight hours. Lisinopril does not bind significantly to plasma proteins and distributes widely, reaching tissues like the kidneys and heart. It undergoes no hepatic metabolism, being excreted unchanged entirely through urine via glomerular filtration. The half-life ranges from 12 to 24 hours, prolonged in renal impairment due to reduced clearance, requiring careful oversight. This straightforward pharmacokinetic profile ensures consistent activity across varied patient conditions.

Indications for Use

This medication is prescribed for conditions involving elevated blood pressure or cardiac strain. It is primarily indicated for hypertension, effectively reducing pressure to lower cardiovascular risk, suitable for mild to severe cases. It also manages heart failure by reducing cardiac workload and improving outcomes, particularly in patients with reduced ejection fraction. In post-myocardial infarction settings, it supports left ventricular dysfunction, delaying progression to overt heart failure and enhancing survival. Its broad applicability makes it a cornerstone in both acute and chronic cardiovascular therapeutic strategies.

Contraindications

Specific conditions limit the use of this drug to ensure patient safety. Hypersensitivity to lisinopril, other ACE inhibitors, or tablet components prohibits its administration, as reactions could range from rashes to anaphylaxis. A history of angioedema, whether idiopathic or linked to prior ACE inhibitor use, excludes it due to recurrence risks. Severe renal artery stenosis, bilateral or in a solitary kidney, contraindicates it, as reduced renal perfusion could impair kidney function. It is avoided in pregnancy beyond the first trimester due to potential fetal harm, including renal damage. Significant hyperkalemia or uncorrected electrolyte imbalances also preclude its use to avoid further disruption.

Method of Administration and Dosage

How to Take

Tablets are taken orally, with or without food, offering flexibility in timing, though a regular schedule supports stable blood levels. Swallowing them whole with water ensures effective delivery to the digestive system. Consistency in daily timing enhances therapeutic reliability.

Dosage for Adults and Children

For adults with hypertension, treatment typically starts at 10 mg once daily, adjustable to 20 mg or 40 mg daily based on response, with a maximum of 80 mg in resistant cases. In heart failure, 2.5 mg to 5 mg once daily is common, increasing to 20 mg to 40 mg daily as tolerated, guided by clinical stability. Pediatric dosing for hypertension in children aged 6 and older begins at 0.07 mg per kilogram once daily, up to 5 mg, with a maximum of 0.61 mg per kilogram or 40 mg, tailored under specialist supervision. Blood pressure monitoring ensures dosing balances efficacy and safety across age groups.

Dose Adjustment in Specific Conditions

Renal impairment requires lower doses; if creatinine clearance is 10 to 30 mL/min, start at 5 mg daily, reducing to 2.5 mg if below 10 mL/min, with potassium oversight. Hepatic dysfunction typically needs no adjustment, as it is not metabolized, though severe cases warrant caution. Older adults or those with reduced renal reserve may initiate at 2.5 mg daily to minimize hypotension risks. Frequent assessments tailor dosing to each patient’s physiological needs, particularly in compromised states.

Side Effects

This medication may provoke various unintended responses, though most are manageable. A persistent dry cough, tied to bradykinin accumulation, is frequent, often resolving upon discontinuation. Dizziness or lightheadedness might occur, typically linked to blood pressure reductions, especially early in use. Fatigue, headache, or nausea can affect some individuals, usually subsiding with time. Hyperkalemia may arise, causing muscle weakness or irregular heartbeats in at-risk patients. Rarely, severe reactions like angioedema—swelling of the face or throat—or significant kidney impairment emerge, requiring immediate medical attention. Patient reports and periodic lab checks help manage these effects effectively.

Overdose

Symptoms of Overdose

Excessive intake can lead to profound hypotension, resulting in dizziness, fainting, or circulatory collapse due to excessive vasodilation. Bradycardia might develop, though tachycardia could occur as compensation. Electrolyte imbalances, particularly hyperkalemia, may cause muscle cramps or arrhythmias, posing risks if uncorrected. Symptoms typically appear within hours and escalate without intervention, reflecting the drug’s strong systemic influence.

First Aid Measures

In an overdose scenario, discontinue administration immediately and seek urgent medical assistance. If ingestion is recent, activated charcoal may curb absorption, applied under professional supervision. Intravenous fluids or vasopressors like norepinephrine address hypotension, while monitoring corrects potassium levels and stabilizes heart rhythm. Supportive care, including positioning the patient flat, assists until medical support arrives. Focus is on restoring circulatory balance rapidly.

Drug Interactions

Effects on Other Medications

This drug can alter the effects of other medications when used concurrently. It may amplify the pressure-lowering action of other antihypertensives, requiring dose tweaks to avoid excessive drops. Potassium-sparing diuretics or supplements increase hyperkalemia risks, needing electrolyte oversight. Nonsteroidal anti-inflammatory drugs might reduce its efficacy and strain kidneys, particularly with prolonged use. Lithium levels could rise due to decreased clearance, necessitating plasma checks. Adjustments minimize these interaction risks effectively.

Compatibility with Alcohol and Food

Alcohol consumption may intensify hypotension, increasing dizziness risks, so moderation is advised. Food does not affect absorption, allowing flexible timing, with no specific dietary restrictions beyond avoiding excessive potassium intake to prevent imbalance. A balanced diet supports overall efficacy.

Special Precautions

Use During Pregnancy and Breastfeeding

This medication is contraindicated in pregnancy beyond the first trimester, as it may cause fetal renal damage or death, based on extensive evidence. It passes into breast milk in small amounts, potentially affecting infant kidney function, so nursing mothers should consult their physician, possibly opting for alternatives to minimize exposure.

Impact on Driving and Machinery Operation

Dizziness or fatigue, especially at initiation or dose changes, may impair driving or machinery operation. Patients should evaluate their tolerance before such activities, ensuring safety for themselves and others.

Considerations for Elderly and Pediatric Populations

Older adults may require lower initial doses due to reduced renal clearance, with monitoring for hypotension or electrolyte shifts. In children aged 6 and up, its use is tailored for hypertension, with weight-based doses adjusted cautiously under specialist guidance to avoid developmental impact. Personalized care optimizes safety and efficacy across these groups.