Usage
- Medical Conditions: Hydrochlorothiazide + Lisinopril is primarily prescribed for the management of hypertension (high blood pressure). It is used when treatment with individual components (lisinopril or hydrochlorothiazide alone) is insufficient to control blood pressure.
- Pharmacological Classification: This combination drug belongs to two classes:
- Lisinopril: Angiotensin-Converting Enzyme (ACE) inhibitor
- Hydrochlorothiazide: Thiazide diuretic
- Mechanism of Action: Lisinopril works by inhibiting the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. This leads to vasodilation and a decrease in aldosterone secretion, resulting in lower blood pressure. Hydrochlorothiazide increases the excretion of sodium and water by the kidneys, further contributing to blood pressure reduction.
Alternate Names
- No official alternate generic names exist for this fixed-dose combination.
- Brand Names: Zestoretic, Prinzide.
How It Works
- Pharmacodynamics: Lisinopril lowers blood pressure through vasodilation and reduction of aldosterone secretion. Hydrochlorothiazide exerts its diuretic action by inhibiting sodium reabsorption in the distal convoluted tubule of the nephron, leading to increased excretion of sodium and water.
- Pharmacokinetics:
- Absorption: Both drugs are orally absorbed, although lisinopril’s absorption is somewhat variable and not affected by food.
- Metabolism: Lisinopril is not metabolized. Hydrochlorothiazide undergoes minimal hepatic metabolism.
- Elimination: Lisinopril is excreted primarily unchanged in the urine. Hydrochlorothiazide is also eliminated mainly through renal excretion.
- Mode of Action: Lisinopril acts by inhibiting ACE, preventing the formation of angiotensin II. Hydrochlorothiazide inhibits the sodium-chloride cotransporter in the distal convoluted tubule, impeding sodium reabsorption.
- Receptor Binding/Enzyme Inhibition: Lisinopril inhibits ACE. Hydrochlorothiazide inhibits the sodium-chloride cotransporter.
- Elimination Pathways: Primarily renal excretion for both lisinopril and hydrochlorothiazide.
Dosage
Standard Dosage
Adults:
- Initial dose: 10 mg lisinopril/12.5 mg hydrochlorothiazide or 20 mg lisinopril/12.5 mg hydrochlorothiazide orally once daily.
- Dosage adjustments can be made every 2-3 weeks based on blood pressure response.
- Maximum dose: 80 mg lisinopril/50 mg hydrochlorothiazide per day.
Children:
- Not recommended for pediatric use. Safety and efficacy have not been established in children under 18.
Special Cases:
- Elderly Patients: Start at the low end of the dosing range and titrate cautiously. Consider age-related decline in renal function.
- Patients with Renal Impairment:
- Mild to moderate impairment (CrCl > 30 mL/min): No initial dose adjustment. Careful monitoring is recommended.
- Severe impairment (CrCl < 30 mL/min): Not recommended, loop diuretics are preferred.
- Patients with Hepatic Dysfunction: Use with caution. Dose adjustment may be needed.
- Patients with Comorbid Conditions: Close monitoring is required in patients with diabetes, heart failure, or other cardiovascular diseases.
Clinical Use Cases Dosage primarily pertains to chronic hypertension management, and this medication is generally not indicated for acute situations such as intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations like cardiac arrest.
Dosage Adjustments
Dose adjustments may be needed for patients with renal or hepatic dysfunction.
Side Effects
Common Side Effects
- Dizziness, lightheadedness
- Headache
- Cough
- Fatigue
- Diarrhea
- Nausea/vomiting
Rare but Serious Side Effects
- Angioedema (swelling of face, lips, tongue, or throat)
- Hypotension (low blood pressure)
- Renal failure
- Hyperkalemia (high potassium)
- Hyponatremia (low sodium)
Long-Term Effects
- Electrolyte imbalances
- Renal impairment
Adverse Drug Reactions (ADR)
- Angioedema
- Acute renal failure
Contraindications
- Hypersensitivity to lisinopril, hydrochlorothiazide, or sulfonamide-derived drugs.
- History of angioedema related to ACE inhibitor use.
- Hereditary or idiopathic angioedema.
- Anuria (absence of urine production).
- Pregnancy (second and third trimesters).
- Concomitant use with aliskiren in patients with diabetes or moderate to severe renal impairment.
- Concomitant use with sacubitril/valsartan.
Drug Interactions
- Potassium supplements or salt substitutes
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- Lithium
- Aliskiren (especially in patients with diabetes or renal impairment)
- Other antihypertensive medications
- Alcohol
Pregnancy and Breastfeeding
- Pregnancy Safety Category: D (second and third trimesters)
- Fetal risks: ACE inhibitors can cause fetal harm or death, especially during the second and third trimesters.
- Breastfeeding: Hydrochlorothiazide passes into breast milk. Lisinopril’s presence in breast milk is unknown. Use with caution during breastfeeding.
Drug Profile Summary
- Mechanism of Action: ACE inhibitor and thiazide diuretic combination lowering blood pressure.
- Side Effects: Dizziness, headache, cough, fatigue, electrolyte imbalances.
- Contraindications: Hypersensitivity, angioedema history, anuria, pregnancy, aliskiren use with diabetes or renal impairment.
- Drug Interactions: Potassium supplements, NSAIDs, lithium, aliskiren.
- Pregnancy & Breastfeeding: Contraindicated in second and third-trimester pregnancy. Use cautiously during breastfeeding.
- Dosage: Starting dose 10/12.5 mg or 20/12.5 mg once daily; maximum 80/50 mg daily.
- Monitoring Parameters: Blood pressure, renal function, electrolytes (especially potassium and sodium).
Popular Combinations
This medication itself is a combination, and further combining it with other antihypertensives is done cautiously and based on patient-specific needs.
Precautions
- Monitor renal function and electrolytes, especially in patients with pre-existing renal disease, heart failure, or those taking other medications affecting these parameters.
- Be aware of the risk of hypotension, especially during treatment initiation.
- Caution in patients with a history of gout or diabetes.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Hydrochlorothiazide + Lisinopril?
A: Initial dose: 10/12.5 mg or 20/12.5 mg once daily, titrated up to a maximum of 80/50 mg daily as needed based on blood pressure response.
Q2: Can this combination be used in pregnant women?
A: Contraindicated during the second and third trimesters of pregnancy. Use during the first trimester is generally avoided.
Q3: What are the most common side effects?
A: Dizziness, headache, cough, and fatigue.
Q4: Are there any serious adverse effects to watch for?
A: Yes, angioedema (swelling of the face, lips, or throat), hypotension, renal impairment, hyperkalemia, and hyponatremia are rare but serious side effects.
Q5: How does this medication interact with potassium supplements?
A: Hydrochlorothiazide + Lisinopril can increase serum potassium levels, so concomitant use with potassium supplements or salt substitutes can lead to hyperkalemia. Close monitoring of potassium levels is essential.
Q6: What should be done if a patient experiences angioedema?
A: Discontinue the medication immediately and seek emergency medical attention.
Q7: Can patients with renal impairment use this medication?
A: It can be used in patients with mild to moderate renal impairment with careful monitoring but is not recommended in patients with severe renal impairment.
Q8: Is it safe to drink alcohol while taking this medication?
A: Alcohol can exacerbate the hypotensive effects of this medication, so it should be consumed with caution or avoided.
Q9: Should the dose be adjusted for elderly patients?
A: Yes, it’s advisable to start with a lower dose in elderly patients and titrate cautiously, considering age-related decline in renal function.
Q10: How does this medication affect patients with diabetes?
A: Thiazide diuretics can impair glucose tolerance, so blood glucose levels should be monitored closely in patients with diabetes.
