Quinaretic
Quinaretic Uses, Dosage, Side Effects, Food Interaction and all others data.
Thiazides such as hydrochlorothiazide promote water loss from the body (diuretics). They inhibit Na+/Cl- reabsorption from the distal convoluted tubules in the kidneys. Thiazides also cause loss of potassium and an increase in serum uric acid. Thiazides are often used to treat hypertension, but their hypotensive effects are not necessarily due to their diuretic activity. Thiazides have been shown to prevent hypertension-related morbidity and mortality although the mechanism is not fully understood. Thiazides cause vasodilation by activating calcium-activated potassium channels (large conductance) in vascular smooth muscles and inhibiting various carbonic anhydrases in vascular tissue.
Hydrochlorothiazide prevents the reabsorption of sodium and water from the distal convoluted tubule, allowing for the increased elimination of water in the urine. Hydrochlorothiazide has a wide therapeutic window as dosing is individualized and can range from 25-100mg. Hydrochlorothiazide should be used with caution in patients with reduced kidney or liver function.
Quinapril is the ethyl ester prodrug of the non-sulfhydryl angiotensin converting enzyme inhibitor quinaprilat. It is used to treat hypertension and heart failure. ACE inhibitors are commonly used as a first line therapy in the treatment of hypertension, along with thiazide diuretics or beta blockers.
Quinapril was granted FDA approval on 19 November 1991. A combination tablet with hydrochlorothiazide was also approved on 28 December 1999.
Quinapril is a prodrug of an angiotensin converting enzyme (ACE) inhibitor used in the treatment of hypertension or adjunct in the treatment of heart failure. Quinapril has a wide therapeutic window and a long duration of action as it is given in doses of 10-80mg once daily.
| Trade Name | Quinaretic |
| Generic | Hydrochlorothiazide + Quinapril |
| Weight | 12.5mg + 10mg, 12.5mg + 20mg, 25mg + 20mg, |
| Type | Oral Tablet, Tablets |
| Therapeutic Class | |
| Manufacturer | |
| Available Country | United States |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
Hydrochlorothiazide is used for-
- Edema associated with congestive heart failure, hepatic cirrohosis, various forms of renal dysfunction and corticosteroid and estrogen therapy
- Management of hypertension either as the sole therapeutic agent or to enhance the effectiveness of other antihypertensive drugs in the more severe form of hypertension
- Management of diabetes insipidus
- Management of proximal renal tubular acidosis
- Idiopathic hypercalciuria and calcium nephrolithiasis, osteoporosis and exercise induced hyperkalemia
Quinapril is an ACE inhibitor prodrug used to treat hypertension, congestive heart failure, and slow rate of progression of renal disease.
Quinapril is indicated for the treatment of hypertension and as an adjunct therapy in the treatment of heart failure. Quinapril in combination with hydrochlorothiazide is indicated for the treatment of hypertension.
Quinaretic is also used to associated treatment for these conditions: Acidosis, Renal Tubular, Calcium Nephrolithiasis, Cirrhosis of the Liver, Congestive Heart Failure (CHF), Diabetes Insipidus, Edema, High Blood Pressure (Hypertension), Hypertension,Essential, Hypokalemia caused by diuretics, Nephrotic Syndrome, Premenstrual tension with edema, Sodium retention, Stroke, Prophylaxis of preeclampsiaCongestive Heart Failure (CHF), Diabetic Nephropathy, High Blood Pressure (Hypertension), Left Ventricular Dysfunction
How Quinaretic works
Hydrochlorothiazide is transported from the circulation into epithelial cells of the distal convoluted tubule by the organic anion transporters OAT1, OAT3, and OAT4. From these cells, hydrochlorothiazide is transported to the lumen of the tubule by multidrug resistance associated protein 4 (MRP4).
Normally, sodium is reabsorbed into epithelial cells of the distal convoluted tubule and pumped into the basolateral interstitium by a sodium-potassium ATPase, creating a concentration gradient between the epithelial cell and the distal convoluted tubule that promotes the reabsorption of water.
Hydrochlorothiazide acts on the proximal region of the distal convoluted tubule, inhibiting reabsorption by the sodium-chloride symporter, also known as Solute Carrier Family 12 Member 3 (SLC12A3). Inhibition of SLC12A3 reduces the magnitude of the concentration gradient between the epithelial cell and distal convoluted tubule, reducing the reabsorption of water.
Angiotensin II constricts coronary blood vessels and is positively inotropic, which under normal circumstances, would increase vascular resistance and oxygen consumption. This action can eventually lead to myocyte hypertrophy and vascular smooth muscle cell proliferation. Angiotensin II also stimulates production of plasminogen activator inhibitor-1 (PAI-1), increasing the risk of thrombosis.
Quinaprilat prevents the conversion of angiotensin I to angiotensin II by inhibition of angiotensin converting enzyme, and also reduces the breakdown of bradykinin. Reduced levels of angiotensin II lead to lower levels of PAI-1, reducing the risk of thrombosis, especially after a myocardial infarction.
Dosage
Quinaretic dosage
Adults-
For Edema: The usual adult dosage is 25 to 100 mg daily as a single or divided dose.
For Control of Hypertension: The usual initial dose in adults is 25 mg daily given as a single dose. The dose may be increased to 50 mg daily, given as a single or two divided doses. Doses above 50 mg are often associated with marked reductions in serum potassium. In some patients (especially the elderly) an initial dose of 12.5 mg daily may be sufficient.
Infants and children-
For diuresis and for control of hypertension: The usual pediatric dosage is 1 to 2 mg/kg/day in single or two divided doses, not to exceed 37.5 mg per day in infants up to 2 years of age or 100 mg per day in children 2 to 12 years of age. In infants less than 6 months of age, doses up to 3 mg/kg/day in two divided doses may be required.
Side Effects
Generally, Hydrochlorothiazide is well tolerated. However, a few side effects may occur like weakness, restlessness, dizziness, headache, fever, diarrhea, vomiting, sialadenitis, cramping, constipation, gastric irritation, nausea, anorexia, and hypotension. In rare case hyperglycemia, glycosuria, hyperuricemia and muscle spasm may occur.
Toxicity
The oral LD50 of hydrochlorothiazide is >10g/kg in mice and rats.
Patients experiencing an overdose may present with hypokalemia, hypochloremia, and hyponatremia. Treat patients with symptomatic and supportive treatment including fluids and electrolytes. Vasopressors may be administered to treat hypotension and oxygen may be given for respiratory impairment.
The oral LD50 in rats is 3541mg/kg and in mice is 1739mg/kg.
Patients experiencing an overdose may present with symptoms of severe hypotension. Due to the extensive protein binding of quinapril and the active metabolite quinaprilat, hemodialysis is not expected to remove the drug from circulation. Treat patients with symptomatic and supportive measures, including normal saline infusions to restore normal blood pressure.
Precaution
Thiazides should be used with caution in patients with severe renal disease, impaired hepatic function or progressive liver disease and gout.
Interaction
Alcohol, Barbiturates, or Narcotics: Potentiation of orthostatic hypotension may occur.
Antidiabetic Drugs (oral agents and insulin): Thiazides can impair control of diabetes mellitus by diet and antidiabetic Drugs. Antihypertensive Drugs: Additive effect or potentiation.
Volume of Distribution
The volume of distribution varies widely from one study to another with values of 0.83-4.19L/kg.
The mean volume of distribution of quinaprilat is 13.9L.
Elimination Route
An oral dose of hydrochlorothiazide is 65-75% bioavailable, with a Tmax of 1-5 hours, and a Cmax of 70-490ng/mL following doses of 12.5-100mg. When taken with a meal, bioavailability is 10% lower, Cmax is 20% lower, and Tmax increases from 1.6 to 2.9 hours.
Quinapril if 50-80% bioavailable. Quinapril has a Tmax of 6 while quinaprilat has a Tmax of 2.5h. The Cmax of quinaprilat is highly variable but reaches 1526ng/mL with an AUC of 2443ng*h/mL in healthy males given a 10mg dose. A high fat meal reduces the absorption of quinapril by 25-30%.
Half Life
The plasma half life of hydrochlorothiazide is 5.6-14.8h.
The active metabolite quinaprilat has an elimination half life of 2.3 hours.
Clearance
The renal clearance of hydrochlorothiazide in patients with normal renal function is 285mL/min. Patients with a creatinine clearance of 31-80mL/min have an average hydroxychlorothiazide renal clearance of 75mL/min, and patients with a creatinine clearance of ≤30mL/min have an average hydroxychlorothiazide renal clearance of 17mL/min.
The clearance of quinaprilat is 68mL/min.
Elimination Route
Hydrochlorothiazide is eliminated in the urine as unchanged hydrochlorothiazide.
Quinaprilat is up to 96% eliminated in the urine. The eliminated metabolites PD109488 and PD113413 account for approximately 6% of a dose of quinapril each. A small fraction of the dose recovered in the urine is accounted for by unmetabolized quinapril.
Pregnancy & Breastfeeding use
Pregnancy: Evidence of fetal risk in hydrochlorothiazide therapy is found, but it is indicated if benefits outweigh risks. Thiazides are indicated in pregnancy when edema is due to pathologic causes.\
Lactation: Neonatal side effects have been seen incase of hydrochlorothiazide therapy and therefore it is not recommended.
Contraindication
Hydrochlorothiazide is contraindicated to the patients of anuria and those who are sensitive to hydrochlorothiazide or to other sulfonamide-derived drugs. Therapy is not to be initiated in diabetes mellitus.
Special Warning
Elderly: in some patients specially the elderly an initial dose of 12.5 mg daily may be sufficient.
Children: An initial dose for children has been 1 to 2 mg per kg body-weight in 2 divided doses. Infants under 6 months may need doses upto 3 mg per kg daily.
Acute Overdose
The most common signs and symptoms observed are those caused by electrolyte depletion (hypokalemia, hypochloremia, hyponatremia) and dehydration resulting from excessive diuresis. Rarely, autoimmune hemolytic anemia and other hypersensitivity reactions may complicate the picture.
In the event of over dosage, symptomatic and supportive measures should be employed. Emesis should be induced or gastric lavage performed. Correct dehydration, electrolyte imbalance, hepatic coma and hypotension by established procedures. Hemodialysis can be used successfully to treat severe intoxication.
Storage Condition
Store between 15-30°C. Protect from light, moisture and freezing.
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