Spironolactone and hydrochlorothiazide
Spironolactone and hydrochlorothiazide 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.
Spironolactone is a specific pharmacologic antagonist of aldosterone, acting primarily through competitive binding of receptors at the aldosterone-dependent sodium-potassium exchange site in the distal convoluted renal tubule. Spironolactone causes increased amounts of sodium and water to be excreted, while potassium is retained. Spironolactone acts both as a diuretic and as an antihypertensive drug by this mechanism. It may be given alone or with other diuretic agents which act more proximally in the renal tubule. Aldosterone interacts with a cytoplasmic mineralocorticoid receptor to enhance the expression of the Na+ K+ ATPase and the Na+ channel involved in a Na+ K+transport in the distal tubule . Spironolactone bind to this mineralcorticoid receptor, blocking the actions of aldosterone on gene expression. Aldosterone is a hormone; its primary function is to retain sodium and excrete potassium in the kidneys.
Originally spironolactone was only studied for its potassium sparing diuretic effect. Spironolactone competitively inhibits mineralocorticoid receptors in the distal convoluted tubule to promote sodium and water excretion and potassium retention.. Inhibition of this receptor leads to increased renin and aldosterone levels.
Spironolactone is structurally similar to progesterone and as a result is associated with progestogenic and antiandrogenic effects.
| Trade Name | Spironolactone and hydrochlorothiazide |
| Generic | Hydrochlorothiazide + Spironolactone |
| Type | Oral |
| 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
Spironolactone is used for Congestive heart failure, Hepatic cirrhosis with ascites and oedema, Nephrotic syndrome, Primary hyperaldosteronism, Essential hypertension, For the treatment of patients with hypokalemia
Spironolactone is a long-acting aldosterone antagonist. Spironolactone is a specific pharmacologic antagonist of aldosterone, acting primarily through competitive binding of receptors at the aldosterone dependent sodium-potassium exchange site in the distal convoluted renal tubule. Spironolactone causes increased amounts of sodium and water to be excreted, while potassium and magnesium is retained.
Spironolactone and hydrochlorothiazide 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 preeclampsiaAcne, Ascites, Congestive Heart Failure (CHF), Edema, High Blood Pressure (Hypertension), Hypokalemia, Idiopathic Hirsutism, Nephrotic Syndrome, Primary Hyperaldosteronism, Secondary hyperaldosteronism, Chronic heart failure with reduced ejection fraction (NYHA Class III), Chronic heart failure with reduced ejection fraction (NYHA Class IV), Idiopathic hyperaldosteronism
How Spironolactone and hydrochlorothiazide 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.
Spironolactone competitively inhibits aldosterone dependant sodium potassium exchange channels in the distal convoluted tubule. This action leads to increased sodium and water excretion, but more potassium retention. The increased excretion of water leads to diuretic and also antihypertensive effects.
Dosage
Spironolactone and hydrochlorothiazide 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.
Edema in adults (congestive heart failure, hepatic cirrhosis, or nephrotic syndrome): An initial daily dosage of 100 mg of Spironolactone administered in either single or divided doses is recommended, but may range from 25 to 200 mg daily. Combined therapy with other diuretics is indicated when more rapid diuresis is desired.
Primary hyperaldosteronism: After the diagnosis of hyperaldosteronism has been established, Spironolactone may be administered in doses of 100 to 400 mg daily in preparation for surgery. For patients who are considered unsuitable for surgery, Spironolactone may be employed for long-term maintenance therapy at the lowest effective dosage determined for the individual patient.
Essential hypertension: For adults, an initial daily dosage of 50 to 100 mg of Spironolactone administered in either single or divided doses is recommended.
Hypokalemia: Spironolactone in a dosage ranging from 25 mg to 100 mg daily is useful in treating a diuretic-induced hypokalemia.
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.
Gynaecomastia may develop in association with the use of Spironolactone. Other adverse reactions are: GI symptoms including cramping and diarrhoea, drowsiness, lethargy, headache, urticaria, mental confusion, impotence, irregular menses or amenorrhoea and post-menopausal bleeding.
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.
Patients experiencing an overdose may present with drowsiness, mental confusion, maculopapular or erythematous rash, nausea, vomiting, dizziness, or diarrhea. Vomiting is generally induced or a gastric lavage is performed. Supportive treatment involves maintining hydration, electrolyte balance, and vital functions.
The oral LD50 in mice, rats, and rabbits is >1g/kg.
Spironolactone should be avoided in pregnancy due to reports of feminization of male fetuses in animal studies. Active metabolites of spironolactone are present in breast milk and levels that are likely inconsequential, though the long term effects have not been studied.
In animal studies, spironolactone slowed follicle development, ovulation, and implantation. Spironolactone increased the incidence of benign adenomas in the testes of male rats, benign uterine endometrial stromal polyps in female rats, and thyroid follicular cell adenomas in both sexes of rats. Spironolactone and canrenone are generally not considered to be mutagenic in tests but canrenone occasionally tests positive for mutagenicity with metabolic activation and spironolactone has occasionally tested inconclusive though slightly positive for mutagenicity.
Precaution
Thiazides should be used with caution in patients with severe renal disease, impaired hepatic function or progressive liver disease and gout.
All patients receiving diuretic therapy should be observed for evidence of fluid or electrolyte imbalance. Hyperkalemia may occur in patients with impaired renal function or excessive potassium intake and can cause cardiac irregularities, which may be fatal.
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.
ACE inhibitors: Concomitant administration of ACE inhibitors with potassium-sparing diuretics has been associated with severe hyperkalemia.
Alcohol, barbiturates, or narcotics: Potentiation of orthostatic hypotension may occur.
Corticosteroids, ACTH: Intensified electrolyte depletion, particularly hypokalemia, may occur.
Lithium: Lithium generally should not be given with diuretics. Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity.
Digoxin: Spironolactone has been shown to increase the half-life of digoxin.
Volume of Distribution
The volume of distribution varies widely from one study to another with values of 0.83-4.19L/kg.
Volume of distribution data is not readily available.
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.
Spironolactone reaches a maximum concentration in 2.6 hours and an active metabolite (canrenone) reaches a maximum concentration in 4.3 hours. When taken with food, the bioavailability of spironolactone increases to 95.4%.
Giving spironolactone with food increases the maximum concentration from 209ng/mL to 301ng/mL. The time to maximum concentration also increases from 2.28 hours to 3.05 hours. The area under the curve varies from 2103ng/mL*hr to 4544ng/mL*hr.
Half Life
The plasma half life of hydrochlorothiazide is 5.6-14.8h.
1.4 hours.
Canrenone has a half life of 16.5 hours, 7-α-thiomethylspirolactone has a half life of 13.8 hours, and 6-ß-hydroxy-7-α-thiomethylspirolactone has a half life of 15 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.
Clearance data is not readily available.
Elimination Route
Hydrochlorothiazide is eliminated in the urine as unchanged hydrochlorothiazide.
Metabolites of spironolactone are excreted 42-56% in urine, and 14.2-14.6% in the feces. No unmetabolized spironolactone is present in the urine.
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.
Pregnancy: Spironolactone should not be used during pregnancy
Lactation: Canrenone, an active metabolite of Spironolactone, appears in breast milk. If use of the drug is deemed essential an alternative method of infant feeding should be instituted.
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.
Spironolactone is contraindicated in patients with acute renal insufficiency, significant impairment of renal function, anuria, hyperkalaemia or sensitivity to Spironolactone.
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.
Symptoms of overdosage include drowsiness, mental confusion, dizziness, diarrhea and vomiting etc. Patients should induce vomiting or evacuate the stomach by lavage during Spironolactone overdoasge.
Storage Condition
Store between 15-30°C. Protect from light, moisture and freezing.
Store in a cool and dry place protected from light. Keep out of reach of children.
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