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2D Structure
Also known as: 52-01-7, Aldactone, Spirolactone, Verospirone, Verospiron, Euteberol
Molecular Formula
C24H32O4S
Molecular Weight
416.6  g/mol
InChI Key
LXMSZDCAJNLERA-ZHYRCANASA-N
FDA UNII
27O7W4T232

A potassium sparing diuretic that acts by antagonism of aldosterone in the distal renal tubules. It is used mainly in the treatment of refractory edema in patients with congestive heart failure, nephrotic syndrome, or hepatic cirrhosis. Its effects on the endocrine system are utilized in the treatments of hirsutism and acne but they can lead to adverse effects. (From Martindale, The Extra Pharmacopoeia, 30th ed, p827)
Spironolactone is an Aldosterone Antagonist. The mechanism of action of spironolactone is as an Aldosterone Antagonist.
1 2D Structure

2D Structure

2 Identification
2.1 Computed Descriptors
2.1.1 IUPAC Name
S-[(7R,8R,9S,10R,13S,14S,17R)-10,13-dimethyl-3,5'-dioxospiro[2,6,7,8,9,11,12,14,15,16-decahydro-1H-cyclopenta[a]phenanthrene-17,2'-oxolane]-7-yl] ethanethioate
2.1.2 InChI
InChI=1S/C24H32O4S/c1-14(25)29-19-13-15-12-16(26)4-8-22(15,2)17-5-9-23(3)18(21(17)19)6-10-24(23)11-7-20(27)28-24/h12,17-19,21H,4-11,13H2,1-3H3/t17-,18-,19+,21+,22-,23-,24+/m0/s1
2.1.3 InChI Key
LXMSZDCAJNLERA-ZHYRCANASA-N
2.1.4 Canonical SMILES
CC(=O)SC1CC2=CC(=O)CCC2(C3C1C4CCC5(C4(CC3)C)CCC(=O)O5)C
2.1.5 Isomeric SMILES
CC(=O)S[C@@H]1CC2=CC(=O)CC[C@@]2([C@@H]3[C@@H]1[C@@H]4CC[C@]5([C@]4(CC3)C)CCC(=O)O5)C
2.2 Other Identifiers
2.2.1 UNII
27O7W4T232
2.3 Synonyms
2.3.1 MeSH Synonyms

1. Aldactone

2. Aldactone A

3. Aquareduct

4. Ct, Spiro Von

5. Duraspiron

6. Espironolactona Alter

7. Espironolactona Mundogen

8. Flumach

9. Frumikal

10. Jenaspiron

11. Novo Spiroton

12. Novo-spiroton

13. Novospiroton

14. Practon

15. Sc 9420

16. Sc-9420

17. Sc9420

18. Spiractin

19. Spiro L.u.t.

20. Spiro Von Ct

21. Spirobeta

22. Spirogamma

23. Spirolactone

24. Spirolang

25. Spirono Isis

26. Spirono-isis

27. Spironone

28. Spirospare

29. Veroshpiron

30. Verospiron

31. Verospirone

32. Von Ct, Spiro

2.3.2 Depositor-Supplied Synonyms

1. 52-01-7

2. Aldactone

3. Spirolactone

4. Verospirone

5. Verospiron

6. Euteberol

7. Spirolang

8. Spiroctan

9. Acelat

10. Aldactone A

11. Spironocompren

12. Melarcon

13. Spiresis

14. Spiridon

15. Uractone

16. Urusonin

17. Alderon

18. Spirone

19. Xenalon

20. Dira

21. Spiro-tablinen

22. Spironolactone A

23. Spironolattone

24. Aquareduct

25. Spironolactonum

26. Aldopur

27. Espironolactona

28. Abbolactone

29. Aldace

30. Almatol

31. Deverol

32. Altex

33. Berlactone

34. Sc 9420

35. Sc-9420

36. Spironolactone Ceva

37. Nsc-150399

38. Chembl1393

39. Chebi:9241

40. Spiro(17h-cyclopenta(a)phenauthrene-17,2'-(3'h)-furan)

41. Sc9420

42. Spironolattone [dcit]

43. 27o7w4t232

44. S-[(7r,8r,9s,10r,13s,14s,17r)-10,13-dimethyl-3,5'-dioxospiro[2,6,7,8,9,11,12,14,15,16-decahydro-1h-cyclopenta[a]phenanthrene-17,2'-oxolane]-7-yl] Ethanethioate

45. Aldactide

46. Spironolactonum [inn-latin]

47. Espironolactona [inn-spanish]

48. Dsstox_cid_14186

49. Dsstox_rid_79120

50. Dsstox_gsid_34186

51. Sc 15983

52. (1's,2r,2'r,9'r,10'r,11's,15's)-9'-(acetylsulfanyl)-2',15'-dimethylspiro[oxolane-2,14'-tetracyclo[8.7.0.0^{2,7}.0^{11,15}]heptadecan]-6'-ene-5,5'-dione

53. 17-hydroxy-7-alpha-mercapto-3-oxo-17-alpha-pregn-4-ene-21-carboxylic Acid-gamma-lactone-7-acetate

54. S-[(7r,8r,9s,10r,13s,14s,17r)-10,13-dimethyl-3,5'-dioxo-1,2,3,4',5',6,7,8,9,10,11,12,13,14,15,16-hexadecahydro-3'h-spiro[cyclopenta[a]phenanthrene-17,2'-furan]-7-yl] Ethanethioate

55. Spiro[17h-cyclopenta[a]phenauthrene-17,2'-(3'h)-furan]

56. Diatense

57. Aldactone (tn)

58. Smr000471892

59. Hsdb 3184

60. Einecs 200-133-6

61. Mfcd00082250

62. Nsc 150399

63. Brn 0057767

64. Spirotone

65. Spiranolactone

66. Carospir

67. Unii-27o7w4t232

68. 2oax

69. 3vhu

70. Cas-52-01-7

71. Ncgc00015948-02

72. 3-(3-keto-7.alpha.-acetylthio-17.beta.-hydroxy-4-androsten-17.alpha.-yl)propionic Acid Lactone

73. 7-.alpha.-(acetylthio)-17-.alpha.-hydroxy-3-oxopregn-4-ene-21-carboxylic Acid, .gamma.-lactone

74. 7-alpha-acetylthio-3-oxo-17-alpha-pregn-4-ene-21,17-beta-carbolactone

75. S-((7r,8r,9s,10r,13s,14s,17r)-10,13-dimethyl-3,5'-dioxo-1,2,3,4',5',6,7,8,9,10,11,12,13,14,15,16-hexadecahydro-3'h-spiro[cyclopenta[a]phenanthrene-17,2'-furan]-7-yl) Ethanethioate

76. Spironolactone [usp:inn:ban:jan]

77. Pregn-4-ene-21-carboxylic Acid, 7-(acetylthio)-17-hydroxy-3-oxo-, Gamma-lactone, (7alpha,17alpha)-

78. Prestwick0_000128

79. Prestwick1_000128

80. Prestwick2_000128

81. Prestwick3_000128

82. Spironolactone [mi]

83. 17-hydroxy-7alpha-mercapto-3-oxo-17alpha-pregn-4-ene-21-carboxylic Acid, Gamma-lactone Acetate

84. 3'-(3-oxo-7-alpha-acetylthio-17-beta-hydroxyandrost-4-en-17-beta-yl)propionic Acid Lactone

85. 3-(3-keto-7-alpha-acetylthio-17-beta-hydroxy-4-androsten-17-alpha-yl)propionic Acid Lactone

86. Spironolactone [inn]

87. Spironolactone [jan]

88. Bidd:pxr0071

89. Schembl20939

90. Bspbio_000176

91. Spironolactone [hsdb]

92. Spironolactone [iarc]

93. Spironolactone [inci]

94. 17alpha-pregn-4-ene-21-carboxylic Acid, 17-hydroxy-7alpha-mercapto-3-oxo-, Gamma-lactone, Acetate

95. 4-18-00-01601 (beilstein Handbook Reference)

96. Mls001074672

97. Mls001333253

98. Mls001333254

99. Mls002153245

100. Mls002207058

101. Mls002548846

102. Spironolactone [vandf]

103. Spbio_002115

104. Spironolactone [mart.]

105. Bpbio1_000194

106. Gtpl2875

107. Spironolactone [usp-rs]

108. Spironolactone [who-dd]

109. Spironolactone [who-ip]

110. Dtxsid6034186

111. Spironolactone (jp17/usp/inn)

112. Hms1568i18

113. Hms2090n21

114. Hms2095i18

115. Hms2236e06

116. Hms3259g11

117. Hms3712i18

118. Act02596

119. Amy40521

120. Hy-b0561

121. Spironolactone, 97.0-103.0%

122. Zinc3861599

123. Spironolactone [orange Book]

124. Tox21_113047

125. Tox21_302154

126. 7alpha-(acetylsulfanyl)-3-oxo-17alpha-pregn-4-ene-21,17-carbolactone

127. Bdbm50228080

128. Nsc150399

129. S4054

130. Spironolactone [ep Monograph]

131. Spironolactone [usp Monograph]

132. Akos015896401

133. Spironolactonum [who-ip Latin]

134. Ac-4214

135. Ccg-220128

136. Db00421

137. Ks-5234

138. Nc00482

139. 7-alpha-(acetylthio)-17-alpha-hydroxy-3-oxopregn-4-ene-21-carboxylic Acid, Gamma-lactone

140. Cardalis Component Spironolactone

141. Spironolactone Component Cardalis

142. Ncgc00164397-01

143. Ncgc00164397-02

144. Ncgc00164397-03

145. Ncgc00164397-05

146. Ncgc00255229-01

147. 17-alpha-pregn-4-ene-21-carboxylic Acid, 17-hydroxy-7-alpha-mercapto-3-oxo-, Gamma-lactone Acetate

148. Bs166385

149. Cpd000471892

150. Spironolactone 1.0 Mg/ml In Acetonitrile

151. Aldactazide Component Spironolactone

152. Spironolactone [ema Epar Veterinary]

153. Ab00513806

154. S0260

155. Spironolactone Component Of Aldactazide

156. C07310

157. C75438

158. D00443

159. Ab01275520-01

160. Ab01275520_02

161. 082s250

162. Q422188

163. Sr-01000765419

164. Sr-05000000452

165. Q-201737

166. Sr-01000765419-2

167. Sr-05000000452-2

168. Brd-k90027355-001-03-4

169. Brd-k90027355-001-19-0

170. Z1551900341

171. Spironolactone, European Pharmacopoeia (ep) Reference Standard

172. Wln: L E5 B666 Fx Ov Mutj A1 E1 Ksv1 F-& Ct5voxtj

173. 17.alpha.-pregn-4-ene-21-carboxylic Acid, .gamma.-lactone Acetate

174. Spironolactone, United States Pharmacopeia (usp) Reference Standard

175. 17.alpha.-pregn-4-ene-21-carboxylic Acid, .gamma.-lactone, Acetate

176. Pregn-4-ene-21-carboxylic Acid, .gamma.-lactone, (7.alpha.,17.alpha.)-

177. (7?,17?)-7-(acetylthio)-17-hydroxy-3-oxopregn-4-ene-21-carboxylic Acid ?-lactone

178. Spironolactone For System Suitability, European Pharmacopoeia (ep) Reference Standard

179. 17-hydroxy-7.alpha.-mercapto-3-oxo-17.alpha.-pregn-4-ene-21-carboxylic Acid, .gamma.-lactone Acetate

180. 17-hydroxy-7alpha-mercapto-3-oxo-17alpha-pregn-4-ene-21- Carboxylic Acid; Gamma-lactone Acetate

181. 2'',15''-dimethyl-5,5''-dioxo-(9''r)-spiro[tetrahydrofuran-2,14''-tetracyclo[8.7.0.02,7.011,15]heptadec-6''-ene]-9-yl Ethanethioate

182. 2'',15''-dimethyl-5,5''-dioxospiro[tetrahydrofuran-2,14''-tetracyclo[8.7.0.02,7.011,15]heptadec-6''-ene]-9-yl Ethanethioate

183. 2'',15''-dimethyl-5,5''-dioxospiro[tetrahydrofuran-2,14''-tetracyclo[8.7.0.02,7.011,15]heptadec-6''-ene]-9-yl Ethanethioate(spiranolactone)

184. Pregn-4-ene-21-carboxylic Acid, 7-(acetylthio)-17-hydroxy-3-oxo-,.gamma.-lactone, (7.alpha.,17.alpha.)-

185. S-(2''r,7r,8r,9s,10r,13s,14s)-10,13-dimethyl-3,5''-dioxo-1,2,3,4'',5'',6,7,8,9,10,11,12,13,14,15,16-hexadecahydro-3''h-spiro[cyclopenta[a]phenanthrene-17,2''-furan]-7-yl Ethanethioate

2.4 Create Date
2005-03-26
3 Chemical and Physical Properties
Molecular Weight 416.6 g/mol
Molecular Formula C24H32O4S
XLogP32.9
Hydrogen Bond Donor Count0
Hydrogen Bond Acceptor Count5
Rotatable Bond Count2
Exact Mass416.20213067 g/mol
Monoisotopic Mass416.20213067 g/mol
Topological Polar Surface Area85.7 Ų
Heavy Atom Count29
Formal Charge0
Complexity818
Isotope Atom Count0
Defined Atom Stereocenter Count7
Undefined Atom Stereocenter Count0
Defined Bond Stereocenter Count0
Undefined Bond Stereocenter Count0
Covalently Bonded Unit Count1
4 Drug and Medication Information
4.1 Drug Information
1 of 6  
Drug NameAldactazide
PubMed HealthSpironolactone/Hydrochlorothiazide (By mouth)
Drug ClassesDiuretic, Potassium Sparing/Thiazide Combination
Active IngredientHydrochlorothiazide; spironolactone
Dosage FormTablet
RouteOral
Strength25mg; 50mg
Market StatusPrescription
CompanyGd Searle

2 of 6  
Drug NameAldactone
PubMed HealthSpironolactone (By mouth)
Drug ClassesAntiandrogen, Cardiovascular Agent
Drug LabelALDACTONE oral tablets contain 25 mg, 50 mg, or 100 mg of the aldosterone antagonist spironolactone, 17-hydroxy-7-mercapto-3-oxo-17-pregn-4-ene-21-carboxylic acid -lactone acetate, which has the following structural formula:Spironolactone is pr...
Active IngredientSpironolactone
Dosage FormTablet
RouteOral
Strength100mg; 25mg; 50mg
Market StatusPrescription
CompanyGd Searle

3 of 6  
Drug NameSpironolactone
PubMed HealthSpironolactone (By mouth)
Drug ClassesAntiandrogen, Cardiovascular Agent
Drug LabelSpironolactone Tablets, USP contain 25 mg, 50 mg, or 100 mg of the aldosterone antagonist spironolactone, 17-hydroxy-7acidacetate, which has the following structural formula:Spironolactone is practically insoluble in water, soluble in alcohol, and fr...
Active IngredientSpironolactone
Dosage FormTablet
RouteOral
Strength25mg; 100mg; 50mg
Market StatusPrescription
CompanyAmneal Pharms; Sandoz; Orion Corp Orion; Actavis Elizabeth; Jubilant Generics; Mutual Pharm; Vintage; Mylan

4 of 6  
Drug NameAldactazide
PubMed HealthSpironolactone/Hydrochlorothiazide (By mouth)
Drug ClassesDiuretic, Potassium Sparing/Thiazide Combination
Active IngredientHydrochlorothiazide; spironolactone
Dosage FormTablet
RouteOral
Strength25mg; 50mg
Market StatusPrescription
CompanyGd Searle

5 of 6  
Drug NameAldactone
PubMed HealthSpironolactone (By mouth)
Drug ClassesAntiandrogen, Cardiovascular Agent
Drug LabelALDACTONE oral tablets contain 25 mg, 50 mg, or 100 mg of the aldosterone antagonist spironolactone, 17-hydroxy-7-mercapto-3-oxo-17-pregn-4-ene-21-carboxylic acid -lactone acetate, which has the following structural formula:Spironolactone is pr...
Active IngredientSpironolactone
Dosage FormTablet
RouteOral
Strength100mg; 25mg; 50mg
Market StatusPrescription
CompanyGd Searle

6 of 6  
Drug NameSpironolactone
PubMed HealthSpironolactone (By mouth)
Drug ClassesAntiandrogen, Cardiovascular Agent
Drug LabelSpironolactone Tablets, USP contain 25 mg, 50 mg, or 100 mg of the aldosterone antagonist spironolactone, 17-hydroxy-7acidacetate, which has the following structural formula:Spironolactone is practically insoluble in water, soluble in alcohol, and fr...
Active IngredientSpironolactone
Dosage FormTablet
RouteOral
Strength25mg; 100mg; 50mg
Market StatusPrescription
CompanyAmneal Pharms; Sandoz; Orion Corp Orion; Actavis Elizabeth; Jubilant Generics; Mutual Pharm; Vintage; Mylan

4.2 Therapeutic Uses

Aldosterone Antagonists; Diuretics

National Library of Medicine's Medical Subject Headings online file (MeSH, 1999)


/EXPL THER:/ Aldosterone is important in the pathophysiology of heart failure. In a doubleblind study, we enrolled 1663 patients who had severe heart failure and a left ventricular ejection fraction of no more than 35 percent and who were being treated with an angiotensin-converting-enzyme inhibitor, a loop diuretic, and in most cases digoxin. A total of 822 patients were randomly assigned to receive 25 mg of spironolactone daily, and 841 to receive placebo. The primary end point was death from all causes. The trial was discontinued early, after a mean follow-up period of 24 months, because an interim analysis determined that spironolactone was efficacious. There were 386 deaths in the placebo group (46 percent) and 284 in the spironolactone group (35 percent; relative risk of death, 0.70; 95 percent confidence interval, 0.60 to 0.82; P<0.001). This 30 percent reduction in the risk of death among patients in the spironolactone group was attributed to a lower risk of both death from progressive heart failure and sudden death from cardiac causes. The frequency of hospitalization for worsening heart failure was 35 percent lower in the spironolactone group than in the placebo group (relative risk of hospitalization, 0.65; 95 percent confidence interval, 0.54 to 0.77; P<0.001). In addition, patients who received spironolactone had a significant improvement in the symptoms of heart failure, as assessed on the basis of the New York Heart Association functional class (P<0.001). Gynecomastia or breast pain was reported in 10 percent of men who were treated with spironolactone, as compared with 1 percent of men in the placebo group (P<0.001). The incidence of serious hyperkalemia was minimal in both groups of patients.

PMID:10471456 Pitt B et al; N Engl J Med 341 (10): 709-17 (1999)


MEDICATION (VET): Spironolactone can be used with furosemide to control ascites.

Kahn, C.M. (Ed.); The Merck Veterinary Manual 9th ed. Merck & Co. Whitehouse Station, NJ. 2005, p. 380


MEDICATION (VET): Spironolactone is used most frequently and is a competitive antagonist of aldosterone. Aldosterone is elevated in animals with congestive heart failure in which the renin-angiotensin system is activated in response to hyponatremia, hyperkalemia, and reductions in blood pressure or cardiac output. Aldosterone is responsible for increasing sodium and chloride reabsorption and potassium and calcium excretion from renal tubules. Spironolactone competes with aldosterone at its receptor site, causing a mild diuresis and potassium retention.

Kahn, C.M. (Ed.); The Merck Veterinary Manual 9th ed. Merck & Co. Whitehouse Station, NJ. 2005, p. 2046


For more Therapeutic Uses (Complete) data for SPIRONOLACTONE (12 total), please visit the HSDB record page.


4.3 Drug Warning

Spironolactone is an aldosterone antagonist that acts on the mineralocorticoid receptor. It is a potassium-sparing diuretic, and hyperkalemia is the most common and potentially serious complication of therapy. Impaired kidney function appears to increase this risk, as does supplementation with potassium chloride. Excessive diuresis can also lead to dehydration and hyponatraemia. A number of endocrine effects have also been reported, the most common of which is gynaecomastia, with a dose-related incidence of 7-52%. This side-effect is reversible and disappears upon discontinuation of therapy. Other endocrine effects include loss of sexual potency in men and menstrual irregularity, amenorrhea, breast engorgement and chloasma in women. These effects are probably due to interaction of spironolactone with the androgen receptor.

IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V79 327 (2001)


There are a few isolated case reports of idiosyncratic drug reactions, including one case of hepatitis and several cases of agranulocytosis. Approximately 10 cases have been reported of allergic contact dermatitis after topical application of spironolactone for various dermal indications involving its antiandrogen activity.

IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V79 327 (2001)


Maternal Medication usually Compatible with Breast-Feeding: Spironolactone: Reported Sign or Symptom in Infant or Effect on Lactation: None. /From Table 6/

Report of the American Academy of Pediatrics Committee on Drugs in Pediatrics 93 (1): 142 (1994)


POTENTIAL ADVERSE EFFECTS ON FETUS: May cross placenta. No controlled studies performed, but no known teratogenic effects. POTENTIAL SIDE EFFECTS ON BREAST-FED INFANT: Active metabolite (canrenone) excreted in breast milk. FDA Category: C (C = Studies in laboratory animals have revealed adverse effects on the fetus (teratogenic, embryocidal, etc.) but there are no controlled studies in pregnant women. The benefits from use of the drug in pregnant women may be acceptable despite its potential risks, or there are no laboratory animal studies or adequate studies in pregnant women.) /From table II/

PMID:2195076 Stockton DL, Paller AS; J Am Acad Dermatol 23 (1):87-103 (1990)


For more Drug Warnings (Complete) data for SPIRONOLACTONE (17 total), please visit the HSDB record page.


4.4 Drug Indication

Spironolactone is indicated for the treatment of New York Heart Association Class III-IV heart failure, management of edema in cirrhotic adults not responsive to fluid and sodium restrictions, primary hyperaldosteronism short-term preoperatively, primary hyperaldosteronism long-term in patients with aldosterone producing adrenal adenomas that are not candidates for surgery or patients with bilarteral micro/macronodular adrenal hyperplasia, as an add-on therapy in hypertension, and in nephrotic syndrome when treatment of the disease as well as fluid and sodium restriction with other diuretics is inadequate. Spironolactone has antiandrogenic activity which leads to many of its off label uses. Spironolactone is used off label in the treatment of hirsutism, female pattern hair loss, and adult acne vulgaris. Spironolactone is also frequently used for its antiandrogenic effects in transgender female patients due to its low cost and reducing male-pattern hair growth.


FDA Label


For use in combination with standard therapy (including diuretic support, where necessary) for the treatment of congestive heart failure caused by valvular regurgitation in dogs.


5 Pharmacology and Biochemistry
5.1 Pharmacology

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.


5.2 MeSH Pharmacological Classification

Mineralocorticoid Receptor Antagonists

Drugs that bind to and block the activation of MINERALOCORTICOID RECEPTORS by MINERALOCORTICOIDS such as ALDOSTERONE. (See all compounds classified as Mineralocorticoid Receptor Antagonists.)


Diuretics

Agents that promote the excretion of urine through their effects on kidney function. (See all compounds classified as Diuretics.)


5.3 FDA Pharmacological Classification
5.3.1 Active Moiety
SPIRONOLACTONE
5.3.2 FDA UNII
27O7W4T232
5.3.3 Pharmacological Classes
Aldosterone Antagonists [MoA]; Aldosterone Antagonist [EPC]
5.4 ATC Code

QC03DA01


C03DA01

S76 | LUXPHARMA | Pharmaceuticals Marketed in Luxembourg | Pharmaceuticals marketed in Luxembourg, as published by d'Gesondheetskeess (CNS, la caisse nationale de sante, www.cns.lu), mapped by name to structures using CompTox by R. Singh et al. (in prep.). List downloaded from https://cns.public.lu/en/legislations/textes-coordonnes/liste-med-comm.html. Dataset DOI:10.5281/zenodo.4587355


C - Cardiovascular system

C03 - Diuretics

C03D - Aldosterone antagonists and other potassium-sparing agents

C03DA - Aldosterone antagonists

C03DA01 - Spironolactone


5.5 Absorption, Distribution and Excretion

Absorption

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.


Route of Elimination

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.


Volume of Distribution

Volume of distribution data is not readily available.


Clearance

Clearance data is not readily available.


At the time spironolactone was introduced for clinical use, its bioavailability was inadequate, and this was improved by preparing the drug in finely powdered or micronized form. The absolute bioavailability was indirectly estimated at approximately 73%, which was enhanced in the presence of food. Nearly all absorbed spironolactone (> 90 %) is bound to plasma proteins and, with repeated dosing, a steady state is achieved within 8 days. After oral intake of a 100-mg dose, the plasma half-time of spironolactone was 1-2 h, the time to maximum plasma concentration was 2-3.2 hr, the maximum blood concentration was 92-148 ng/mL, the area under the concentration--time (0-24 hr) curve was 1430-1541 ng/mL per hr and the elimination half-time was 18-20 hr.

IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V79 325 (2001)


The disposition of (14)C spironolactone was studied in male rats, female dogs and female monkeys after intravenous or oral administration of 5 mg/kg bw. Gastrointestinal absorption was estimated to be 82% in rats, 62% in dogs and 103% in monkeys. Spironolactone was extensively metabolized in all three species, and the metabolites were excreted primarily in the urine and feces. The amount of radiolabel excreted in urine or feces of all three species was similar after intravenous and after oral dosing. In monkeys, as in humans, the amounts excreted in urine and feces were about equal, while fecal excretion predominated in rats and dogs as a result of biliary excretion. After the oral dose, the percentage of urinary excretion was 4.7% in rats, 18% in dogs and 46% in monkeys. The high excretion of radiolabel in the feces of rats (90%) after intravenous administration shows the importance of biliary excretion for that species. Species differences were also noted in the biotransformation of spironolactone. ...

IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V79 326 (2001)


Absorption of spironolactone from the GI tract depends on the formulation in which it is administered. Currently available formulations of spironolactone are well absorbed from the GI tract and bioavailability of the drug exceeds 90% when compared to an optimally absorbed spironolactone solution in polyethylene glycol 400. Following a single oral dose of spironolactone, peak serum concentrations of the drug occur within 1-2 hours, and peak serum concentrations of its principal metabolites are attained within 2-4 hours. When spironolactone is administered concomitantly with food, peak serum concentrations and areas under the serum concentration-time curves (AUCs) of the drug and, to a lesser degree, its principal metabolites are increased substantially compared with the fasting state...

McEvoy, G.K. (ed.). American Hospital Formulary Service. AHFS Drug Information. American Society of Health-System Pharmacists, Bethesda, MD. 2007., p. 1983


Spironolactone and canrenone, a major metabolite of the drug, are both more than 90% bound to plasma proteins. Spironolactone or its metabolites may cross the placenta. Canrenone, a major metabolite of spironolactone, is distributed into milk.

McEvoy, G.K. (ed.). American Hospital Formulary Service. AHFS Drug Information. American Society of Health-System Pharmacists, Bethesda, MD. 2007., p. 1983


5.6 Metabolism/Metabolites

Spironolactone is deacetylated to 7-thiospironolactone. 7-thiospironolactone is S-methylated to 7-thiomethylspironolactone or undergoes an elimination reaction to canrenone. 7-thiomethylspironolactone is reduced to 3-hydroxythiomethylspironolactone or 3-hydroxythiomethylspironolactone. Canrenone was originally thought to be the primary circulating metabolite, however more recent studies have demonstrated that the primary metabolite is actually 7-thiomethylspironolactone.


Spironolactone is rapidly and extensively metabolized to compounds that are excreted in the urine and faeces. It undergoes enterohepatic recirculation, but no unchanged drug appears in urine or feces. The metabolites of spironolactone can be divided into two main groups: those in which the sulfur moiety is retained and those in which the sulfur is removed by dethioacetylation. For many years, it was thought that the dethioacetylated metabolite, canrenone, was the major metabolite; however, with more specific analytical methods such as HPLC, 7alpha-thiomethylspirolactone was recognized as the major metabolite of spironolactone. This metabolite is formed by hydrolysis of the thioacetate group to form 7alpha-thiospirolactone (as an intermediate), followed by S-methylation to 7alpha-thiomethylspirolactone. This can then be hydroxylated to form 6-hydroxy-7alpha-thiomethylspirolactone and oxidized to form 7alpha-methylsulfinyl- and 7alpha-methylsulfonylspirolactone or via sulfoxidation to form 6alpha-hydroxy-7alpha-methylsulfinyl- and 6beta-hydroxy-7alpha-methylsulfonylspirolactone. For formation of the group of metabolites in which sulfur is removed, 7alpha-thiomethylspirolactone is also dethioacetylated to canrenone, which is further metabolized by three pathways: hydrolysis of the gamma-lactone ring to form canrenoate, which is excreted in the urine as a glucuronic ester, and, next, hydroxylation to form 15alpha-hydroxy-canrenone or reduction to produce several di-, tetra- and hexa-hydro derivatives. Canrenone and canrenoate are in equilibrium with one another. Not only spironolactone but several of its metabolites have biological activity; in decreasing order of potency, these are 7alpha-thiospirolactone, 7alpha-thiomethylspirolactone and canrenone.

IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V79 325 (2001)


Species differences were ... noted in the biotransformation of spironolactone. Canrenone was a principal extractable metabolite in rat and dog plasma, whereas in monkeys and humans, both canrenone and a very polar, unidentified metabolite were the major constituents. In the urine of all four species, canrenone was a principal constituent. Notable species differences in the metabolites of spironolactone in the feces were found, the pattern of metabolites in dog feces being markedly different from that in rats, monkeys or humans. Overall, it was concluded that the disposition and metabolism of spironolactone in monkeys, rather than that in rats or dogs, is closest to that in humans.

IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V79 326 (2001)


SIX METABOLITES OF SPIRONOLACTONE ... /HAVE/ BEEN DETECTED IN URINE OF TREATED SUBJECTS. ... /ONE IS/ DETHIOACETYLATED COMPD CANRENONE, 3-(3-OXO-17BETA-HYDROXY-4,6-ANDRO-STADIEN-17ALPHA-YL)PROPIONIC ACID GAMMA-LACTONE...

The Chemical Society. Foreign Compound Metabolism in Mammals Volume 3. London: The Chemical Society, 1975., p. 287


A FLUOROMETRIC METHOD WAS USED TO DETERMINE CONCN OF CANRENONE IN MILK FOLLOWING INGESTION OF SPIRONOLACTONE (ALDACTONE) 25 MG TWICE DAILY IN 28-YR-OLD FEMALE.

PMID:894512 PHELPS DL, KARIM A; J PHARM SCI 66: 1203 (1977)


5.7 Biological Half-Life

1.4 hours. Canrenone has a half life of 16.5 hours, 7--thiomethylspirolactone has a half life of 13.8 hours, and 6--hydroxy-7--thiomethylspirolactone has a half life of 15 hours.


... Nearly all absorbed spironolactone (> 90 %) is bound to plasma proteins and, with repeated dosing, a steady state is achieved within 8 days. After oral intake of a 100-mg dose, the plasma half-time of spironolactone was 1-2 h, the time to maximum plasma concentration was 2-3.2 hr, the maximum blood concentration was 92-148 ng/mL, the area under the concentration--time (0-24 hr) curve was 1430-1541 ng/mL per hr and the elimination half-time was 18-20 hr.

IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V79 325 (2001)


Following a single oral dose in healthy adults, the half-life of spironolactone averages 1.3-2 hours, and the half-life of 7alpha-thiomethylspironolactone averages 2.8 hours. The half-life of canrenone reportedly ranges from 13-24 hours. In multiple-dose studies, the steady-state plasma elimination half-life of canrenone averaged 19.2 hours when 200 mg of spironolactone was administered daily as a single dose and averaged 12.5 hours when 200 mg of the drug was administered daily in 4 equally divided doses.

McEvoy, G.K. (ed.). American Hospital Formulary Service. AHFS Drug Information. American Society of Health-System Pharmacists, Bethesda, MD. 2007., p. 1983


5.8 Mechanism of Action

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.


Spironolactone can exert antiandrogenic effects by several mechanisms: it can destroy testicular CYP and decrease 17alpha-hydroxylase activity, resulting in decreased testosterone synthesis; and it can inhibit 5alpha-dihydrotestosterone binding to cytosolic androgen receptor in the prostate.

IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V79 328 (2001)


Spironolactone exhibits antiandrogenic effects in males and females. The mechanism of antiandrogenic activity of spironolactone is complex and appears to involve several effects of the drug. Spironolactone decreases testosterone biosynthesis by inhibiting steroid 17alpha-monooxygenase (17alpha-hydroxylase) activity, possibly secondary to destruction of microsomal cytochrome P-450 in tissues with high steroid 17alpha-monooxygenase activity (e.g., testes, adrenals). The drug also appears to competitively inhibit binding of dihydrotestosterone to its cytoplasmic receptor protein, thus decreasing androgenic actions at target tissues. Spironolactone-induced increases in serum estradiol concentration also may contribute to its antiandrogenic activity, although such increases may not occur consistently; such increases appear to result from increased conversion of testosterone to estradiol. Spironolactone may have variable effects on serum 17-hydroxyprogesterone concentrations, possibly decreasing its production by inhibiting steroid 17alpha-monooxygenase activity or decreasing its conversion (with resultant accumulation) to androstenedione by inhibiting cytochrome P450-dependent 17alpha-hydroxyprogesterone aldolase (17,20-desmolase) activity. Serum progesterone concentrations may increase with the drug secondary to decreased hydroxylation (via steroid 17alpha-monooxygenase) to 17-hydroxyprogesterone. In children, compensatory increases in lutropin (luteinizing hormone, LH) and follicle-stimulating hormone (FSH) secretion can occur, probably secondary to the drug's antiandrogenic effects (i.e., a feedback response to decreasing serum testosterone concentrations and/or peripheral androgenic activity).

McEvoy, G.K. (ed.). American Hospital Formulary Service. AHFS Drug Information. American Society of Health-System Pharmacists, Bethesda, MD. 2007., p. 1983


MEDICATION (VET): Spironolactone is used most frequently and is a competitive antagonist of aldosterone. Aldosterone is elevated in animals with congestive heart failure in which the renin-angiotensin system is activated in response to hyponatremia, hyperkalemia, and reductions in blood pressure or cardiac output. Aldosterone is responsible for increasing sodium and chloride reabsorption and potassium and calcium excretion from renal tubules. Spironolactone competes with aldosterone at its receptor site, causing a mild diuresis and potassium retention.

Kahn, C.M. (Ed.); The Merck Veterinary Manual 9th ed. Merck & Co. Whitehouse Station, NJ. 2005, p. 2046


High concentrations of spironolactone have been reported to interfere with steroid biosynthesis by inhibiting 11 beta- and 18-, 21-, and 17 alpha-hydroxylase.

Hardman, J.G., L.E. Limbird, P.B., A.G. Gilman. Goodman and Gilman's The Pharmacological Basis of Therapeutics. 10th ed. New York, NY: McGraw-Hill, 2001., p. 780