DUZALLO COMPONENT ALLOPURINOL manufacturers and suppliers on PharmaCompass

Chemistry

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Also known as: 315-30-0, 1h-pyrazolo[3,4-d]pyrimidin-4-ol, 4-hydroxypyrazolo[3,4-d]pyrimidine, Allopurinolum, 4-hpp, Alopurinol
Molecular Formula
C5H4N4O
Molecular Weight
136.11  g/mol
InChI Key
OFCNXPDARWKPPY-UHFFFAOYSA-N
FDA UNII
63CZ7GJN5I

DUZALLO COMPONENT ALLOPURINOL
A XANTHINE OXIDASE inhibitor that decreases URIC ACID production. It also acts as an antimetabolite on some simpler organisms.
Allopurinol is a Xanthine Oxidase Inhibitor. The mechanism of action of allopurinol is as a Xanthine Oxidase Inhibitor.
1 2D Structure

DUZALLO COMPONENT ALLOPURINOL

2 Identification
2.1 Computed Descriptors
2.1.1 IUPAC Name
1,5-dihydropyrazolo[3,4-d]pyrimidin-4-one
2.1.2 InChI
InChI=1S/C5H4N4O/c10-5-3-1-8-9-4(3)6-2-7-5/h1-2H,(H2,6,7,8,9,10)
2.1.3 InChI Key
OFCNXPDARWKPPY-UHFFFAOYSA-N
2.2 Other Identifiers
2.2.1 UNII
63CZ7GJN5I
2.3 Synonyms
2.3.1 MeSH Synonyms

1. Allohexal

2. Allohexan

3. Alloprin

4. Allopurin

5. Allorin

6. Allpargin

7. Allural

8. Apulonga

9. Apurin

10. Atisuril

11. Bleminol

12. Caplenal

13. Capurate

14. Cellidrin

15. Embarin

16. Foligan

17. Hamarin

18. Jenapurinol

19. Lopurin

20. Lysuron

21. Milurit

22. Milurite

23. Novopurol

24. Pan Quimica

25. Progout

26. Pureduct

27. Purinol

28. Remid

29. Rimapurinol

30. Roucol

31. Suspendol

32. Tipuric

33. Uribenz

34. Uridocid

35. Uripurinol

36. Urosin

37. Urtias

38. Xanthomax

39. Xanturic

40. Zygout

41. Zyloprim

42. Zyloric

2.3.2 Depositor-Supplied Synonyms

1. 315-30-0

2. 1h-pyrazolo[3,4-d]pyrimidin-4-ol

3. 4-hydroxypyrazolo[3,4-d]pyrimidine

4. Allopurinolum

5. 4-hpp

6. Alopurinol

7. 1h-pyrazolo(3,4-d)pyrimidin-4-ol

8. 4-hydroxypyrazolopyrimidine

9. 4-hydroxy-1h-pyrazolo(3,4-d)pyrimidine

10. 4-hydroxy-3,4-pyrazolopyrimidine

11. 4-hydroxypyrazolo(3,4-d)pyrimidine

12. 1,5-dihydro-4h-pyrazolo[3,4-d]pyrimidin-4-one

13. Sigapurol

14. Uritas

15. 4-hydroxypyrazolyl(3,4-d)pyrimidine

16. 4h-pyrazolo(3,4-d)pyrimidin-4-one

17. 4'-hydroxypyrazolol(3,4-d)pyrimidine

18. Bw 56-158

19. Al-100

20. 1,5-dihydro-4h-pyrazolo(3,4-d)pyrimidin-4-one

21. Bw-56-158

22. 1,5-dihydro-4h-pyrazolo(3,4-d)pyrimidine-4-one

23. Chebi:40279

24. 63cz7gjn5i

25. Nsc-101655

26. Dtxsid4022573

27. Nsc1390

28. Nsc101655

29. 4-hydroxy-1h-pyrazolo[3,4-d]pyrimidine

30. Dtxcid502573

31. Duzallo Component Allopurinol

32. Allopurinol (mart.)

33. Allopurinol [mart.]

34. Allopurinol (usp-rs)

35. Allopurinol [usp-rs]

36. Allopurinol (ep Impurity)

37. Allopurinol [ep Impurity]

38. Allopurinol (ep Monograph)

39. Allopurinol [ep Monograph]

40. Allopurinol (usp Monograph)

41. Allopurinol [usp Monograph]

42. 4-hydroxypyrazolyl[3,4-d]pyrimidine

43. 4'-hydroxypyrazolol[3,4-d]pyrimidine

44. Allopurinolo

45. Zurinol

46. 4'-hpp

47. M04aa01

48. 1h-pyrazolo(3,4-d)pyrimdin-4-ol

49. 1,5-dihydro-4h-pyrazolo(3,4-d)pryimidin-4-one

50. 206-250-9

51. Zyloprim

52. Lopurin

53. Zyloric

54. Suspendol

55. Atisuril

56. Bleminol

57. Caplenal

58. Takanarumin

59. Uripurinol

60. Embarin

61. Foligan

62. Milurit

63. Progout

64. Urosin

65. Anoprolin

66. Cellidrin

67. Epidropal

68. Ailural

69. Allopur

70. Allural

71. Alositol

72. Bloxanth

73. Cosuric

74. Hamarin

75. Ledopur

76. Lysuron

77. Uricemil

78. Uriprim

79. Xanturat

80. Aloral

81. Anzief

82. Apurin

83. Apurol

84. Geapur

85. Gotax

86. Remid

87. Urbol

88. Urolit

89. Urtias

90. Ketobun-a

91. Apulonga

92. Dabrosin

93. Dabroson

94. Ketanrift

95. Miniplanor

96. Nektrohan

97. Adenock

98. Allozym

99. Aluline

100. Gichtex

101. Monarch

102. Riball

103. 1h-pyrazolo[3,4-d]pyrimidin-4(5h)-one

104. Hexanuret

105. Epuric

106. Allo-puren

107. Allopurinol(i)

108. Dura Al

109. 180749-08-0

110. 73334-58-4

111. 180749-06-8

112. Urtias 100

113. 1h-pyrazolo[3,4-d]pyrimidin-4(7h)-one

114. 2h-pyrazolo[3,4-d]pyrimidin-4-ol

115. Nsc-1390

116. Alopurinol [inn-spanish]

117. Allopurinolum [inn-latin]

118. 1h-pyrazolo[3,4-d]pyrimidin-4(2h)-one

119. 180749-09-1

120. Zyloprim (tn)

121. 916980-04-6

122. Mfcd00599413

123. 1,5-dihydropyrazolo[3,4-d]pyrimidin-4-one

124. 9002-17-9

125. B. W. 56-158

126. 4h-pyrazolo(3,4-d)pyrimidin-4-one, 1,5-dihydro-

127. 4h-pyrazolo[3,4-d]pyrimidin-4-one, 1,5-dihydro-

128. 180749-07-9

129. 184789-03-5

130. 1h,4h,7h-pyrazolo[3,4-d]pyrimidin-4-one

131. Mls000069453

132. 4h-pyrazolo[3,4-d]pyrimidin-4-one, 1,2-dihydro-

133. 1h,2h,4h-pyrazolo[3,4-d]pyrimidin-4-one

134. Xanthine Oxidase

135. Smr000059083

136. 1h-pyrazolo[3,4-d]pyrimidin-4-ol (9ci)

137. 291279-53-3

138. 4h-pyrazolo[3,4-d]pyrimidin-4-one, 1,7-dihydro- (9ci)

139. Ncgc00015094-02

140. Ncgc00094580-04

141. 4h-pyrazolo[3,4-d]pyrimidin-4-one, 2,5-dihydro- (9ci)

142. 4h-pyrazolo[3,4-d]pyrimidin-4-one, 2,7-dihydro- (9ci)

143. Bw-56158

144. 1h,4h,5h-pyrazolo[3,4-d]pyrimidin-4-one

145. 1,5-dihydro-pyrazolo[3,4-d]pyrimidin-4-one

146. 4h-pyrazolo[3,4-d]pyrimidin-4-one, 1,7-dihydro-

147. 4h-pyrazolo[3, 1,5-dihydro-

148. Ailurial

149. Wln: T56 Bmn Gn Inj Fq

150. Nsc 1390

151. Cas-315-30-0

152. Ccris 626

153. Nsc 101655

154. Hsdb 3004

155. Sr-05000001983

156. Einecs 206-250-9

157. Unii-63cz7gjn5i

158. Uricto

159. Ath008

160. 4-hydroxypyrazol[3,4-d]pyrimidine

161. Prestwick_511

162. Xanthomax-100

163. Xanthomax-300

164. Aluline 100

165. Aluline 300

166. Hamarin 100

167. Hamarin 300

168. Zyloric-300

169. Allopurinol [usan:usp:inn:ban:jan]

170. Allopurinol (standard)

171. Allopurinol (zyloprim)

172. Spectrum_000026

173. Allopurinol - Ep Grade

174. Allopurinol [mi]

175. Opera_id_1680

176. Spectrum2_000098

177. Spectrum3_000289

178. Spectrum4_000135

179. Spectrum5_000768

180. Allopurinol [inn]

181. Allopurinol [jan]

182. Lopac-a-8003

183. 1,4-d]pyrimidin-4-one

184. Allopurinol [hsdb]

185. Allopurinol [usan]

186. A 8003

187. Cid_2094

188. Schembl4627

189. A1bd4

190. Chembl1467

191. Nciopen2_001825

192. Lopac0_000102

193. Allopurinol [who-dd]

194. Allopurinol [who-ip]

195. Bspbio_001798

196. Kbiogr_000550

197. Kbioss_000386

198. Mls001148183

199. Us9138393, Allopurinol

200. Us9144538, Allopurinol

201. Divk1c_000685

202. Spectrum1500108

203. Spbio_000056

204. Allopurinolum [who-ip]

205. Gtpl6795

206. Schembl1128219

207. Allopurinol (jp18/usp/inn)

208. Bdbm35440

209. Hms502c07

210. Hy-b0219r

211. Kbio1_000685

212. Kbio2_000386

213. Kbio2_002954

214. Kbio2_005522

215. Kbio3_001298

216. Allopurinol [orange Book]

217. Ninds_000685

218. Bdbm181133

219. Hms1920a15

220. Hms2091g15

221. Hms2234m09

222. Hms3259k13

223. Hms3260e06

224. Hms3371i11

225. Hms3651o13

226. Hms3714l22

227. Pharmakon1600-01500108

228. Bcp26973

229. Hy-b0219

230. Str05189

231. Tox21_110082

232. Tox21_200922

233. Tox21_500102

234. 4-hydroxy-pyrazolo[3,4-d]pyrimidin

235. Ac-019

236. Bbl009959

237. Bdbm50016784

238. Bdbm50140241

239. Ccg-38916

240. Nsc755858

241. S1630

242. Sc1118

243. Sc2251

244. Stk378584

245. Stk711106

246. Akos000267490

247. Akos000269759

248. Akos024255717

249. Tox21_110082_1

250. Allopurinol, Xanthine Oxidase Inhibitor

251. Ccg-204197

252. Ccg-221406

253. Ccg-266128

254. Db00437

255. Fa17288

256. Lp00102

257. Nc00492

258. Nsc-755858

259. Sb10164

260. Sdccgsbi-0050090.p005

261. Idi1_000685

262. Ncgc00015094-01

263. Ncgc00015094-03

264. Ncgc00015094-04

265. Ncgc00015094-05

266. Ncgc00015094-06

267. Ncgc00015094-07

268. Ncgc00015094-08

269. Ncgc00015094-18

270. Ncgc00015094-22

271. Ncgc00091134-01

272. Ncgc00091134-02

273. Ncgc00091134-03

274. Ncgc00094580-01

275. Ncgc00094580-02

276. Ncgc00094580-05

277. Ncgc00188948-01

278. Ncgc00258476-01

279. Ncgc00260787-01

280. Fa160361

281. Fa162226

282. Ts-00028

283. Sbi-0050090.p004

284. Db-065332

285. Db-261136

286. Db-272461

287. Db-272465

288. Db-272466

289. Db-272469

290. 2h-pyrazolo[3,4-d]pyrimidin-4-ol (9ci)

291. A0907

292. Eu-0100102

293. Ns00000618

294. Sw199406-4

295. 1,5-dihydropyrazolo[3,4-d]-pyrimidin-4-one

296. En300-34144

297. Vu0611037-1

298. Bim-0061756.0001

299. D00224

300. F18007

301. Ab00173448-03

302. Ab00173448-04

303. Ab00173448_05

304. Ab01274719-01

305. Ab01274719_02

306. Ab-323/25048497

307. Allopurinol (4-hydroxypyrazolo[3,4-d]pyrimidine)

308. Q412486

309. Sr-01000075595

310. 4h-pyrazolo[3,4-d]pyrimidin-4-one, 2,5-dihydro-

311. Sr-01000075595-1

312. Sr-05000001983-1

313. Sr-05000001983-2

314. Brd-k86307448-001-16-7

315. Brd-k86307448-001-17-5

316. Brd-k86307448-001-19-1

317. F2173-0394

318. F3329-0375

319. Z104486670

320. 4h-pyrazolo[3,4-d]pyrimidin-4-one, 1,2-dihydro- (9ci)

321. 4h-pyrazolo[3,4-d]pyrimidin-4-one, 2,7-dihydro-

322. Allopurinol, British Pharmacopoeia (bp) Reference Standard

323. Allopurinol, European Pharmacopoeia (ep) Reference Standard

324. Allopurinol, United States Pharmacopeia (usp) Reference Standard

325. 1,5-dihydro-4h-pyrazolo[3,4-d]pyrimidin-4-one Synonym: Allopurinol

326. Allopurinol, Pharmaceutical Secondary Standard; Certified Reference Material

327. Inchi=1/c5h4n4o/c10-5-3-1-8-9-4(3)6-2-7-5/h1-2h,(h2,6,7,8,9,10

328. 1,5-dihydro-4h-pyrazolo[3,4-d]pyrimidin-4-one;4-hydroxypyrazolo[3,4-d]pyrimidine;4-oxopyrazolo[3,4-d]pyrimidine

329. 1,5dihydro-4h-pyrazolo[3,4-d]pyrimidin-4-one;4-hydroxypyrazolo[3,4-d]pyrimidine;4-oxopyrazolo[3,4-d]pyrimidine

2.4 Create Date
2019-01-15
3 Chemical and Physical Properties
Molecular Weight 136.11 g/mol
Molecular Formula C5H4N4O
XLogP3-0.7
Hydrogen Bond Donor Count2
Hydrogen Bond Acceptor Count3
Rotatable Bond Count0
Exact Mass Da
Monoisotopic Mass Da
Topological Polar Surface Area70.1
Heavy Atom Count10
Formal Charge0
Complexity190
Isotope Atom Count0
Defined Atom Stereocenter Count0
Undefined Atom Stereocenter Count0
Defined Bond Stereocenter Count0
Undefined Bond Stereocenter Count0
Covalently Bonded Unit Count1
4 Drug and Medication Information
4.1 Therapeutic Uses

Antimetabolites; Antimetabolites, Antineoplastic; Enzyme Inhibitors; Gout Suppressants

National Library of Medicine's Medical Subject Headings online file (MeSH, 2009)


Allopurinol is indicated in the management of patients with signs and symptoms of primary or secondary gout (acute attacks, tophi, joint destruction, uric acid lithiasis, and/or nephropathy). /Included in US product label/

US Natl Inst Health; DailyMed. Current Medication Information for Allopurinol (allopurinol) tablet (April 2007). Available from, as of February 24, 2010: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?id=3795


Allopurinol is indicated in the management of patients with leukemia, lymphoma and malignancies who are receiving cancer therapy which causes elevations of serum and urinary uric acid levels. Treatment with allopurinol should be discontinued when the potential for over production of uric acid is no longer present. /Included in US product label/

US Natl Inst Health; DailyMed. Current Medication Information for Allopurinol (allopurinol) tablet (April 2007). Available from, as of February 24, 2010: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?id=3795


Allopurinol is indicated in the management of patients with recurrent calcium oxalate calculi whose daily uric acid excretion exceeds 800 mg/day in male patients and 750 mg/day in female patients. Therapy in such patients should be carefully assessed initially and reassessed periodically to determine in each case that treatment is beneficial and that the benefits outweigh the risks. /Included in US product label/

US Natl Inst Health; DailyMed. Current Medication Information for Allopurinol (allopurinol) tablet (April 2007). Available from, as of February 24, 2010: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?id=3795


For more Therapeutic Uses (Complete) data for Allopurinol (9 total), please visit the HSDB record page.


4.2 Drug Warning

Since allopurinol and oxypurinol are distributed into milk, allopurinol should be used with caution in nursing women.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3690


Results of early clinical studies and experience suggested that some allopurinol-induced adverse effects (eg, acute attacks of gout, rash) occurred in more than 1% of patients, but current experience suggests that adverse effects of the drug occur in less than 1% of patients. The reduced incidence in adverse effects observed with more recent experience may have resulted in part from initiating therapy with the drug more gradually and following current prescribing precautions and recommendations.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3689


The most common adverse effect of oral allopurinol is a pruritic maculopapular rash. Dermatitides of the exfoliative, urticarial, erythematous, eczematoid, hemorrhagic, and purpuric types have also occurred. Alopecia, fever, and malaise may also occur alone or in conjunction with dermatitis. In addition, severe furunculoses of the nose, cellulitis, and ichthyosis have been reported. The incidence of rash may be increased in patients with renal insufficiency. Skin reactions may be delayed and have been reported to occur as long as 2 years after initiating allopurinol therapy. Rarely, skin rash may be followed by severe hypersensitivity reactions which may sometimes be fatal. Some patients who have developed severe dermatitis have also developed cataracts (including a case of toxic cataracts), but the exact relationship between allopurinol and cataracts has not been established. Pruritus, onycholysis, and lichen planus have also occurred rarely in patients receiving allopurinol. Facial edema, sweating, and skin edema have also occurred rarely, but a causal relationship to the drug has not been established.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3689


Local injection site reactions have been reported in patients receiving allopurinol sodium iv.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3689


For more Drug Warnings (Complete) data for Allopurinol (28 total), please visit the HSDB record page.


4.3 Drug Indication

Allopurinol is indicated in: 1) the management of patients with signs and symptoms of primary or secondary gout (acute attacks, tophi, joint destruction, uric acid lithiasis, and/or nephropathy). 2) the management of patients with leukemia, lymphoma and malignancies who are receiving cancer therapy which causes elevations of serum and urinary uric acid levels. Treatment with allopurinol should be discontinued when the potential for overproduction of uric acid is no longer present. 3) the management of patients with recurrent calcium oxalate calculi whose daily uric acid excretion exceeds 800 mg/day in male patients and 750 mg/day in female patients. Therapy in such patients should be carefully assessed initially and reassessed periodically to determine in each case that treatment is beneficial and that the benefits outweigh the risks.


FDA Label



Allopurinol, a xanthine oxidase inhibitor, is a urate-lowering medication.


5 Pharmacology and Biochemistry
5.1 MeSH Pharmacological Classification

Antimetabolites

Drugs that are chemically similar to naturally occurring metabolites, but differ enough to interfere with normal metabolic pathways. (From AMA Drug Evaluations Annual, 1994, p2033) (See all compounds classified as Antimetabolites.)


Enzyme Inhibitors

Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction. (See all compounds classified as Enzyme Inhibitors.)


Free Radical Scavengers

Substances that eliminate free radicals. Among other effects, they protect PANCREATIC ISLETS against damage by CYTOKINES and prevent myocardial and pulmonary REPERFUSION INJURY. (See all compounds classified as Free Radical Scavengers.)


Gout Suppressants

Agents that increase uric acid excretion by the kidney (URICOSURIC AGENTS), decrease uric acid production (antihyperuricemics), or alleviate the pain and inflammation of acute attacks of gout. (See all compounds classified as Gout Suppressants.)


5.2 FDA Pharmacological Classification
5.2.1 Active Moiety
ALLOPURINOL
5.2.2 FDA UNII
63CZ7GJN5I
5.2.3 Pharmacological Classes
Xanthine Oxidase Inhibitors [MoA]; Xanthine Oxidase Inhibitor [EPC]
5.3 ATC Code

M04AA01

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


M - Musculo-skeletal system

M04 - Antigout preparations

M04A - Antigout preparations

M04AA - Preparations inhibiting uric acid production

M04AA01 - Allopurinol


M04AA01


5.4 Absorption, Distribution and Excretion

Absorption

This drug is about 90% absorbed from the gastrointestinal tract. Peak plasma levels normally occur at 1.5 hours and 4.5 hours post-dose for allopurinol and oxipurinol respectively. Following one oral dose of 300 mg of allopurinol, maximum plasma levels of about 3 mcg/mL of allopurinol and 6.5 mcg/mL of oxipurinol were measured.


Route of Elimination

Approximately 80% of orally ingested allopurinol is found excreted in the urine as various metabolites. About 20% of ingested allopurinol is excreted in the feces.


Volume of Distribution

Allopurinol and oxypurinol are both substrates for the enzyme xanthine oxidase, which is present in the cytoplasm of endothelial cells of capillaries, including sinusoids, with the highest activity demonstrated in the liver and intestinal lining. Tissue concentrations of allopurinol have not yet been reported in humans, however, it is probable that allopurinol and the metabolite oxypurinol would be measured in the highest concentrations in the abovementioned tissues. In animals, allopurinol concentrations are found to reach the highest levels in the blood, liver, intestine and heart, and lowest in the brain and lung tissues.


Clearance

Since allopurinol and its metabolites are mainly eliminated by the kidney, accumulation of this drug can occur in patients with renal dysfunction or failure, and the dose of allopurinol should, therefore, be reduced. With a creatinine clearance of 10 to 20 mL/min, a daily dosage of 200 mg of allopurinol is suitable. When the creatinine clearance is less than 10 mL/min, the daily dosage should not be higher than 100 mg. With severe renal impairment (creatinine clearance measured at less than 3 mL/min) a longer interval between doses may be required.


Following oral administration, approximately 80-90% of a dose of allopurinol is absorbed from the GI tract. Peak plasma concentrations of allopurinol are reached 2-6 hours after a usual dose.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3691


Allopurinol is absorbed poorly following rectal administration of the drug as suppositories (in a cocoa butter or polyethylene glycol base). Plasma allopurinol or oxipurinol concentrations have been minimal or undetectable following such rectal administration.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3691


Following oral administration of single 100- or 300-mg dose of allopurinol in healthy adult males in one study, peak plasma allopurinol concentrations of about 0.5 or 1.4 ug/mL, respectively, occurred in about 1-2 hours, while peak oxypurinol (the active metabolite of allopurinol) concentrations of about 2.4 and 6.4 ug/mL, respectively, were reached within about 3-4 hours. In the same study, following iv infusion over 30 minutes of a single 100- or 300-mg dose of allopurinol (as allopurinol sodium), peak plasma concentrations of about 1.6 and 5.1 ug/mL, respectively, occurred in about 30 minutes, while peak oxypurinol concentrations of about 2.2 and 6.2 ug/mL, respectively, were reached within about 4 hours.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3691


Following intravenous administration in six healthy male and female subjects, allopurinol was rapidly eliminated from the systemic circulation primarily via oxidative metabolism to oxypurinol, with no detectable plasma concentration of allopurinol after 5 hours post dosing. Approximately 12% of the allopurinol intravenous dose was excreted unchanged, 76% excreted as oxypurinol, and the remaining dose excreted as riboside conjugates in the urine. The rapid conversion of allopurinol to oxypurinol was not significantly different after repeated allopurinol dosing. ... Oxypurinol was primarily eliminated unchanged in urine by glomerular filtration and tubular reabsorption, with a net renal clearance of about 30 mL/min.

US Natl Inst Health; DailyMed. Current Medication Information for Allopurinol (allopurinol) tablet (April 2007). Available from, as of February 24, 2010: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?id=3795


For more Absorption, Distribution and Excretion (Complete) data for Allopurinol (13 total), please visit the HSDB record page.


5.5 Metabolism/Metabolites

Allopurinol is rapidly metabolized to the corresponding xanthine analog, oxipurinol (alloxanthine), which is also an inhibitor of xanthine oxidase enzyme. Both allopurinol and oxypurinol inhibit the action of this enzyme. Allopurinol and oxypurinol are also converted by the purine salvage pathway to their respective ribonucleotides. The effect of these ribonucleotides related to the hypouricemic action of allopurinol in humans is not fully elucidated to this date. These metabolites may act to inhibit de novo purine biosynthesis by inhibiting the enzyme, _amidophosphoribosyltransferase_. The ribonucleotides have not been found to be incorporated in DNA.


Allopurinol and allopurinol sodium are rapidly metabolized by xanthine oxidase to oxypurinol, which is pharmacologically active. Rapid metabolism of allopurinol to oxypurinol does not seem to be affected substantially during multiple dosing. Pharmacokinetic parameters (eg, AUC, plasma elimination half-lives) of oxypurinol appear to be similar following oral administration of allopurinol and iv administration of allopurinol sodium.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3691


Both allopurinol and oxypurinol are conjugated and form their respective ribonucleosides.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3691


Allopurinol-1-riboside, a major metabolite of allopurinol, is commonly thought to be directly synthesized by purine nucleoside phosphorylase (PNP) in vivo. As this enzyme is otherwise believed to function in vivo primarily in the direction of nucleoside breakdown, we have determined by high performance liquid chromatography and a conventional chromatographic method the urinary metabolites of allopurinol in a child deficient of PNP. In this patient approximately 40% of urinary allopurinol metabolites consisted of allopurinol-1-riboside, thus proving the possibility of indirect formation of allopurinol-1-riboside via allopurinol-1-ribotide in vivo, catalysed by hypoxanthine guanine phosphoribosyltransferase (HGPRT) and a phosphatase.

PMID:6409116 Reiter S et al; Biochem Pharmacol 32 (14): 2167-74 (1983).


... The major and active metabolite, oxypurinol, is detected in the circulation within 15 minutes of allopurinol administration. Oxypurinol concentrations are higher than those of the parent drug and accumulation occurs during long term administration. ...Oxypurinol is eliminated by the kidney and has a much longer elimination half-life than allopurinol. Oxypurinol accumulates in patients with renal dysfunction; hence allopurinol dosages should be adjusted in such patients. ...

PMID:3536254 Murrell GA, Rapeport WG; Clin Pharmacokinet 11 (5): 343-53 (1986).


For more Metabolism/Metabolites (Complete) data for Allopurinol (7 total), please visit the HSDB record page.


Hepatic Route of Elimination: Approximately 20% of the ingested allopurinol is excreted in the feces. Half Life: 1-3 hours


5.6 Biological Half-Life

The plasma half-life of allopurinol is 1-2 hours, due to its rapid renal clearance.


The half-lives of allopurinol and oxypurinol are about 1-3 hours and 18-30 hours, respectively, in patients with normal renal function and are increased in patients with renal impairment.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3691


Allopurinol is rapidly cleared from plasma with half-time of 2-3 hr, primarily by conversion to alloxanthine.

Gilman, A.G., T.W. Rall, A.S. Nies and P. Taylor (eds.). Goodman and Gilman's The Pharmacological Basis of Therapeutics. 8th ed. New York, NY. Pergamon Press, 1990., p. 677


Serum half-life of allopurinol is 39 min.

PMID:639435 Hande K et al; Clin Pharmacol Ther23 (5): 598-605 (1978)


5.7 Mechanism of Action

Allopurinol is a structural analog of the natural purine base, hypoxanthine. After ingestion, allopurinol is metabolized to its active metabolite, oxypurinol (_alloxanthine_) in the liver, which acts as an inhibitor of xanthine oxidase enzyme. Allopurinol and its active metabolite inhibit xanthine oxidase, the enzyme that converts hypoxanthine to xanthine and xanthine to uric acid. Inhibition of this enzyme is responsible for the effects of allopurinol. This drug increases the reutilization of hypoxanthine and xanthine for nucleotide and nucleic acid synthesis by a process that involves the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRTase). This process results in an increased nucleotide concentration, which causes feedback inhibition of de novo purine synthesis. The end result is decreased urine and serum uric acid concentrations, which decreases the incidence of gout symptoms. Accompanying the reduction of serum uric acid by allopurinol is an increase in the serum and urine concentrations of hypoxanthine and xanthine (due to inhibition of xanthine oxidase). In the absence of allopurinol, regular urinary excretion of oxypurines almost entirely occurs in the form of uric acid. After the ingestion of allopurinol, the contents of excreted urine are hypoxanthine, xanthine, and uric acid. Because each substance has its own individual solubility, the concentration of uric acid in plasma is decreased without exposing the renal tissues to a high load of uric acid, thereby decreasing the risk of crystalluria. By lowering the uric acid concentration in the plasma below its limits of solubility, allopurinol encourages the dissolution of gout tophi. Although the levels of hypoxanthine and xanthine are found to be increased after allopurinol ingestion, the risk of deposition in renal tissues is less than that of uric acid, as they become more soluble and are rapidly excreted by the kidney.


Allopurinol inhibits xanthine oxidase, the enzyme that catalyzes the conversion of hypoxanthine to xanthine and of xanthine to uric acid. Oxypurinol, a metabolite of allopurinol, also inhibits xanthine oxidase. By inhibiting xanthine oxidase, allopurinol and its metabolite block conversion of the oxypurines (hypoxanthine and xanthine) to uric acid, thus decreasing serum and urine concentrations of uric acid. The drug differs, therefore, from uricosuric agents which lower serum urate concentrations by promoting urinary excretion of uric acid. Xanthine oxidase concentrations are not altered by long-term administration of the drug.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3690


Allopurinol does not directly interfere with purine nucleotide or nucleic acid synthesis. The drug, however, indirectly increases oxypurine and allopurinol ribonucleotide concentrations and decreases phosphoribosylpyrophosphate concentrations, thus decreasing de novo purine biosynthesis by pseudofeedback inhibition. In addition, allopurinol increases the incorporation of hypoxanthine and xanthine into DNA and RNA, thereby further decreasing serum urate concentrations. Allopurinol may produce a deficit of total purines (uric acid and oxypurines) amounting to several hundred mg daily.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3690


Accompanying the decrease in uric acid produced by allopurinol is an increase in serum and urine concentrations of hypoxanthine and xanthine. Plasma concentrations of these oxypurines do not, however, rise commensurately with the fall in serum urate concentrations and are often 20-30% less than would be expected in view of urate concentrations prior to allopurinol therapy. This discrepancy occurs because renal clearance of the oxypurines is at least 10 times greater than that of uric acid. In addition, normal urinary purine output is almost exclusively uric acid, but after treatment with allopurinol, it is composed of uric acid, xanthine, and hypoxanthine, each having independent solubility. Thus, the risk of crystalluria is reduced. Alkalinization of the urine increases the solubility of the purines, further minimizing the risk of crystalluria. Decreased tubular transport of uric acid also results in increased renal reabsorption of calcium and decreased calcium excretion.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3691


Allopurinol also interferes with de novo pyrimidine nucleotide synthesis by inhibiting orotidine 5'-phosphate decarboxylase. Secondary orotic aciduria and orotidinuria result. Orotic acid is highly insoluble and could form a heavy sediment of urinary crystals; however, the increased excretion of orotic acid and orotidine rarely exceeds 10% of the total pyrimidines synthesized by the body. In addition, enhanced conversion of uridine to uridine 5'-monophosphate usually occurs and, therefore, this partial inhibition of pyrimidine synthesis is considered innocuous.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3691


Allopurinol may also inhibit hepatic microsomal enzymes. Allopurinol is not cytotoxic and has no effect on transplantable tumors. The drug has no analgesic, anti-inflammatory, or uricosuric activity.

American Society of Health System Pharmacists; AHFS Drug Information 2009. Bethesda, MD. (2009), p. 3691


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