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2D Structure
Also known as: 95233-18-4, Mepron, Wellvone, Acuvel, Atavaquone, 566c80
Molecular Formula
C22H19ClO3
Molecular Weight
366.8  g/mol
InChI Key
BSJMWHQBCZFXBR-UHFFFAOYSA-N
FDA UNII
F1W7QUV0KI

A hydroxynaphthoquinone that has antimicrobial activity and is being used in antimalarial protocols.
Atovaquone is an Antimalarial and Antiprotozoal.
1 2D Structure

2D Structure

2 Identification
2.1 Computed Descriptors
2.1.1 IUPAC Name
3-[4-(4-chlorophenyl)cyclohexyl]-4-hydroxynaphthalene-1,2-dione
2.1.2 InChI
InChI=1S/C22H19ClO3/c23-16-11-9-14(10-12-16)13-5-7-15(8-6-13)19-20(24)17-3-1-2-4-18(17)21(25)22(19)26/h1-4,9-13,15,24H,5-8H2
2.1.3 InChI Key
BSJMWHQBCZFXBR-UHFFFAOYSA-N
2.1.4 Canonical SMILES
C1CC(CCC1C2=CC=C(C=C2)Cl)C3=C(C4=CC=CC=C4C(=O)C3=O)O
2.2 Other Identifiers
2.2.1 UNII
F1W7QUV0KI
2.3 Synonyms
2.3.1 MeSH Synonyms

1. 2-(4-(4'-chlorophenyl)cyclohexyl)-3-hydroxy-1,4-naphthoquinone

2. 2-(trans-4-(4-chlorophenyl)cyclohexyl)-3-hydroxy-1,4-naphthoquinone

3. 566c

4. 566c80

5. 566c80 Hydroxynaphthoquinone

6. Compound 566

7. Hydroxynaphthoquinone 566c80

8. Hydroxynaphthoquinone, 566c80

9. Mepron

10. Wellvone

2.3.2 Depositor-Supplied Synonyms

1. 95233-18-4

2. Mepron

3. Wellvone

4. Acuvel

5. Atavaquone

6. 566c80

7. 94015-53-9

8. Cis-atovaquone

9. 137732-39-9

10. Mepron (antipneumocystic)

11. 566c

12. Bw 566c

13. 3-[4-(4-chlorophenyl)cyclohexyl]-4-hydroxynaphthalene-1,2-dione

14. Atovaquone (atavaquone)

15. 2-(trans-4-(p-chlorophenyl)cyclohexyl)-3-hydroxy-1,4-naphthoquinone

16. F1w7quv0ki

17. 2-(4-(4-chlorophenyl)cyclohexyl)-3-hydroxy-1,4-naphthoquinone

18. Nsc-759582

19. 2-[trans-4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthoquinone

20. 2-(trans-4-(4-chlorophenyl)cyclohexyl)-3-hydroxy-1,4-naphthalenedione

21. Y883p1z2lt

22. Chebi:575568

23. 2-[trans-4-(4-chlorophenyl)cyclohexyl]-3-hydroxynaphthalene-1,4-dione

24. Ncgc00016961-01

25. Atovaquone 100 Microg/ml In Acetonitrile

26. 2-(4-(4-chlorophenyl)cyclohexyl)-3-hydroxynaphthalene-1,4-dione

27. Cas-95233-18-4

28. 2-[trans-4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthalenedione

29. Dsstox_cid_2629

30. Trans-2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthalenedione

31. 1,4-naphthalenedione, 2-(4-(4-chlorophenyl)cyclohexyl)-3-hydroxy-, Trans-

32. 2-((1r,4r)-4-(4-chlorophenyl)cyclohexyl)-3-hydroxynaphthalene-1,4-dione

33. Dsstox_rid_76664

34. Dsstox_gsid_22629

35. 2-(cis-4-(4-chlorophenyl)cyclohexyl)-3-hydroxy-1,4-naphthalenedione

36. 2-[trans-4-(p-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthoquinone

37. Cis-2-(4-(4-chlorophenyl)cyclohexyl)-3-hydroxy-1,4-naphthoquinone

38. 1,4-naphthalenedione, 2-(cis-4-(4-chlorophenyl)cyclohexyl)-3-hydroxy-

39. 1,4-naphthalenedione, 2-[cis-4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-

40. 2-(trans-4-(4-chlorophenyl)cyclohexyl)-3-hydroxynaphthalene-1,4-dione

41. Drg-0084

42. Bw 566c-80

43. Mepron (tn)

44. Bw-a 566c

45. Hsdb 7083

46. Sr-05000001438

47. Bw-566c-80

48. Atovacuona

49. Crl-8131 & Atovaquone

50. Unii-y883p1z2lt

51. Atovaquona

52. 2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthoquinone

53. Atovaquone & Interleukin 12

54. 2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-naphthalene-1,4-dione

55. 2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxynaphthalene-1,4-dione

56. Cis-2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthoquinone

57. Trans-2-(4-(4-chlorophenyl) Cyclohexyl)-3-hydroxynaphthalene-1,4-dione

58. Ato & Il-12

59. Atovaquone [usan:usp:inn:ban]

60. Atovaquone-[d5]

61. Atovaquone- Bio-x

62. Bw 566c80

63. Spectrum_001743

64. Starbld0018905

65. Atovaquone [mi]

66. Specplus_000686

67. Atovaquone [inn]

68. Atovaquone [jan]

69. Prestwick0_000534

70. Prestwick1_000534

71. Prestwick2_000534

72. Prestwick3_000534

73. Spectrum2_001665

74. Spectrum3_000991

75. Spectrum4_001117

76. Spectrum5_001382

77. Unii-f1w7quv0ki

78. Atovaquone [hsdb]

79. Atovaquone [usan]

80. Atovaquone Ep Impurity B

81. Atovaquone [vandf]

82. Atovaquone [mart.]

83. Atovaquone [usp-rs]

84. Atovaquone [who-dd]

85. Schembl21694

86. Schembl21695

87. Atovaquone (jan/usp/inn)

88. Bspbio_000547

89. Bspbio_002681

90. Kbiogr_001594

91. Kbioss_002223

92. Atovaquone Related Compound A

93. Mls002153863

94. Bidd:gt0849

95. Divk1c_006782

96. Schembl637069

97. Spectrum1504210

98. Spbio_001849

99. Spbio_002468

100. Bpbio1_000603

101. Chembl222334

102. Chembl471792

103. Chembl519462

104. Gtpl9695

105. Schembl1542719

106. Schembl1649508

107. Schembl9975142

108. Schembl9975229

109. Atovaquone [orange Book]

110. Atovaquone, >=98% (hplc)

111. Cis-atovaquone (racemic)

112. Dtxsid7022629

113. Atovaquone For System Suitability

114. Chebi:95346

115. Kbio1_001726

116. Kbio2_002223

117. Kbio2_004791

118. Kbio2_007359

119. Kbio3_001901

120. Atovaquone [ep Monograph]

121. Dtxsid20916694

122. Atovaquone [usp Monograph]

123. Bdbm192009

124. Hms1569l09

125. Hms1922f19

126. Hms2089m14

127. Hms2093c10

128. Hms2096l09

129. Hms2235n08

130. Hms3369n09

131. Hms3651n20

132. Hms3713l09

133. Pharmakon1600-01504210

134. Amy15339

135. Bcp09477

136. Malarone Component Atovaquone

137. Tox21_110714

138. 3-[4-(4-chlorophenyl)cyclohexyl]-4-hydroxy-naphthalene-1,2-dione

139. Atovaquone Related Compound A [usp]

140. Ccg-39090

141. Fd7252

142. Mfcd00889188

143. Nsc759582

144. S3079

145. Stk636160

146. Trans-2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthoquinone

147. Zinc12504271

148. 1,4-naphthalenedione, 2-(trans-4-(4-chlorophenyl)cyclohexyl)-3-hydroxy-

149. 2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-dihydronaphthalene-1,4-dione

150. Akos005567953

151. Akos015895691

152. Akos015961933

153. Tox21_110714_1

154. Zinc100017856

155. Zinc100345537

156. Zinc116473771

157. Zinc299873031

158. Atovaquone Component Of Malarone

159. Bw-556c-80

160. Ccg-220534

161. Db01117

162. Nsc 759582

163. Ncgc00016961-02

164. Ncgc00016961-03

165. Ncgc00016961-04

166. Ncgc00016961-06

167. Ncgc00016961-07

168. Ncgc00016961-11

169. Ncgc00095113-01

170. Ncgc00095113-02

171. Ac-30251

172. As-12809

173. Ba164228

174. Hy-13832

175. Smr001233220

176. Sbi-0052893.p002

177. Ab00513855

178. Ft-0602868

179. Sw219222-1

180. Malarone Pediatric Component Atovaquone

181. A13708

182. Atovaquone Related Compound A [usp-rs]

183. C06835

184. D00236

185. F18448

186. Ab00053222-03

187. Ab00053222_04

188. Ab00053222_05

189. Atovaquone Component Of Malarone Pediatric

190. 233a184

191. A853147

192. Q418179

193. Atovaquone Related Compound A [usp Impurity]

194. Sr-05000001438-1

195. Sr-05000001438-2

196. Sr-05000001438-4

197. Sr-05000001438-5

198. Z1541632806

199. 2-[4-(4-chlorophenyl)cyclohexy]-3-hydroxy-1,4-naphthoquinone

200. 2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-napthoquinone

201. 2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1.4-naphthoquinone

202. 2-hydroxy-3-[4-(4-chlorophenyl)cyclohexyl]-1,4-naphthoquinone

203. 3-[4-(p-chlorophenyl)cyclohexyl]-4-hydroxy-1,2-naphthoquinone

204. 1,2-naphthalenedione, 3-[4-(4-chlorophenyl)cyclohexyl]-4-hydroxy-

205. 1,4-naphthalenedione, 2-(4-(4-chlorophenyl)cyclohexyl)-3-hydroxy-

206. 2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxynaphthoquinone, Trans-

207. 3-[4-(4-chlorophenyl)cyclohexyl]-4-hydroxy-1,2-naphthalenedione

208. Cis -2-(4-(4-chlorophenyl)cyclohexyl)-3-hydroxynaphthalene-1,4-dione

2.4 Create Date
2005-03-28
3 Chemical and Physical Properties
Molecular Weight 366.8 g/mol
Molecular Formula C22H19ClO3
XLogP35.2
Hydrogen Bond Donor Count1
Hydrogen Bond Acceptor Count3
Rotatable Bond Count2
Exact Mass366.1022722 g/mol
Monoisotopic Mass366.1022722 g/mol
Topological Polar Surface Area54.4 Ų
Heavy Atom Count26
Formal Charge0
Complexity595
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 Drug Information
1 of 4  
Drug NameAtovaquone
PubMed HealthAtovaquone (By mouth)
Drug ClassesAntiprotozoal
Drug LabelAtovaquone is an antiprotozoal agent. The chemical name of atovaquone is trans-2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthalenedione. Atovaquone is a yellow crystalline solid that is practically insoluble in water. It has a molecular weight...
Active IngredientAtovaquone
Dosage FormSuspension
RouteOral
Strength750mg/5ml
Market StatusPrescription
CompanyAmneal Pharms

2 of 4  
Drug NameMepron
PubMed HealthAtovaquone (By mouth)
Drug ClassesAntiprotozoal
Drug LabelMEPRON (atovaquone) is an antiprotozoal agent. The chemical name of atovaquone is trans-2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthalenedione. Atovaquone is a yellow crystalline solid that is practically insoluble in water. It has a molecul...
Active IngredientAtovaquone
Dosage FormSuspension
RouteOral
Strength750mg/5ml
Market StatusPrescription
CompanyGlaxosmithkline

3 of 4  
Drug NameAtovaquone
PubMed HealthAtovaquone (By mouth)
Drug ClassesAntiprotozoal
Drug LabelAtovaquone is an antiprotozoal agent. The chemical name of atovaquone is trans-2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthalenedione. Atovaquone is a yellow crystalline solid that is practically insoluble in water. It has a molecular weight...
Active IngredientAtovaquone
Dosage FormSuspension
RouteOral
Strength750mg/5ml
Market StatusPrescription
CompanyAmneal Pharms

4 of 4  
Drug NameMepron
PubMed HealthAtovaquone (By mouth)
Drug ClassesAntiprotozoal
Drug LabelMEPRON (atovaquone) is an antiprotozoal agent. The chemical name of atovaquone is trans-2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthalenedione. Atovaquone is a yellow crystalline solid that is practically insoluble in water. It has a molecul...
Active IngredientAtovaquone
Dosage FormSuspension
RouteOral
Strength750mg/5ml
Market StatusPrescription
CompanyGlaxosmithkline

4.2 Therapeutic Uses

Antipneumocystic

O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. 13th Edition, Whitehouse Station, NJ: Merck and Co., Inc., 2001., p. 149


A tablet containing a fixed dose of 250 mg of atovaquone and 100 mg of proguanil hydrochloride, taken orally, has been highly effective and safe in a 3-day regimen for treating mild to moderate attacks of chloroquine- and multidrug-resistant falciparum malaria.

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. 1076


Atovaquone is indicated in the treatment of mild to moderate Pneumocystis carinii pneumonia (A-a gradient < or = 45 mmHg and pO2 > or = 60 mmHg on room air) in patients who are intolerant of sulfamethoxazole and trimethoprim combination. /Included in US product labeling/

MICROMEDEX Thomson Health Care. USPDI - Drug Information for the Health Care Professional. 22nd ed. Volume 1. MICROMEDEX Thomson Health Care, Greenwood Village, CO. 2002. Content Reviewed and Approved by the U.S. Pharmacopeial Convention, Inc., p. 502


Atovaquone is indicated in the prevention of Pneumocystis carinii pneumonia in patients who are intolerant of sulfamethoxazole and trimethoprim combination. /Included in US product labeling/

MICROMEDEX Thomson Health Care. USPDI - Drug Information for the Health Care Professional. 22nd ed. Volume 1. MICROMEDEX Thomson Health Care, Greenwood Village, CO. 2002. Content Reviewed and Approved by the U.S. Pharmacopeial Convention, Inc., p. 502


For more Therapeutic Uses (Complete) data for ATOVAQUONE (18 total), please visit the HSDB record page.


4.3 Drug Warning

Patients should be advised regarding pulmonary manifestations of possibly concurrent bacterial, viral, fungal, or mycobacterial infections associated with HIV infection and/or progression of the underlying Pneumocystis carinii pneumonia and to contact a clinician if pulmonary symptomatology develops or worsens during atovaquone therapy. Clinical deterioration during atovaquone therapy could represent secondary infection with a nonsusceptible pathogen and/or progression of the underlying P. carinii pneumonia. All patients for whom atovaquone therapy is being considered should be evaluated carefully for other possible causes of pulmonary disease and treated with additional agents as appropriate.

McEvoy, G.K. (ed.). American Hospital Formulary Service- Drug Information 2002. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2002 (Plus Supplements)., p. 846


Fever was reported in up to 40% of patients receiving atovaquone in controlled clinical trials and occasionally has required discontinuance of the drug. Oral candidiasis was reported in 10%, cough in 25%, sweating in 10%, sinusitis in 7%, and rhinitis in 24% of patients receiving atovaquone in controlled clinical trials. Infection of dyspnea has occurred in 22 or 15% of patients receiving atovaquone. Hypotension, vortex keratopathy, transient sinus arrhythmia, increased serum creatine kinase (CK, creatine phosphokinase, CPK) concentrations, and transient conjunctivitis also have been reported rarely.

McEvoy, G.K. (ed.). American Hospital Formulary Service- Drug Information 2002. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2002 (Plus Supplements)., p. 846


Hyperglycemia (exceeding 1.8 times the upper limit of normal) occurred in 9% of patients receiving atovaquone in controlled clinical trials. Hypoglycemia has occurred rarely.

McEvoy, G.K. (ed.). American Hospital Formulary Service- Drug Information 2002. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2002 (Plus Supplements)., p. 846


Increased BUN and serum creatinine concentrations have been reported rarely in patients receiving atovaquone and occasionally have required discontinuance of the drug. Hyponatremia (less than 0.96 times the lower limit of normal range) was reported in up to 10% of patients receiving atovaquone in controlled clinical trials. Acute renal impairment has occurred in patients receiving atovaquone.

McEvoy, G.K. (ed.). American Hospital Formulary Service- Drug Information 2002. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2002 (Plus Supplements)., p. 846


For more Drug Warnings (Complete) data for ATOVAQUONE (13 total), please visit the HSDB record page.


4.4 Drug Indication

For the treatment or prevention of Pneumocystis carinii pneumonia in patients who are intolerant to trimethoprim-sulfamethoxazole (TMP-SMX). Also indicated for the acute oral treatment of mild to moderate PCP in patients who are intolerant to TMP-SMX.


FDA Label


5 Pharmacology and Biochemistry
5.1 Pharmacology

Atovaquone is a highly lipophilic drug that closely resembles the structure [ubiquinone]. Its inhibitory effect being comparable to ubiquinone, atovaquone can act by selectively affecting mitochondrial electron transport and parallel processes such as ATP and pyrimidine biosynthesis in atovaquone-responsive parasites. Cytochrome bc1 complex (complex III) seems to serve as a highly discriminating molecular target for atovaquone in Plasmodia. There is no significant risk for myelosuppression associated with atovaquone, making this drug a beneficial therapeutic agent for recipients of bone marrow transplantation.


5.2 MeSH Pharmacological Classification

Anti-Infective Agents

Substances that prevent infectious agents or organisms from spreading or kill infectious agents in order to prevent the spread of infection. (See all compounds classified as Anti-Infective Agents.)


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.)


Antimalarials

Agents used in the treatment of malaria. They are usually classified on the basis of their action against plasmodia at different stages in their life cycle in the human. (From AMA, Drug Evaluations Annual, 1992, p1585) (See all compounds classified as Antimalarials.)


5.3 FDA Pharmacological Classification
5.3.1 Active Moiety
ATOVAQUONE
5.3.2 FDA UNII
Y883P1Z2LT
5.3.3 Pharmacological Classes
Antiprotozoal [EPC]; Antimalarial [EPC]
5.4 ATC Code

P01AX06

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


P - Antiparasitic products, insecticides and repellents

P01 - Antiprotozoals

P01A - Agents against amoebiasis and other protozoal diseases

P01AX - Other agents against amoebiasis and other protozoal diseases

P01AX06 - Atovaquone


5.5 Absorption, Distribution and Excretion

Absorption

The bioavailability of atovaquone is low and variable and is highly dependent on formulation and diet. Bioavailability of the suspension increases two-fold when administered with meals. When administered with food, bioavailability is approximately 47%. Without food, the bioavailability is 23%.


Route of Elimination

The half-life of atovaquone is long due to presumed enterohepatic cycling and eventual fecal elimination. There was little or no excretion of atovaquone in the urine (less than 0.6%).


Volume of Distribution

0.60 0.17 L/kg


Clearance

10.4 +/- 5.5 ml/min [HIV-infected patients receiving IV administration]


Drug absorption after a single oral dose is slow, erratic and variable; increased by 2- to 3-fold by fatty food; and dose-limited above 750 mg. More than 99% of the drug is bound to plasma protein, so its concentration in cerebrospinal fluid is less than 1% of that in plasma.

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. 1076


The bioavailability of atovaquone is low and variable, and decreases significantly with single doses greater than 750 mg. A standard breakfast containing 23 g of fat has been shown to enhance absorption significantly. Oral suspension: The oral suspension provides a two-fold increase in bioavailability in fasting or fed conditions compared to the tablets. Bioavailability of the suspension increases two-fold when administered with meals; when administered with food, bioavailability is approximately 47%. Tablets: Bioavailability increases three-fold when administered with meals; bioavailability of the tablets when administered with food is approximately 23%.

MICROMEDEX Thomson Health Care. USPDI - Drug Information for the Health Care Professional. 22nd ed. Volume 1. MICROMEDEX Thomson Health Care, Greenwood Village, CO. 2002. Content Reviewed and Approved by the U.S. Pharmacopeial Convention, Inc., p. 502


Fecal; > 94% of atovaquone was recovered in the feces over 21 days; < 0.6% was excreted in the urine.

MICROMEDEX Thomson Health Care. USPDI - Drug Information for the Health Care Professional. 22nd ed. Volume 1. MICROMEDEX Thomson Health Care, Greenwood Village, CO. 2002. Content Reviewed and Approved by the U.S. Pharmacopeial Convention, Inc., p. 503


Bioavailability is increased with meals. Time to peak blood level is 1 to 8 hours, with a second peak in 24 to 96 hours.

Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997., p. 268


For more Absorption, Distribution and Excretion (Complete) data for ATOVAQUONE (8 total), please visit the HSDB record page.


5.6 Metabolism/Metabolites

Some evidence suggests limited metabolism (although no metabolites have been identified).


Atovaquone is not significantly metabolized by human beings. It is excreted in bile and more than 94% of the drug is recovered unchanged in feces; only traces appear in the urine.

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. 1076


Atovaquone is an antiprotozoal compound with good in vitro stability against metabolic inactivation. Previous human studies which did not involve radiolabelling had not accounted for a substantial proportion of the dose. The possible metabolism of atovaquone in men was examined in a radiolabelling study involving four healthy male volunteers. Radioactivity was eliminated almost exclusively via the feces. All radioactivity in plasma, urine, and feces was accounted for by atovaquone, with no evidence of metabolites. Radiolabelled atovaquone was administered to a patient with an indwelling biliary tube after surgery. Biliary radioactivity was approximately 10- to 40-fold higher than that in plasma and was accounted for by atovaquone. Atovaquone is not significantly metabolized in humans but is excreted into bile against a high concentration gradient.

PMID:9174191 Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC163907 Rolan PE et al; Antimicrob Agents Chemother 41(6): 1319-1321 (1997)


5.7 Biological Half-Life

2.2 to 3.2 days


Atovaquone has a half-life averaging 1.5 to 3 days

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. 1076


2.2 to 3.2 days in adult patients with acquired immunodeficiency syndrome (AIDS), adult healthy volunteers, and immunocompromised children (ages 5 months to 13 years).

MICROMEDEX Thomson Health Care. USPDI - Drug Information for the Health Care Professional. 22nd ed. Volume 1. MICROMEDEX Thomson Health Care, Greenwood Village, CO. 2002. Content Reviewed and Approved by the U.S. Pharmacopeial Convention, Inc., p. 502


5.8 Mechanism of Action

The mechanism of action against Pneumocystis carinii has not been fully elucidated. In Plasmodium species, the site of action appears to be the cytochrome bc1 complex (Complex III). Several metabolic enzymes are linked to the mitochondrial electron transport chain via ubiquinone. Inhibition of electron transport by atovaquone will result in indirect inhibition of these enzymes. The ultimate metabolic effects of such blockade may include inhibition of nucleic acid and ATP synthesis. Atovaquone also has been shown to have good in vitro activity against Toxoplasma gondii.


Hydroxynaphthoquinone derivative that inhibits /parasitic/ mitochondrial electron transport.

O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. 13th Edition, Whitehouse Station, NJ: Merck and Co., Inc., 2001., p. 149


Atovaquone has possible cidal activity against susceptible organisms. The action against Pneumocystis carinii is not fully understood. Atovaquone is structurally similar to ubiquinone, which inhibits the mitochondrial electron-transport chain at the site of the cytochrome bc1 complex (complex III) in Plasmodium species. This may ultimately inhibit the synthesis of nucleic acid and ATP. Atovaquone also has been shown to have good in vitro activity against Toxoplasma gondii.

MICROMEDEX Thomson Health Care. USPDI - Drug Information for the Health Care Professional. 22nd ed. Volume 1. MICROMEDEX Thomson Health Care, Greenwood Village, CO. 2002. Content Reviewed and Approved by the U.S. Pharmacopeial Convention, Inc., p. 502


At present, approaches to studying mitochondrial functions in malarial parasites are quite limited because of the technical difficulties in isolating functional mitochondria in sufficient quantity and purity. We have developed a flow cytometric assay as an alternate means to study mitochondrial functions in intact erythrocytes infected with Plasmodium yoelii, a rodent malaria parasite. By using a very low concentration (2 nM) of a lipophilic cationic fluorescent probe, 3,3'dihexyloxacarbocyanine iodide, we were able to measure mitochondrial membrane potential(DeltaPsim) in live intact parasitized erythrocytes through flow cytometry. The accumulation of the probe into parasite mitochondria was dependent on the presence of a membrane potential since inclusion of carbonyl cyanide m-chlorophenylhydrazone, a protonophore, dissipated the membrane potential and abolished the probe accumulation. We tested the effect of standard mitochondrial inhibitors such as myxothiazole, antimycin, cyanide and rotenone. All of them except rotenone collapsed the DeltaPsim and inhibited respiration. The assay was validated by comparing the EC50 of these compounds for inhibiting DeltaPsim and respiration. This assay was used to investigate the effect of various antimalarial drugs such as chloroquine, tetracycline and a broad spectrum antiparasitic drug atovaquone. We observed that only atovaquone collapsed DeltaPsim and inhibited parasite respiration within minutes after drug treatment. Furthermore, atovaquone had no effect on mammalian DeltaPsim. This suggests that atovaquone, shown to inhibit mitochondrial electron transport, also depolarizes malarial mitochondria with consequent cellular damage and death.

PMID:9020100 Srivastava IK et al; J Biol Chem 272(7): 3961-3966 (1997)