Virginia Commonwealth University VCU Scholars Compass Theses and Dissertations Graduate School 1977 Interactions of Ethanol and Methadone Vijay Aggarwal Follow this and additional works at: https://scholarscompass.vcu.edu/etd Part of the Pharmacy and Pharmaceutical Sciences Commons © The Author Downloaded from https://scholarscompass.vcu.edu/etd/4332 This Thesis is brought to you for free and open access by the Graduate School at VCU Scholars Compass. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of VCU Scholars Compass. For more information, please contact [email protected]. INTERACTIONS OF ETHANOL AND METHADONE by Vijay Aggarwal B.A., Case Western Reserve University, 1970 Thesis submitted in partial fulfillment of the requirements for the Degree of Doctor of Philosophy in the Department of Pharmacology at the Medical College of Virginia Virginia Commonwealth University Richmond, Virginia December, 1977 ABSTRACT INTERACTIONS OF ETHANOL AND METHADONE Vijay Aggarwal, Ph.D. Medical College of Virginia - Virginia Commonwealth University, 1977. Major Professor: Dr. R. J. Bath The effects of ethanol administration on the antinociceptive activ- • ity, lethal properties and brain concentration of methadone, were inves­ tigated. The effect of ethanol on the antinociceptive activity of metha­ done was assessed by the hot-plate and tail-flick tests. Concentrations of methadone in the brain were detennined by the use of 3H-methadone as well as by gas liquid chromatographic analysis. The study showed that moderate doses of ethanol did not alter tail-flick or hot-plate response by themselves. However, when combined with methadone, ethanol produced a significant increase in the antinociceptive effectiveness of methadone as measured by both a decrease in the ED50 of methadone and by an in­ creased intensity and prolonged duration of methadone antinociception. Ethanol increased the antinociceptive activity of methadone in both naive and methadone-tolerant mice. This increased activity was not due to simple addition of subthreshold effects of ethanol nor was it due to an ethanol-mediated increase in whole brain·concentrations of methadone. It is hypothesized that the increased antinooiceptive activity was the re­ sult of an ethanol-mediated increase in central nervous system sensitiv� ity to the antinociceptive activity of methadone. 1 Ethanol pretreatment produced significantly 1 ower brain concentra­ tions of methadone compared to controls when methadone was administered subcutaneously. When both drugs were administered orally, ethanol ad­ ministration resulted in brain concentrations of methadone initially less than control and at later times greater than control. In both ethanol and water-pretreated mice there was an excellent correlation between the whole brain concentration of methadone and antinociceptive effect, but the antinoci cepti ve effect at any brain concentration of methadone was greater in ethanol-pretreated mice. Although ethanol produced signifi­ cant alterations in the brain concentration of methadone, the brain con­ centration of ethanol was generally not altered by methadone administra­ tion. Investigations of the excretion of methadone and its metabolites and the half-life of methadone in the brain failed to reveal any signif­ icant ethanol-induced alterations. A dose of ethanol which increased the antinociceptive activity of methadone did not alter the oral or subcutaneous LD50 of methadone, al­ though mice that died as a result of ethanol and methadone administra­ tion died at lower whole brain concentrations of methadone than those that died as a result of methadone alone. The LD50 of ethanol was sig­ nificantly decreased in mice maintained on a methadone dose of 100 mg/ kg/day. 2 This thesis by Vijay Aggarwal is accepted in its present form as satisfying the thesis requirement for the degree of . Doctor .of Philosophy Date: Approved: j If-.lffe.x . .1.7.?. 7.. • .9- • �: ..NJ:--! ... l�1:1.. )!1�:.. ff.??... ii To Bobbi iii CURRICULUM VITAE iv V ACKl�O\JLEDGEMENTS My appreciation is expressed to Dr. Raymond Bath, my advisor, for i1is encouragement and advice during these investigations. I also wish to thank Dr. Robert Blanke for his advice and counsel and Dr. William Dewey for his guidance and concern during the final stages of the preperation of this manuscript as well as for the use of his laboratory facil ites. Special thanks are Jue the many friends and members of my family whose support made it possible for me to undertake and complete this project. The efforts of Llavid Clark and Teresa James in typing this manuscript are gratefully acknowledged. Financial support \,as provided from the Toxicology Trainee position in the Bureau of Forensic Sciences, Commonwealth of Virginia. vi TABLE OF CONTENTS TITLE PAGE DEDICATION .iii CURRICULUM VITAE . iv ACKNOWLEDGEMENTS . vi TABLE OF CONTENTS . .vii LIST OF TABLES . ix LIST OF FIGURES . xi IJffRODUCTIOii . 1 A) Methadone 1 B) Ethanol 8 C) Ethanol and Other Drugs 12 D) Other Drugs and Methadone 17 E) Ethanol and Methadone 19 F) Present Study 22 MATERIALS AliD METHODS 24 A) Materials 24 B) Methods . 25 RESULTS . 41 A) Antinociceptive Activity of Ethanol . 41 B) Effect of Ethanol on Methadone Antinociception, 44 C) Effect of Ethanol on Methadone Distribution . 47 D) Correlation Between Brain Concentration of Methadone and Antinociceptive Effect . 54 vii E) Effect of Ethanol on the Time Course of Methadone Antinociception 56 F) Effect of Food Deprivation on Methadone Antinociception. 67 G) Effect of Methadone on the Concentration of 71 Ethanol H) Effects of Ethanol on the Excretion of Methadone Metabolites and on the Half-Life of Methadone in Brain 73 I) Effect of Ethanol on the Antinociceptive Activity of 1-Methadone and. Other Narcotics 80 J) Antagonism of the Tail-Flick Activity of Ethanol and Methadone by Nal oxone. 80 K) Effects of Ethanol in Methadone-Tolerant Mice. 85 L) Toxic Effects of Ethanol and Methadone 94 Combinations DISCUSSION 104 A) Antinoc.iceptive Activity of Ethanol and Methadone. 104 B) Effect of Ethanol on Brain Concentration of Methadone and Effect of Methadone on Brain Concentration of Ethanol . _116 C) Toxicity of Ethanol and Methadone Combinations . 122 SUMMARY . 125 REFERENCES 126 APPENDIX - Determination of Brain Methadone Based on GLC and Scintillation Counting . 140 APPENDIX II - Effect of Ethanol on Other Narcotics. 150 viii LIST OF TABLES Table l. Tail-Flick Activity of Ethanol in Rats . 42 Table 2. Tail-Flick Activity of Ethanol in Mice . 43 Table 3. Effect of Ethanol on Brain and Serum Methadone Concentration ............. 49 Table 4. The Effect of Ethanol on the Distribution of Methadone and Unconjugated Metabolites . 51 Table 5. Effect of Ethanol on Liver/Serum and Lung/Serum Methadone Ratios . 53 Table 6. Effect of Ethanol on Brain and Serum Methadone Concentrations ...... , . 63 Table 7. Comparison of Simultaneously Administered Ethanol With 90 Minute Ethanol Pretreatment . 64 Table 8. Effect of Ethanol on the Loss of Methadone From the Stomach . 68 Table 9. The Effect of Food Deprivation on Methadone Antinociception . 70 Table 10. Effect of Methadone on Ethanol Concentrations in Rats . 74 Table 11. Effect of Ethanol on Unconjugated Methadone Metabolites in Bile and Urine . ..... 75 Table 12. Effect of Ethanol on Methadone Metabolites in the Liver. 79 Table 13. Effect of Naloxone on the Tail-Flick Activity of Ethano 1 . 84 Table 1 4. Comparison of Areas Under Graphs of Methadone Concentration � Time and % MPE � Time. 93 Table 15. Absorption of Ethanol in Methadone-Tolerant Mice With Food and Water . , 96 Table 16. Brain Concentrations of Methadone in Methadone Deaths . 101 Table 17. LD50 of Ethanol in Methadone-Tolerant Mice . 103 ix Table 18. Summary of Dose-Response Experiments . 107 Table 19. Time Course of Alterations in Specific Activity ......... 144 Table 20. Changes in Specific Activity of 3H- Methadone . ....... 146 X LIST OF FIGURES Figure 1. Metabolism of Methadone 3 Figure 2. Procedure for the Determination of Radiolabeled Methadone . ' . 30 Figure 3. Procedure for the Determination of Methadone In Brain by Gas Liquid Chromatography . 34 Figure 4. The Effect of Ethanol on the Hot-Plate Activity of Methadone in ICR Mice . 45 Figure 5. The Effect of Ethanol Pretreatment on the Tail-Flick Activity of Methadone . 45 Figure 6 . The Effect of Ethanol on the Tail-Flick Activity of Methadone in Sprague Dawley Rats . 48 Figure 7. Correlation Between Brain Concentration of Methadone and Tail-Flick Activity . SE Figure 8. Effect of Ethanol on the Time Course of Tai1-F·1 ick Activity a�d the Concentration of Methadone in Brain (4 mg/kg, s.c.) . 57 Figure 9. Effect of Ethanol on Simultaneously Administered Methadone . 58 Figure 10. The Time Course of Methadone Tail-Flick Activity When Ethanol is Administered 60 Minutes prior to Testing . .59 Figure 11. The Effect of Ethanol on the Tail-Flick Activity of Simultaneously Administered Methadone . .61 Figure 12. Effect of Ethanol Administered Before Methadone .6 5 Figure 13. Effect of Ethanol Administered After Methadone. .69 Figure 14. The Effect of Methadone on Brain Concentration of Ethanol . 72 Figure 15. Whole Brain Half-Life of Methadone Following a 4 mg/kg, s.c. Dose in Naive Mice . 77 Figure 16. The Effect of Ethanol Pretreatment on the Tail-Flick Activity of l-Methactone . �l Figure 17. Antagonism of the Tail-Flick Activity of Ethanol and Methadone by Na 1oxone . �3 xi Figure 18. Development of Tolerance to Daily Doses of Methadone 20 mg/kg/day (p.o.) ..... 86 Figure 19. The Effect of Methadone on Body Weight and Locomotor Activity 20 mg/kg/day ...... Figure 20. The Effect of a Single 20 mg/kg Oral Dose of Methadone in Naive Mice . 89 Figure 21. Tail Flick Activity and Brain Methadone Levels in Toleqrnt Mice (40 mg/kg, p.a.) ...... 91 Figure 22. The Effec't of Ethanol and Methadone in Methadone- Tolerant Mice ...... ... ........ 92 Figure 23. Whole Brain Half-Life of Methadone Following a 20 mg/kg Oral Dose in Naive and Tolerant Mice .