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Pharmacotherapy: From Antabuse to Zenova-vax

This presentation explores the use of pharmacotherapy in substance abuse treatment, focusing on the drugs Disulfiram (Antabuse) and the cocaine vaccine Zenova-vax. It discusses their mechanisms of action, effectiveness, and potential side effects. The presentation also highlights the role of dopamine and pharmacogenetics in substance abuse treatment.

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Pharmacotherapy: From Antabuse to Zenova-vax

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  1. APA PresentationSubstance Abuse Pharmacotherapy:From Antabuse to Zenova-vax Thomas Kosten MD Waggoner Chair and Professor of Psychiatry & Neuroscience, Baylor College of Medicine President – College on Problems of Drug Dependence Past President – American Academy of Addiction Psychiatry

  2. Outline of Presentation • Focus on Stimulants • Disulfiram (Antabuse) • Dopamine & pharmacogenetics • Cocaine vaccine (Zenova-vax) • Blocking cocaine entry into brain

  3. Receptor Sensitivity Sites of Drmcg Action at the Synapse Dopamine Normal Receptors Dopamine Reuptake Dopamine Dopamine Reuptake Overactivity Dopamine Receptor Receptor How Cocaine Alters the Brain:Dopamine Damage & Parkinsonism

  4. %ID/cc 0.030 0.015 0.000 Control Amphetamine Cocaine PD Parkinsonian (PD) Brain Abnormalities in Cocaine Abusers

  5. Hypodopaminergic State In Drmcg Addiction DA DA DA DA DA DA DA DA DA DA DA DA DA DA DA DA DA DA Reward Circuits Reward Circuits Non Drmcg Abuser Addicted Subject

  6. Dopamine Agonist TherapyReverse Craving and Attenuate Priming • Reverse stimulant induced dopamine deficiency – receptors down, transporters up • D2 agonists not effective – bromocriptine • Indirect agonists promising • Disulfiram: inhibit dopamine beta hydroxylase conversion of dopamine to norepinephrine

  7. Disulfiram increases dopamine (DA) by inhibiting its conversion to norepinephrine (NE) DA and NE-responsive Neuron Alpha 2 and DA1 receptors NE neuron Low DβH reduces DA to NE conversion Higher Dopamine (lower NE) forrelease

  8. Disulfiram Effects on Acute Cocaine (2mg/kg I.N.)Yellow (cocaine alone), Red (disulfiram + cocaine) Craving for cocaine Nervousness from cocaine

  9. Study (n) vs Naltrexone (18) w Buprenorphine (20) w Methadone (67) Psychotherapy (117) Match Study (115) Meta Average Disulfiram vs. Placebo % Cocaine Free Urines 90% vs 66% 41% vs 25% 35% vs 25% 55% vs 40% 57% vs 45% 55% vs 40% Cocaine Free Urines Across 5 Disulfiram Clinical Studies (n=337)

  10. Disulfiram vs. Placebo: Cocaine-free urinesHigh cocaine use group, stratified by DBH genotypePink line is disulfiram (n=75) (Schottenfeld 2004) TT + CT (lower DβH): CC (higher DβH):

  11. Conclusions for Disulfiram • Disulfiram increases cocaine-free urines more than placebo (55% vs 40%) • Individuals with genetically lower plasma DBH levels (CT and TT genotypes at –1021C>T) showed the best response to disulfiram. • Mechanism may be reduced craving, reduced withdrawal and increased cocaine-induced dysphoria

  12. Immunotherapy and Vaccines for Cocaine Dependence

  13. Capillary BloodFlow Brain Drugs of abuse easily enter the brain

  14. Capillary BloodFlow Brain Antibodies can reduce brain concentrations Antibody holds drugs in blood stream

  15. CocaineVaccine: What is it? • Active immunisation • Hapten: Cocaine derivative • Carrier protein: Cholera toxin B (rCTB) • Aluminium hydroxide adjuvant

  16. Cocaine bound to Cholera toxin rCTB cocaine derivative

  17. Effects of cocaine vaccine in animals • Vaccine generated antibodies can bind modest amounts of injected cocaine • NO animal toxicity. Even at several times a clinically relevant dose • Vaccine decreased cocaine self administration (SA) in rodents

  18. Safety of Vaccine & Cocaine Antibodies in Humans • Safety: no major adverse events: year FU • Injection events: temperature elevations (minimal), headache (10%), sore throat (6%) • Rise in antibody significant after third dose at week 4 and peaks after fifth (12 wk) dose. • Decline in antibody levels from peak evident by four months after initial vaccination and drops to undetectable after 9-12 months

  19. Cocaine Antibody (AB) rise with 3 months of dosing Five dosing schedules: 3 to 5 doses, 100, 400, 1000 mcg

  20. Fewer cocaine urines at higher Vaccine DoseVaccination makes antibodies by Week 4 (n=11) Z= -3.17, p=0.0015

  21. Less relapse to cocaine use with high vs low dose vaccination(Percent of patients relapsing in each dosage group)

  22. Human Laboratory Study Meg Haney – Columbia University • Determine direct relationship between plasma antibody levels and cocaine’s subjective and cardiovascular effects • Administer smoked cocaine (0, 25, 50 mg) to non-treatment seeking, cocaine-dependent research volunteers pre-vaccine and for 12 weeks post-vaccine

  23. Plasma Antibody (n=10) 2400 High Antibody Low Antibody 2100 1800 1500 Titer 1200 900 600 300 1 0 0 13 26 39 52 Weeks

  24. max = 100 Ratings (mm) ) S m o k e d C o c a i n e D o s e ( m g Good Drug Effect High AB Low AB 90 W e e k 3 13% 75 W e e k 1 3 23% 60 49% 45 30 79% 15 0 0 25 5 0 25 5 50 0 50

  25. W e e k 3 W e e k 1 3 Self-reported Cocaine Use Low AB High AB 175 150 125 Dollars/5 days 100 75 50 25 0

  26. Conclusions: Human cocaine administration • Current results encouraging: • Vaccine well tolerated; safe in combination with cocaine • Reliable antibody production: 50% volunteers • Those who produced antibody showed a substantial decrease in cocaine intoxication • Outpatient cocaine use reduced in those producing high antibody levels

  27. Outpatient cocaine vaccine RCT in methadone patients

  28. Cocaine Vaccine Study Design (methadone patients) • Double blind placebo-controlled randomised clinical trial • 114 methadone-maintained cocaine dependent patients • Vaccinated with 5 x 360 µg TA-CD over 12 weeks • Urine toxicology 3x/week • Serum antibody levels assessed at 0, 4, 8, 12 weeks

  29. Mean serum antibody levels (0-12 weeks)

  30. Promise of Stimulant Pharmacotherapies • Disulfiram reduces stimulant abuse perhaps by increasing dopamine available in brain and reducing norepinephrine • Pharmacogenetic matching of patients to disulfiram treatment shows promise • Newer treatments include cocaine vaccine with efficacy support from human cocaine administration and recent placebo RCT

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