Raeschell Williams, PharmD, BCPS, BCPP
Clinical Pharmacist Practitioner, Mental Health 
South Texas Veterans Health Care System
San Antonio, TX

Dr. Williams is a graduate of the University of Virginia where she earned her BA in Psychology. She then relocated to Kentucky where she earned her PharmD and MPH degrees from the University of Kentucky Colleges of Pharmacy and Public Health, respectively. She then moved to San Antonio, TX, where she completed her PGY1 Pharmacy Practice and PGY2 Psychiatric Pharmacy residencies at the South Texas Veterans Health Care System. She currently works as a clinical pharmacist practitioner (CPP) at the South Texas Veterans Health Care System at the Domicilliary Residential Rehabilitation Treatment Program (DRRTP), focusing on residential substance use treatment. She is Board Certified in Pharmacotherapy and Psychiatric Pharmacy,and has experience in substances of abuse through her work in the Clinical Pharmacy Practice Office (CPPO) Substance Use Disorder Subject Matter Expert Workgroup along with her current practice role.

How do you start the conversation surrounding illicit or non-prescription drug use?

As with many things in life, honesty is the best policy. Some patients are very upfront with their substance use, while others may need more prying. When asking about substance use, I find it best to be as specific as possible. For example, if a patient is evasive when being questioned, I like to provide reference points for them to follow, such as saying “every day, three times per week, more or less than that” or “one joint/blunt, one bowl, how many grams.” The goal is to continue to ask questions until the patient gives a clear picture of their substance use. Additionally, patients may become more comfortable with providers after the initial meeting. Therefore, one may need to clarify at follow-up visits if there are any changes in substance use.

What substances are we talking about here?

There are many substances of abuse, but some of the most popular in recent times include marijuana, cannabidiols (CBD), synthetic cannabinoids, methamphetamine, cocaine, heroin, kratom, and xylazine.

  • Marijuana
    • Also known as cannabis
    • Contains two primary pharmaceutical cannabinoids, delta-9-tetrahydrocannabinol (∆-9-THC or THC) and CBD
    • THC is the primary psychoactive component of marijuana, leading to feelings of euphoria, as well as analgesic, antiemetic, anti-inflammatory, and antioxidant properties
  • CBD
    • Structurally similar to THC
    • Believed to be less psychoactive with its own health properties
    • CBD is believed to have antipsychotic, analgesic, anti-inflammatory, anxiolytic, and anticonvulsive properties
  • Synthetic cannabinoids
    • Thought to be more active at the cannabinoid receptors than THC
    • Most synthetic cannabinoids use a natural plant material which is then coated in synthetic cannabinoid that has been dissolved in a solvent, such as ethanol or acetone
    • Once the plant material dries, the solvent evaporates, leaving highly variable concentrations of chemicals
  • Methamphetamine
    • Central Nervous System (CNS) stimulant that may elevate mood, increase alertness, concentration, energy, and promote weight loss in low to moderate doses
    • In chronic, high-dose use, it can cause unpredictable and rapid mood changes, as well as psychosis
  • Cocaine
    • Derived from the leaves of the coca plant
    • Stimulant that may cause CNS stimulation, tachycardia, arrhythmias, and other cardiac effects with use
  • Heroin and kratom
    • Substances that act on the mu opioid receptor
    • Results in euphoric effects and altered mental status, along with sedation and respiratory depression
  • Xylazine
    • Alpha-2 agonist primarily used in veterinary medicine, which is being added to heroin, cocaine, fentanyl, and other illicit substances
    • Immediate effects include profound sedation, low blood pressure, bradycardia, and weak reflexes
    • Chronic effects include severe skin wounds (necrosis), anemia, blood sugar irregularities, and loss of autonomic tone, often seen as incontinence

What are the implications of substances of abuse in terms of drug-drug interactions (DDIs) or drug-disease state interactions?

DDIs between psychotropics and substances of abuse are primarily based on the mechanisms of action. For example, the stimulants (methamphetamine, cocaine) may cause worsening cardiac effects (hypertension, tachycardia) with MAOIs and TCAs. Antihypertensives and beta blockers are occasionally used to mitigate the cardiovascular toxicity of stimulants, however, there is no single agent to fully address the multifactorial cardiac toxicity of illicit stimulants. THC may cause sedation when combined with anticholinergics, and CNS depressants increase lithium concentration if used concurrently. Given the uncertainty surrounding synthetic cannabinoid composition, DDIs are varied, though there has been a rise in severe bleeding requiring hospitalizations with the use of synthetic cannabinoids which have been adulterated with anticoagulants.

Additionally, substances of abuse may exacerbate mental health concerns. For example, patients with histories of bipolar disorder or schizophrenia may notice worsening mood symptoms with use of illicit substances (worsening manic symptoms, worsening psychosis, etc.). This may especially be true for stimulants, hallucinogens, and adulterated substances. Additionally, not only can there be a worsening of mood symptoms, but use of substances of abuse may lead to DDIs noted above such that psychotropic medications may not work effectively, thus further exacerbating mood symptoms.

What harm reduction strategies can pharmacists utilize to address substance use?

As healthcare providers, our goal is to promote the health and wellbeing of our patients. This includes introducing and reviewing harm reductions strategies for our patients who use illicit substances. This may include discussing with patients about safe injection techniques, local needle exchange programs, naloxone dispensing and overdose education, and appropriate infectious disease testing. AAPP has compiled many resources, such as the AAPP Harm Reduction Guideline and Naloxone Access Guideline for Pharmacists, to assist pharmacists with addressing harm reduction strategies for patients who use illicit substances.

What resources are available?

AAPP Harm Reduction Guideline: https://aapp.org/guideline/harmreduction

Syringe Services Programs (SSPs): https://www.cdc.gov/ssp/index.html


  1. Substance Abuse and Mental Health Services Administration (SAMHSA) Opioid Overdose Prevention Toolkit: http://store.samhsa.gov/product/Opioid-Overdose-Prevention-Toolkit/SMA13-4742
  2. Community-based overdose prevention and naloxone distribution program locator: http://hopeandrecovery.org/locations/

Infectious Disease Testing:

  1. Hepatitis C:
    1. AAPP Pharmacist Toolkit for Hepatitis C: https://aapp.org/guideline/hepatitis-c
    2. https://www.cdc.gov/hepatitis/hcv/hcvfaq.htm#section3
  2. HIV: https://www.cdc.gov/hiv/clinicians/index.html