A 44-year-old man presents to the clinic worried about his risk for bladder cancer. His best friend who worked with him as a painter for the past 20-years died recently after being diagnosed with transitional cell carcinoma. He is worried that their long and heavy cigarette smoking history might have contributed to his death. He also reports that he has been feeling down since his friend's death 2 months ago and has not been eating or sleeping as usual. He took time off from work but now is running past due on some of his bills. He feels like he is moving a lot slower than usual. He would like to stop smoking but feels like it's impossible with just his willpower. What side-effect is most likely if this patient were started on his appropriate pharmacotherapy?

Can treat overdose with sodium bicarbonate

Can cause restlessness at initiation or termination

Can cause sedation and weight gain

Can worsen uncontrolled hypertension

A 21-year-old female presents to her psychiatrist for ongoing management of major depressive disorder. She has previously tried cognitive behavioral therapy as well as selective serotonin reuptake inhibitors, but neither treatment has been very effective. She also states that she has been smoking two packs per day for the last three months and would like to stop smoking. Based on these concerns, her psychiatrist prescribes a medication that addresses both depression and smoking cessation. Which of the following if present, would be a contraindication for the drug that was most likely prescribed in this case?

Patient also takes monoamine oxidase inhibitors

An 18-year-old female visits your obstetrics clinic for her first prenatal checkup. It's her first month of pregnancy and other than morning sickness, she is feeling well. Upon inquiring about her past medical history, the patient admits that she used to be very fearful of weight gain and often used laxatives to lose weight. After getting therapy for this condition, she regained her normal body weight but continues to struggle with the disease occasionally. Given this history, how could her past condition affect the pregnancy?

Postpartum depression for mother

Medication-assisted treatment for USMLE Step 3: High-Yield Psychiatry Lessons

MAT Fundamentals - The Sobering Start

Integrates FDA-approved medications with counseling & behavioral therapies for substance use disorders (SUDs).
Primary Goals: ↓ cravings, ↓ withdrawal symptoms, and block euphoric effects from illicit substances.
A comprehensive bio-psycho-social approach, not just medication alone; improves treatment retention.

⭐ MAT is the standard of care for Opioid Use Disorder (OUD) and is proven to significantly reduce the risk of fatal overdose.

Opioid Use Disorder - The Opioid Opponents

Principle: Pure opioid antagonists that block μ-opioid receptors. Non-addictive, no euphoric effect.

Feature	Naltrexone	Naloxone
Primary Use	Relapse Prevention	Acute Overdose Reversal
Mechanism	Long-acting antagonist	Short-acting antagonist
Administration	Oral (ReVia), IM injectable (Vivitrol)	IV, IM, Intranasal (Narcan)
Key Point	Must be opioid-free 7-10 days prior	Short half-life; may need re-dosing
Side Effect	Hepatotoxicity risk	Precipitates withdrawal

⭐ Buprenorphine is co-formulated with naloxone (Suboxone) to deter misuse. When crushed and injected, the naloxone component precipitates immediate, severe withdrawal symptoms, negating the opioid effect.

Naltrexone: Biphasic Dose Response and Mechanisms

Alcohol Use Disorder - Uncorking the Meds

First-Line Agents:
- Naltrexone: A μ-opioid receptor antagonist that reduces alcohol craving and heavy drinking days. Can be given PO or as a long-acting IM injection. ⚠️ Contraindicated with current opioid use or in severe liver failure.
- Acamprosate (Campral): A glutamate modulator, thought to restore GABA/glutamate balance. Helps maintain abstinence. Ideal for patients with liver disease but requires abstinence at initiation.
Second-Line Agents:
- Disulfiram: Inhibits aldehyde dehydrogenase, causing an aversive acetaldehyde syndrome if alcohol is consumed. Requires strict adherence and high motivation.
- Topiramate/Gabapentin: Off-label options that can help reduce cravings and overall consumption.

⭐ Naltrexone can be initiated while a patient is still drinking. Acamprosate is started only after abstinence is achieved to help maintain it.

Tobacco Use Disorder - Clearing the Smoke

Varenicline (Chantix):
- MOA: α4β2 nicotinic receptor partial agonist; reduces cravings and withdrawal.
- Highest single-agent efficacy.
- SEs: Nausea, insomnia, neuropsychiatric symptoms (use with caution).
Bupropion (Zyban):
- MOA: Norepinephrine-dopamine reuptake inhibitor.
- Good choice for co-occurring depression.
- ⚠️ Contraindicated in patients with seizure disorders or eating disorders.
Nicotine Replacement Therapy (NRT):
- Forms: Patch, gum, lozenge, inhaler.
- Strategy: Combine long-acting (patch) with short-acting (e.g., gum) for breakthrough cravings.

⭐ Combination NRT (patch + short-acting form) and varenicline are the most effective FDA-approved smoking cessation treatments.

High‑Yield Points - ⚡ Biggest Takeaways

Opioid Use Disorder (OUD): Treat with methadone (long-acting agonist, QTc risk), buprenorphine (partial agonist, ceiling effect), or naltrexone (antagonist, risk of precipitated withdrawal).

Buprenorphine is often combined with naloxone to deter IV misuse and can be prescribed from an office.

Alcohol Use Disorder (AUD): Naltrexone is first-line to reduce cravings.

Acamprosate is also first-line for AUD, especially with liver disease.

Disulfiram is a second-line aversive agent.

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Medication-assisted treatment