The FNP exam tests mental health pharmacology more than candidates expect. About 10 to 15% of questions touch on depression, anxiety, ADHD, bipolar disorder, or substance use disorder. And in real practice, primary care providers prescribe the majority of psychotropic medications in the US.
You can't refer everything out. You have to know the basics cold.
Mental health pharmacology rewards systematic thinking. Match the medication class to the indication and the side effect profile to the patient.
SSRIs — The Workhorse
First-line for depression and most anxiety disorders. Most-tested members:
- Sertraline (Zoloft) — most prescribed; good for depression, anxiety, PTSD, OCD
- Fluoxetine (Prozac) — long half-life, good for non-adherent patients; FDA-approved for pediatric depression and OCD
- Escitalopram (Lexapro) — clean profile, good first choice for anxiety
- Citalopram (Celexa) — QTc prolongation at higher doses; max 40 mg adult, 20 mg in elderly
- Paroxetine (Paxil) — most sedating, more anticholinergic; AVOID in pregnancy (Category D)
Common side effects: GI upset (early, transient), sexual dysfunction, weight changes, insomnia or sedation depending on agent, headache.
Important: all SSRIs take 4 to 6 weeks for full effect. Don't switch or up-titrate too early.
Discontinuation syndrome: taper, don't stop abruptly. Worst with short-half-life drugs (paroxetine).
Serotonin syndrome: agitation, hyperreflexia, hyperthermia, autonomic instability when combined with other serotonergic drugs (tramadol, triptans, MAOIs, linezolid, St. John's Wort).
SNRIs
- Venlafaxine (Effexor) — depression, anxiety; can raise BP at higher doses
- Duloxetine (Cymbalta) — depression, anxiety, diabetic neuropathy, fibromyalgia
Atypical Antidepressants
- Bupropion (Wellbutrin) — no sexual side effects, helps smoking cessation. AVOID in seizure disorder, active eating disorder.
- Mirtazapine (Remeron) — sedating, increases appetite; useful in elderly with insomnia and weight loss.
- Trazodone — used off-label for sleep at low doses.
Tricyclics
Not first-line. Used for select indications: amitriptyline for neuropathic pain and migraine prophylaxis, nortriptyline for depression in older adults (less anticholinergic than amitriptyline). Cardiotoxic in overdose.
MAOIs
Rarely prescribed by FNPs. The exam wants you to recognize their dietary restrictions (tyramine-rich foods → hypertensive crisis) and serotonin syndrome risk with other agents.
Test Pearl: If a patient on an SSRI is admitted and started on tramadol or linezolid — serotonin syndrome is on the differential.
Anxiety Medications
- First-line for GAD: SSRI or SNRI. Buspirone is an alternative.
- Benzodiazepines: short-term use only. Risk of dependence, falls, cognitive impairment. Beers Criteria — avoid in elderly.
- Beta blockers (propranolol): situational anxiety (performance, public speaking).
- Hydroxyzine: non-addictive option for short-term anxiety.
ADHD
- Stimulants: methylphenidate, amphetamine salts. First-line. Side effects: appetite suppression, insomnia, increased BP/HR, growth concerns in children. Schedule II.
- Non-stimulants: atomoxetine (Strattera), guanfacine (Intuniv), clonidine. Slower onset, no abuse potential.
Bipolar Disorder
NPs in primary care don't typically initiate, but you'll co-manage:
- Lithium: narrow therapeutic range (0.6–1.2). Monitor levels, renal function, thyroid. Toxicity: tremor, confusion, seizures.
- Valproate: hepatotoxicity, weight gain, alopecia. AVOID in pregnancy.
- Lamotrigine: requires slow titration to prevent Stevens-Johnson syndrome.
- NEVER give an SSRI as monotherapy to a bipolar patient — risk of inducing mania.
Substance Use Disorders
- Alcohol: Naltrexone, acamprosate, disulfiram.
- Opioid use disorder: Buprenorphine/naloxone (Suboxone), methadone, naltrexone.
- Tobacco: Varenicline (Chantix), bupropion, nicotine replacement.
Screening Tools to Know
- PHQ-9 — depression
- GAD-7 — generalized anxiety
- AUDIT — alcohol
- CAGE — alcohol (4 questions)
- SBIRT — Screening, Brief Intervention, Referral to Treatment
- PCL-5 — PTSD
- Columbia Suicide Severity Rating Scale — suicide risk
What Trips Candidates Up
- Forgetting that SSRIs need 4 to 6 weeks for effect.
- Adding bupropion to a patient with bulimia or seizures.
- Picking paroxetine for a pregnant patient.
- Starting an SSRI in a known bipolar patient without a mood stabilizer.
- Not screening for suicide before prescribing antidepressants.
Build the framework. Match patient to class to specific drug. This section becomes manageable.