The U.S. Food and Drug Administration, or FDA, has divided all prescription drugs into five categories based on harm to the fetus when used by pregnant women: Class A, B, C, D and X . These classes range from A, where there is no harm to the fetus in human studies, to X, where the medication should never be used in pregnant women because the risks to the fetus outweigh any benefit to the mother or fetus. Class C drugs show harm to fetuses in animal studies, but there are no adequate controlled human studies to confirm or deny this harm to fetuses in humans. Class C drugs are allowed to be taken by pregnant mothers if they need the medications. Some antidepressants are categorized as Class C.
SSRIs, SNRIs and NRIs
All selective serotonin reuptake inhibitors, or SSRIs, except for paroxetine, are categorized as Class C. These drugs include citalopram, sold as Celexa; fluoxetine, under the brand name Prozac; fluvoxamine, known as Luvox; sertraline, or Zoloft; and escitalopram, sold as Lexapro. Serotonin and norepinephrine reuptake inhibitors, or SNRIs, are also classified as Class C. These include venlafaxine, sold as Effexor; duloxetine, brand name Cymbalta; desvenlafaxine, commonly known as Pristiq; and milnacipram, brand name Ixel. Norepinephrine reuptake inhibitors, or NRIs, include atomoxetine, sold as Strattera; mazindol, brand names Mazanor and Sanorex; reboxetine, which is sold as Edronax; and viloxazine, or Vivalan. They are all Class C.
MAO Inhibitors
Monoamine oxidase inhibitors, MAOIs, block the enzyme that breaks down the neurotransmitters dopamine, serotonin and norepenephrine. MAOIs including isocarboxazid, brand name Marplan; moclobemide, sold as Aurorix and Manerix; phenelzine, commonly known as Nardil; selegiline, brand names Eldepryl and Emsam; and tranylcypromine, sold as Parnate, are classified as Class C.
Antidepressants in Other Classes
Paroxetine, brand name Paxil, is the only SSRI that is not Class C, as it is more toxic and is in Class D. Buproprion, marketed as Wellbutrin and Zyban, is an atypical antidepressant that is Class B. Tricyclic antidepressants, or TCAs, are Class A, but due to side effects are not used as much to treat depression.
References
- Antidepressants Facts: A Review of Pregnancy Outcome Following Exposure to Newer Antidepressants
- "Medication Safety in Pregnancy and Breastfeeding"; Gideon Koren; 2007
- "Understanding Your Moods When You're Expecting: Emotions, Mental Health, and Happiness"; Lucy J. Puryear; 2007
- GlaxoSmithKline: Paxil Prescribing Information
- Marplan: Full Prescribing Information
