Synthroid vs Celexa: side-by-side comparison
Synthroid (Hormones and Birth Control) and Celexa (Anti-Depressants) belong to different therapeutic classes and are rarely interchangeable. This page compares the medications' purposes, mechanisms and the situations where each is used.
| Property | Synthroid | Celexa |
|---|---|---|
| Active ingredient | Levothyroxine | Citalopram |
| Manufacturer | AbbVie | Forest Laboratories / AbbVie |
| Class | Hormones and Birth Control | Anti-Depressants |
| Strengths | 25mcg, 50mcg, 75mcg, 100mcg, 150mcg | 10mg, 20mg, 40mg |
| Forms | tablet | tablet |
What's the same
Synthroid and Celexa are used in very different patients, and the points in common are limited. The main shared element is that both meet regulatory standards for efficacy and safety and benefit from pharmacist oversight.
Key differences
Synthroid belongs to Hormones and Birth Control while Celexa belongs to Anti-Depressants. Indications, mechanisms and target populations differ. The comparison is most useful when a clinician has mentioned both medications and the patient wants to understand where each fits.
Mechanism and action
Synthroid: Levothyroxine replaces deficient endogenous thyroxine, which is converted in tissues to the active hormone triiodothyronine (T3) by deiodinase enzymes. Celexa: Citalopram selectively inhibits the serotonin reuptake transporter, increasing synaptic serotonin availability with limited affinity for noradrenaline transporters or other receptors.
When Synthroid is preferred
Synthroid is approved for hypothyroidism of any cause (Hashimoto thyroiditis, post-thyroidectomy, post-radioiodine, congenital), goitre and TSH suppression after differentiated thyroid cancer.
When Celexa is preferred
Celexa is approved for major depressive disorder.
Frequently asked questions
Is Synthroid or Celexa better? ▾
Synthroid and Celexa are not interchangeable — they treat different conditions. Asking which is "better" is meaningful only when a clinician has weighed both for the same specific clinical scenario.
Can I switch from Synthroid to Celexa? ▾
Switching between Synthroid and Celexa is rarely an appropriate decision since they belong to different classes and treat different conditions. The real question is usually whether the diagnosis calls for one medication or the other — which the prescriber resolves.
Do Synthroid and Celexa have the same side effects? ▾
No — they belong to different classes and have distinct side-effect profiles. Each medication has its own prescribing information.
More Synthroid comparisons
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.