Synthroid vs Xalatan: side-by-side comparison
Synthroid (Hormones and Birth Control) and Xalatan (Eye Care and Ophthalmic Treatments) 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 | Xalatan |
|---|---|---|
| Active ingredient | Levothyroxine | Latanoprost |
| Manufacturer | AbbVie | Pfizer |
| Class | Hormones and Birth Control | Eye Care and Ophthalmic Treatments |
| Strengths | 25mcg, 50mcg, 75mcg, 100mcg, 150mcg | 0.005% |
| Forms | tablet | ophthalmic solution |
What's the same
Synthroid and Xalatan 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 Xalatan belongs to Eye Care and Ophthalmic Treatments. 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. Xalatan: Latanoprost is a prodrug ester hydrolysed by corneal esterases to its active free acid, which selectively binds the prostaglandin F (FP) receptor.
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 Xalatan is preferred
Xalatan is approved in adults and children for the reduction of elevated intraocular pressure in patients with chronic open-angle glaucoma or ocular hypertension.
Frequently asked questions
Is Synthroid or Xalatan better? ▾
Synthroid and Xalatan 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 Xalatan? ▾
Switching between Synthroid and Xalatan 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 Xalatan 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.