Heartburn drug could ease painful sun sensitivity

NCT ID NCT05020184

First seen Jun 27, 2026 · Last updated Jun 30, 2026 · Updated 2 times

Summary

This Phase 2 trial tested whether oral cimetidine (Tagamet), a common heartburn drug, can reduce light sensitivity in people with erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP). These genetic conditions cause severe pain from sunlight exposure. The study enrolled 26 participants who took cimetidine or a placebo twice daily for several weeks. Researchers measured changes in protoporphyrin levels, time to pain symptoms in sunlight, and quality of life.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance

cimetidine (Tagamet)

What this could lead to

If it works, this could point toward a treatment to reduce painful light sensitivity in people with protoporphyria.

What could go wrong

This is a small Phase 2 trial with only 26 participants, so results may not apply to everyone. The drug may not lower protoporphyrin levels enough to improve symptoms.

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This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Conditions

The condition(s) this trial relates to.

erythropoietic protoporphyria photosensitivity disease X-linked erythropoietic protoporphyria

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

More trials for these conditions

Other studies related to the condition(s) this trial covers.

Contacts and locations

Locations

  • Atrium Health Wake Forest Baptist Medical Center

    Winston-Salem, North Carolina, 27157, United States

  • Massachusetts General Hospital

    Boston, Massachusetts, 02114, United States

  • University of Texas Medical Branch

    Galveston, Texas, 77555, United States