Study to Evaluate the Influence of Hydrochlorothiazide on Dermal Photosensitivity and DNA Stability - a Pilot Study (HCTox Study)

NCT ID: NCT04654312

Last Updated: 2025-08-11

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE1
• Total Enrollment: 30 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2021-01-18
• Study Completion Date: 2021-07-22

Brief Summary

The clinical trial is designed as a national, prospective, single-center, double-blind, parallel group, randomized, controlled, interventional trial to investigate whether a therapy with HCT compared with placebo can affect dermal photosensitivity and DNA stability.

Detailed Description

Previously published retrospective analyses leading to the official warning about the use of hydrochlorothiazide (HCT).

The underlying pilot study examins, if the intake of HCT leads to increased dermal photosensitivity and in combination with UV-exposition to a DNA-damage of the skin.

Up until today, there is no prospective, randomized, placebo-controlled trial investigating the impact of HCT on dermal photosensitivity in greater detail. The pilot trial is designed as feasibility study to clarify the impact of HCT on dermal photosensitivity. This may facilitate evidence-based recommendations as to whether or not HCT increases the risk for skin cancer. Of note, HCT is one of most frequently prescribed drugs in Germany.

Conditions

Photosensitivity

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: OTHER
• Blinding Strategy: DOUBLE

Study Groups

Intervention

Intake of HCT 25 mg, 1 tablet/d for 15 days

Group Type: EXPERIMENTAL

Hydrochlorothiazide

Intervention Type: DRUG

Please see arm descriptions

Placebo

Intake of Placebo, 1 tablet/d for 15 days

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: DRUG

Please see arm descriptions

Interventions

Hydrochlorothiazide

Please see arm descriptions

Intervention Type: DRUG

Placebo

Please see arm descriptions

Intervention Type: DRUG

Other Intervention Names

HCT

Eligibility Criteria

Inclusion Criteria

1. The subject is willing and able to participate and provides written informed consent;

2. Healthy subjects with no concomitant medical conditions;

3. Age ≥ 18 years;

4. The subject is willing to take HCT 25 mg a day although not clinically indicated;

5. The subject is willing to undergo controlled UV-exposition although not clinically indicated;

6. Skin type I - IV.

Exclusion Criteria

1. History of any cardiac disease;

2. History of any dermatologic disease;

3. Renal insufficiency (eGFR <60 ml/min/1.73m²);

4. Intake of photosensitive substances, especially intake of HCT;

5. Frequent, above-average, UV exposition (naturally or artificially);

6. Known hypertension;

7. Known electrolyte disbalance;

8. Systolic blood pressure at baseline <100 mmHg;

9. Skin type V and VI;

10. History of severe diseases, which could endanger the safety of study participant;

11. Known unresolved history of alcohol dependency or drug abuse or any other kind of dependencies

12. Intake of any of the following medications or substances: Betablockers; nitrates; barbiturates; phenothiazines; tricyclic antidepressants; vasodilatory drugs; ACE-inhibitors; NSAIDs; salicylates; phenytoin; Insulin; oral antidiabetic drugs; vasoconstrictors; glycosides; substances lowering blood-urea levels; substances causing a Long-QT-Syndrome; chinidine; carbamazepine; cyclosporine; cholecalciferol; potassium salts; amantadine; allopurinol; methyldopa; cholestyramine; colestipol; other diuretics; lithium; cytostatic drugs;

13. Women in childbearing age and not using medically acceptable effective contraception refer to CTFG: The study population includes female of childbearing potential. Female of childbearing potential have to agree to comply with the applicable contraceptive requirements of the protocol for the duration of the study or having post-menopausal status or be permanently sterilized (at least 6 weeks post-sterilization). Highly effective contraception is defined as a contraceptive method with failure rate of less than 1 % per year when used consistently and correctly and when applicable, in accordance with the product label;

14. Subject is pregnant (e.g., positive ß-hCG test) or is breast feeding;

15. Hypersensitivity to the active substance, to HCT or any of its excipients.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Universität des Saarlandes

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Felix Mahfoud, MD

Role: PRINCIPAL_INVESTIGATOR

Saarland University Hospital

Locations

Saarland University Hospital

Homburg, Saarland, Germany

Countries

Germany

References

Gotzinger F, Hohl M, Lauder L, Millenaar D, Kunz M, Meyer MR, Ukena C, Lerche CM, Philipsen PA, Reichrath J, Bohm M, Mahfoud F. A randomized, placebo-controlled, trial to assess the photosensitizing, phototoxic and carcinogenic potential of hydrochlorothiazide in healthy volunteers. J Hypertens. 2023 Nov 1;41(11):1853-1862. doi: 10.1097/HJH.0000000000003558. Epub 2023 Sep 13.

Reference Type: RESULT

PMID: 37702559 (View on PubMed)

Related Links

https://www.bfarm.de/SharedDocs/Risikoinformationen/Pharmakovigilanz/DE/RHB/2018/rhb-hydrochlorothiazid.html

Hydrochlorothiazid - Risiko von nichtmelanozytärem Hautkrebs \[Basalzellkarzinom (Basaliom); Plattenepithelkarzinom der Haut (Spinaliom): Rote-Hand-Brief vom 17. Oktober 2018.

Other Identifiers

HCTox

Identifier Type: -

Identifier Source: org_study_id