Effects of Isotretinoin on Smell

NCT07309341 | Recruiting DMC

• 2 other identifiers: ISO511161919B012412359
• Study Type: interventional
• Target: 54
• Locations: 1 country
• Sites: 1

Brief Summary

Isotretinoin is a common medicine used to treat moderate to severe acne. It often causes dryness of the skin and the inside of the nose. Because a normal sense of smell depends on a healthy nasal lining, this dryness may affect how well a person can smell. This study will examine whether isotretinoin treatment changes the sense of smell in adults with acne. Before starting isotretinoin, participants will complete a standardized smell test and two short questionnaires about nasal symptoms and quality of life (NOSE and SNOT-22). After at least 4 weeks of treatment, the same smell test and questionnaires will be repeated. By comparing results before and after treatment, the study will test the hypothesis that isotretinoin has a negative effect on olfactory function and may reduce patients' ability to smell.

Conditions

Smell Dysfunction

Keywords

olfaction; smell disfunction; isotretinoin

Outcome Measures

Primary Outcomes (1)

• Change in Olfactory Function Score

  Change in olfactory function from baseline to at least 4 weeks after initiation of oral isotretinoin therapy, measured using the Connecticut Chemosensory Clinical Research Center (CCCRC) smell test. The CCCRC test includes odor identification and odor discrimination components, and yields a composite score representing overall olfactory performance.

  Baseline and 4 weeks after starting isotretinoin treatment.

Study Arms (1)

Isotretinoin Treatment Group

EXPERIMENTAL

Participants in this arm will receive standard-of-care oral isotretinoin prescribed by the Dermatology Department for the treatment of acne vulgaris. The dosage and duration of isotretinoin therapy will follow routine clinical practice and will be determined by the treating dermatologist. Olfactory function and nasal symptom assessments will be performed before starting isotretinoin and after at least four weeks of treatment.

Drug: isotretinoin

Interventions

isotretinoin DRUG

Oral isotretinoin prescribed as standard-of-care treatment for acne vulgaris. The dosage, formulation, and duration of therapy will follow routine clinical practice and will be determined by the treating dermatologist based on the participant's clinical condition and body weight. Participants will typically receive daily oral isotretinoin for at least four weeks before the post-treatment assessments.

Isotretinoin Treatment Group

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Diagnosed with acne and scheduled to start oral isotretinoin as part of routine dermatology care
• Willing to participate and able to give informed consent
• Not currently smoking
• No history of allergic rhinitis, sinusitis, or active upper respiratory infection
• No medical condition known to affect the sense of smell

You may not qualify if:

• Younger than 18 years or older than 45 years
• Current cigarette smoking
• History of chronic sinonasal disease
• Any condition that would prevent completing the smell test
• Not willing to continue participation or withdrawal of consent at any time

Sponsors & Collaborators

• Uşak University: lead
• The Scientific and Technological Research Council of Turkey: collaborator

Study Sites (1)

Uşak University Faculty of Medicine

Uşak, Merkez, 64300, Turkey (Türkiye)

RECRUITING

MeSH Terms

Conditions

Olfaction Disorders; Anosmia

Interventions

Isotretinoin

Condition Hierarchy (Ancestors)

Sensation Disorders; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Retinoids; Carotenoids; Polyenes; Alkenes; Hydrocarbons, Acyclic; Hydrocarbons; Organic Chemicals; Cyclohexenes; Cyclohexanes; Cycloparaffins; Hydrocarbons, Alicyclic; Hydrocarbons, Cyclic; Terpenes; Pigments, Biological; Biological Factors

Central Study Contacts

Faruk Kadri Bakkal, MD, Asistant Professor

CONTACT

+905059242255; faruk.bakkal@usak.edu.tr

Neslihan Demirel Öğüt, MD, Associate Professor

CONTACT

neslihan.ogut@usak.edu.tr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Masking Details: The statistician responsible for analyzing the olfactory test scores and questionnaire data will be masked to the timepoint (baseline vs post-treatment) and participant information. Clinical investigators and participants are not masked.
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 15, 2025
• First Posted: December 30, 2025
• Study Start: June 1, 2025
• Primary Completion: March 1, 2026
• Study Completion (Estimated): June 1, 2026
• Last Updated: December 30, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)