A prospective intervention study on the effects of zinc treatment on patients with olfactory dysfunction associated with hypozincemia
Verification of the effect of zinc supplements on olfactory disorders caused by zinc deficiency
Tanaka Hirotaka
Department of Otorhinolarynogology
3-19-18 Nishishimbashi, Minato-ku, Tokyo
+81-3-3433-1111
s0363147@gmail.com
Tanaka Hirotaka
Department of Otorhinolarynogology
3-19-18 Nishishimbashi, Minato-ku, Tokyo
+81-3-3433-1111
s0363147@gmail.com
Recruiting
Sept. 01, 2025
Dec. 09, 2025
100
Interventional
single arm study
open(masking not used)
uncontrolled control
single assignment
treatment purpose
(1) Subjects whose serum zinc level was less than 80microgram/dL in a blood test prior to study participation (at their first otolaryngology visit).
(2) Subjects whose olfactory impairment was diagnosed as post-cold dysosmia, traumatic dysosmia, or idiopathic dysosmia according to the Guidelines for the Treatment of Olfactory Disorders.
(3) Age: Subjects aged 18 years or older and younger than 75 years at the time of consent.
(4) Gender: Any gender.
(5) Subjects who have received a full explanation of this study and, after fully understanding it, have given their voluntary written consent.
(6) Subjects who are able to make outpatient visits according to the study schedule.
(1) Individuals with a cognitive threshold of 1.0 or lower on a baseline olfactory acuity test conducted prior to study participation.
(2) Individuals diagnosed with an olfactory disorder due to air conduction olfactory impairment (e.g., rhinosinusitis), olfactory impairment associated with neurodegenerative disease, postoperative olfactory impairment, olfactory impairment associated with psychiatric illness, or congenital olfactory impairment.
(3) Individuals with severe liver, kidney, or cardiovascular disease (CTCAE ver. 5.0 Grade 2 or higher).
(4) Individuals already taking zinc supplements at the time of blood testing prior to study participation and unable to discontinue zinc supplements due to their current illness.
However, this does not apply if the following drug discontinuation criteria are met:
1. Individuals already taking zinc supplements (Promac tablets, Polaprezinc OD tablets, Nobelzin tablets, or zinc acetate tablets) prior to study participation will be required to undergo a one-month drug-withdrawal period followed by a repeat blood test and olfactory assessment. If the participation criteria are met, participants will be eligible to participate in the study. Although drug suspension may worsen the symptoms of zinc deficiency, zinc preparations will be resumed after participation in the study, so this is a relatively short period and serious symptoms are unlikely to occur.
2. If patients are taking antibiotics (tetracyclines, quinolones, cefdinir) before participating in the study, blood tests and olfactory tests will be conducted again one month after the last dose of the antibiotics. If the participation criteria are met, they will be able to participate in the study. For antibiotic treatment for typical acute infections, drug suspension is not expected to result in a recurrence of symptoms if the treatment is effective. However, patients who must take antibiotics chronically due to a known illness will not be suspended from medication and will not be able to participate in this study.
3. If patients are taking prohibited concomitant medications other than those listed above before participating in the study, drug suspension may cause a relapse of the known illness, so they will not be suspended from medication and will not be able to participate in this study.
(5) Subjects with malignant tumors
(6) Subjects with low serum copper levels in blood tests prior to study participation (CTCAE ver. 5.0 Grade 2 or higher)
(7) Subjects diagnosed with moderate or severe anemia (CTCAE ver. 5.0 Grade 2 or higher (Hb 10.0-8.0 g/dL) or higher)
(8) Subjects with a history of gastric ulcers
(9) Subjects with a history of anaphylactic shock or severe adverse reactions to zinc preparations
(10) Subjects who are or may be pregnant
(11) Subjects who are breastfeeding
(12) Subjects who the principal investigator or researchers deem inappropriate for participation in this study
18age old over
75age old not
Both
Post-viral, posttraumatic, and idiopahtic olfactory dysfunction with hypozincemia
Dosage of Zintas tablets based on serum zinc levels
Olfaction Disorder
D000857
Correlation between serum zinc levels at the first checkpoint and the rate of change in baseline olfactory acuity test between the start of study treatment and the first checkpoint
* Rate of change in baseline olfactory acuity test ((test value at start - test value at first checkpoint) / value at start x 100)
(1) Correlation between serum zinc levels at the second checkpoint and the rate of change in baseline olfactory acuity testing between the first and second checkpoints.
* Rate of change in baseline olfactory acuity testing ((test value at first checkpoint - test value at second checkpoint) / test value at first checkpoint x 100)
(2) Evaluation of the change in baseline olfactory acuity testing between the checkpoint at which zinc normalized and the final checkpoint in patients whose serum zinc levels normalized at the first and second checkpoints and who completed study treatment.
(3) Analysis of the relationship between improvement in baseline olfactory acuity testing at the first and second checkpoints and serum zinc levels at the first and second checkpoints.
* Based on the olfactory disorder improvement criteria established by the Olfaction Test Review Committee of the Japanese Rhinologic Society, which uses the mean cognitive threshold value of the baseline olfactory acuity testing, patients whose test results after treatment were "cured" or "relieved" were considered improved, and patients whose test results were "worsened" or "unchanged" were considered unimproved.
* The olfactory acuity testing improvement criteria were evaluated based on the difference in baseline olfactory acuity testing between the start of study treatment and each checkpoint.
Jikei University School of Medicine Clinical Research Review Committee
