A Phase 3 interventional study of tolvaptan and placebo matching tolvaptan in Hyponatremias, Water Intoxication and Inappropriate ADH Syndrome, sponsored by Otsuka Pharmaceutical Development & Commercialization, Inc.. Completed at 23 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-13.
Sponsored by Otsuka Pharmaceutical Development & Commercialization, Inc. (part of Otsuka Holdings Co., Ltd.) · Phase 3, Interventional, and Treatment
This study's purpose is to determine whether tolvaptan can safely and effectively return the body's balance of sodium and water toward normal, and to characterize and quantify the potential clinical benefits of this treatment.
Hyponatremia is defined as a serum sodium concentration below the lower limit of normal and is the most frequently encountered electrolyte abnormality in hospitalized patients. Generally speaking, most cases of hyponatremia are mild. However, as the serum sodium falls below 130 milliequivalents/liter (mEq/L), the possibility of significant morbidity and mortality increases, and most clinicians will initiate corrective therapy for serum sodium values approaching 130 mEq/L and lower. The reasons for treating hyponatremia relate both to the symptoms, which may be quite disturbing to patients, as well as to potential outcomes including permanent neurological damage and death. There is also growing awareness of the association between hyponatremia and increased mortality in patients with heart failure.A common theme underlying the occurrence of hyponatremia whether in the setting of congestive heart failure, hepatic failure with ascites, or the syndrome of inappropriate anti-diuretic hormone (SIADH) is the non-osmotic secretion of arginine vasopressin (AVP). The presence of excess AVP leads to fluid retention and hyponatremia. Agents that antagonize AVP, causing proportionally more water diuresis than solute excretion, could offer a significant treatment option for patients with hyponatremia, compared to fluid restriction alone. Treatment of hyponatremia, particularly in clinical settings such as decompensated congestive heart failure, is difficult as conventional diuretics cause neurohormonal activation and further stimulate the inappropriate release of vasopressin, leading to additional retention of free water and aggravation of hypoosmolality. Similarly, for cirrhosis with ascites and SIADH, conventional diuretics are either minimally effective or completely contraindicated. An alternative approach to symptom relief and treatment of hyponatremia may be the use of vasopressin antagonists, which increase free water clearance with proportionally less effect on sodium excretion. Tolvaptan is an oral vasopressin antagonist with relative affinity for the V2 receptor which has been shown to induce a diuresis with proportionally more free-water than sodium loss. The current study is being undertaken in order to evaluate whether tolvaptan, an oral AVP inhibitor, will be effective in correcting mild to moderate hyponatremia, and to elucidate the effect of this correction on the subject's well-being.
164 studies on the registry are indexed under Hyponatremia; 16 are open to participants now.
This study's enrollment of 205 is above the median of 60 across 98 interventional studies indexed under Hyponatremia.
Browse Hyponatremia studies →Otsuka Pharmaceutical Development & Commercialization, Inc. is the lead sponsor of 295 studies on the registry; 18 are open to participants now.
Of its 106 completed or terminated interventional studies of FDA-regulated products, 71 (67%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Child-Pugh class
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Tolvaptan 15 mg tablet taken orally once daily for up to 30 days. Dose titration to 30 mg and then 60 mg occurred if the participant's sodium level change from the previous day was \<5 mEq/L and ≤ 135 mEq/L. The dose could be decreased at the investigator's discretion.
Drug: tolvaptan
Placebo matching tolvaptan tablet taken orally once daily for up to 30 days.
Drug: placebo matching tolvaptan
Tolvaptan tablet taken orally once daily.
Placebo matching tolvaptan tablet taken orally once daily.
Plan to share: Yes — Anonymized Individual participant data (IPD) that underlie the results of this study will be shared with researchers to achieve aims pre-specified in a methodologically sound research proposal. Small studies with less than 25 participants are excluded from data sharing.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form
Time frame: Data will be available after marketing approval in global markets or beginning 1-3 years following article publication. There is no end date to the availability of the data.
Access criteria: Otsuka will share data on the Vivli data sharing platform which can be found here: https://vivli.org/ourmember/Otsuka/
Data sharing details ↗ · clinical-trials.otsuka.com
Ran from Apr 2003 to primary completion in Dec 2005, 32 months.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Studies of the drug tested here: Tolvaptan
Otsuka Pharmaceutical Development & Commercialization, Inc. →