2025 Pain Reviews Find Oral Ketamine Evidence Depends on the Clinical Setting

Two systematic reviews published in 2025 examined oral ketamine for pain and reached a shared practical message: the clinical setting matters. Evidence from a short procedure should not be treated as interchangeable with evidence for long-term chronic pain, and an oral route does not settle questions about effectiveness or tolerability. Read the broader oral and sublingual ketamine review.

A review spanning several pain settings

The Journal of Pharmacy Practice and Research review, published in January 2025, included 21 studies. All assessed oral ketamine, and one compared oral with sublingual ketamine. Twelve investigated procedural pain, two postoperative pain, and five chronic pain; the remaining studies addressed dose comparison or route comparison. The abstract details the included settings.

Ten of the 12 procedural-pain studies found oral ketamine significantly better than the comparator for reducing procedural pain. Both postoperative studies found reduced need for additional analgesia compared with placebo. In contrast, the chronic pain findings were heterogeneous rather than uniformly favorable. See the results by pain category.

Those distinctions are central to the story. A summary saying only that most studies were positive would obscure the fact that most studies addressed procedures rather than persistent pain management.

A second review selected six randomized studies

A review published in the Journal of Pain & Palliative Care Pharmacotherapy in April 2025 selected six randomized studies after searching PubMed, CINAHL, and Web of Science through December 19, 2023. It examined oral ketamine for pain management and assessed study quality using the ROB2 risk-of-bias tool. Read the methods and selection summary.

Three studies comparing oral ketamine with other analgesics found no differences between groups. Two compared it with placebo: one reported reduced local-anesthetic use and intraoperative pain, while the other found no difference. Adverse reactions were common, but their severity was not reported. The review reports these efficacy and safety findings.

Why the study counts differ

The reviews should not be treated as if they were identical searches that reached competing verdicts on exactly the same data. They report different scopes and study selections. Understanding those methodological differences requires examining inclusion criteria, comparators, and the clinical settings being combined.

A larger study count alone does not settle which review is more applicable to a particular patient. A smaller review is not automatically more precise, either. The relevant question is whether the included studies match the treatment decision under discussion.

Chronic pain remains the harder claim

The six-study review characterized evidence for selected patients with refractory chronic neuropathic pain as preliminary and called for additional high-quality studies. That is a narrower conclusion than saying oral ketamine is an established treatment for chronic pain generally. Read the authors’ conclusion.

The broader review’s heterogeneous chronic pain findings reinforce the need to identify the actual diagnosis and outcome. Chronic pain is not one uniform study population, and a result concerning additional analgesic use during surgery does not answer whether someone’s daily function will improve months later.

Safety reporting is part of the evidence

The finding that adverse reactions were common but not graded for severity limits interpretation. It does not establish that reactions were mild, and it does not quantify the risks of indefinite treatment. Missing safety detail should remain visible rather than being filled in with reassurance. See the review’s adverse-reaction reporting.

For clinicians and patients, that points toward explicit monitoring plans, review dates, and an agreed response if harms outweigh benefits. Those are treatment-planning questions rather than outcomes the reviews themselves resolve.

What the findings mean for coverage

• Identify whether the research concerns procedural, postoperative, or chronic pain.
• State what the comparison treatment was.
• Distinguish symptom ratings from reduced rescue-medication use.
• Do not equate oral administration with established long-term safety.
• Keep preliminary conclusions labeled as preliminary.

The 2025 reviews add structure to a frequently oversimplified debate. They do not support a blanket claim that oral ketamine works for all pain—or that it never helps. They show a varied evidence base in which the patient population, treatment setting, comparator, and safety reporting determine how much a finding can reasonably tell us.

Sources

• Journal of Pharmacy Practice and Research: Oral and sublingual ketamine systematic review and meta-analysis
• Journal of Pain & Palliative Care Pharmacotherapy: Oral ketamine systematic review of randomized trials