Tranexamic Acid for Heavy Periods: Why Kidney Function Changes the Dose

A lower tranexamic acid schedule may reflect kidney function: the US tablet label requires reduced dosing when serum creatinine exceeds 1.4 mg/dL. Confirm your prescription before copying an online dose.¹

Why kidney function changes the schedule

Tranexamic acid leaves the body mainly through the kidneys. The US label reports that more than 95% is excreted unchanged in urine and provides reduced schedules for impaired kidney function. It still limits menstrual use to a maximum of five days.¹

Its kidney data describe 28 patients given one intravenous injection, with less medicine excreted as kidney function declined. This was not an oral heavy-period treatment trial. The label says renal-impairment pharmacokinetics have not been studied, but still requires lower dosing.¹

Have the prescriber apply the tablet dosing table. Another person’s schedule cannot settle yours.

Creatinine and eGFR are different entries

A lab report may show both serum creatinine and estimated glomerular filtration rate, or eGFR. NIDDK² explains that creatinine comes from normal muscle breakdown; the kidneys remove it, and clinicians use its blood concentration to estimate kidney filtration.²

NIDDK² describes kidney assessment using a blood filtration test and a urine albumin test. A urine albumin-to-creatinine ratio is another result with a different purpose. Do not substitute its number, or your eGFR number, into a medicine table headed serum creatinine. Bring the report with its test names, units and date.¹²

Ask which result the prescriber used and whether they need a newer test. This article cannot determine your kidney function or calculate a prescription from one number.

Tell the pharmacist before the next course

UK NHS³ guidance specifically asks people to disclose kidney problems before taking tranexamic acid. Pharmacy availability does not remove that check: the NHS says adults 18 and older can buy it from a pharmacy for heavy periods, while also listing conditions that can make it unsuitable. That availability statement applies to the UK.³

The same guidance asks about previous blood clots, epilepsy, pregnancy plans and irregular periods. Kidney-adjusted dosing addresses only one part of suitability. Tell the pharmacist if the bleeding pattern has changed rather than assuming another course is appropriate.³

The play

Try this: match the packet to the plan

1. Put the medicine packet and kidney lab report beside each other. Ask the pharmacist to confirm the tablet strength, tablets per dose and doses per day on your prescription.
2. Ask: “Was this schedule chosen because of my kidney function, and which test result did you use?” Request clarification before changing it.
3. Write the agreed start and stop instructions with your period notes. Keep the lab date and prescription date so the next review uses the same documents.

Record the bleeding response separately

Period, Handled, Chapter 11, explains how to keep a Period Scorecard and bring it to treatment discussions. Record bleeding changes there while keeping the prescribed medicine schedule alongside it. The Scorecard helps describe response; it does not calculate a kidney-adjusted dose. See the book.