Inclusion Criteria:

- Diagnosed with ALS, PMA or PLS based on the El Escorial ALS Diagnostic Criteria or
based on more recently revised Gold Coast ALS diagnostic criteria

- Experiences at least one muscle cramp in any muscle per day

- Age 20 to 70 years old

- Forced vital capacity is 45% of normal or greater in a seated position

- Able to swallow liquid via the mouth or be given via a feeding tube

- Caregiver available to assist with speaking or writing on behalf of the participant if
they are not able to speak or write due to the disease

- Able to comprehend and willing to give (sign) the informed consent

- Willing to commute to the study site for the frequent visits, including a screening
visit (study visits at the end of week 2, 5, 8 and 11)

- Taking a stable dose of Riluzole (Rilutek), Edaravone (RADICAVA), or both for at least
a month before randomization and not expected to require dose titration or initiation
of these medications during the study period

- Willing to discontinue over-the-counter (OTC) products containing any peony root,
Glycyrrhiza, or both

- Willing to discontinue Mexiletine, Quinine sulfate, or Ranolazine during the study
period

- Willing to avoid food, beverages, and medications that may induce or inhibit
metabolism of enzyme of transporters.

- Willing to refrain from initiation or dose adjustment of baclofen, gabapentin,
pregabalin, and/or memantine during the study period (stable dosing of these
medications is allowed).

- Willing to practice contraceptive measures for male and female patients.

Exclusion Criteria:

- History of allergic reactions to peony root, Glycyrrhiza, or FD&C Yellow No. 5
(tartrazine)

- Takes any medication known to increase the risk of pseudoaldosteronism or hypokalemia,
including corticosteroids and diuretics (except potassium sparing diuretics, such as
spironolactone or amiloride)

- History of pseudoaldosteronism or hypokalemia or current use of potassium
supplementation

- Screening potassium level 3.4 mEq/L or less

- Screening diastolic blood pressure (DBP) more than 90 mmHg or systolic blood pressure
(SBP) more than 150 mmHg after sufficient rest

- Screening albumin below normal laboratory level either at the Columbia or Mayo Clinic
Jacksonville laboratory

- Screening bicarbonate or carbon dioxide level less than 19 mmol/L, suggesting
metabolic alkalosis

- Screening sodium level greater than 145 mmol/L, suggesting hypernatremia

- Unstable or active medical or neurological (other than ALS) diseases which require
treatment

- Failure of Capacity Assessment

- Not able and/or willing to comprehend and sign the informed consent

- Not able to speak or write English to complete the primary outcome measure, MCS

- Taking any experimental medication or unapproved medications directed at treating
muscle cramps

- Those who are pregnant or breast feeding

- Those who have renal or hepatic impairment

Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Eligibility last updated 2/28/23. Questions regarding updates should be directed to the study team contact.