CurrentNeighborhood Health Plan of Rhode IslandPolicy N/A

Dichlorphenamide (Keveyis) coverage for periodic paralysis

Defines initial and continuation authorization criteria, quantity limits, prescribing requirements, exclusionary conditions, and coverage duration for dichlorphenamide for members (Medicaid scope).

Policy Summary

PayerNeighborhood Health Plan of Rhode Island

PolicyDichlorphenamide (Keveyis) coverage for periodic paralysis

Policy CodePolicy N/A

Change Typeclarified

Effective DateAug 1, 2019

Next Review Date

Key ActionInitial authorization (2 months) requires documentation that all initial criteria are met including age ≥18, neurologist involvement, failure/intolerance/contraindication to acetazolamide, absence of listed contraindications, and diagnostic support for primary hypo- or hyperkalemic periodic paralysis.

SourceLink

POLICY UPDATE CHANGES

Policy lists reviews in 05/2020, 03/2021, 03/2022, 03/2023, 03/2024, 03/2025 and scope as Medicaid.

2Covered Indications (periodic paralysis subtypes)

200 mg/dayMaximum daily dose limit

2 monthsInitial authorization duration

12 monthsRenewal authorization duration

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Coverage Summary

Coverage stance: covered_with_criteria for Medicaid members. Dichlorphenamide (Keveyis) is covered for treatment of primary hypokalemic and primary hyperkalemic periodic paralysis when the specified prior authorization criteria are met. Initial authorization is limited to 2 months and renewal authorization may be granted for 12 months when continuation criteria are satisfied. The policy requires prescriber involvement by or in consultation with a neurologist, age ≥18 for initial approval, and adherence to the maximum daily dose of 200 mg. Status: CURRENT.

Key thresholds and quick facts

Maximum daily dose200 mg/day

Initial authorization2 months

Renewal authorization12 months

ScopeMedicaid

Medical Necessity Criteria

Initial Authorization (2 months)

An authorization of 2 months may be granted when all the following criteria are met:

ALL of the following

Patient is 18 years of age or older
Maximum daily dose does not exceed 200mg<=200 mg/day
Authorization limited to doses <= 200 mg/day
Medication is prescribed by, or in consultation with, a neurologist
No contraindicating conditions
- Patient does not have hepatic impairment
- Patient does not have metabolic acidosis
- Patient does not have severe pulmonary disease (e.g; severe COPD)
- Patient is not concomitantly taking high-dose aspirin (doses greater than 325mg/day)
Failure/intolerance to acetazolamide
- The patient has an inadequate treatment response to acetazolamide
- The patient has intolerance to acetazolamide
- The patient has a contraindication to acetazolamide
Diagnosis-specific support (ONE of the following sets must be met)
- Primary Hypokalemic Periodic Paralysis (support by at least one of the following)
  - ANY of the following
    Genetic test results supportive of primary hypokalemic periodic paralysis
    Patient has a family history of primary hypokalemic periodic paralysis
    ALL of the following
    Patient's attacks are associated with hypokalemia
    Andersen-Tawil syndrome and thyrotoxic periodic paralysis have been ruled out
- Primary Hyperkalemic Periodic Paralysis (support by at least one of the following)

Provider Actions

Prior Authorization

Initial prior authorization required

Initial authorization limited to 2 months requires documentation that all initial criteria are met including age >=18, neurologist involvement, contraindication/intolerance/failure of acetazolamide, absence of listed contraindications, and diagnostic support for primary hypo- or hyperkalemic periodic paralysis.

Age ≥ 18
Prescribed by or in consultation with a neurologist
Inadequate response, intolerance, or contraindication to acetazolamide
No hepatic impairment, metabolic acidosis, severe pulmonary disease, or high‑dose aspirin use
Diagnostic support for primary hypokalemic or hyperkalemic periodic paralysis

Prior Authorization

Renewal prior authorization required

Renewal authorization for 12 months requires documentation of ongoing neurologist prescriber involvement, continued diagnosis, absence of severe pulmonary disease/hepatic insufficiency, dose ≤ 200 mg/day, and evidence of positive clinical response (reduced frequency of paralysis).

Prescribed by or in consultation with a neurologist
Documented diagnosis of primary hyperkalemic or hypokalemic periodic paralysis (or related variant)
No severe pulmonary disease (e.g., severe COPD) and no hepatic insufficiency (e.g., Child‑Pugh examples)
Maximum daily dose ≤ 200 mg
Evidence of positive clinical response (reduced frequency of paralysis) and continued need for therapy

Documentation Required

Diagnostic support documentation

For initial authorization, provide genetic test results or family history or clinical evidence (electrolyte association and exclusion of Andersen‑Tawil and/or thyrotoxic periodic paralysis) depending on the periodic paralysis subtype.

Genetic test results supportive of the subtype
Family history of primary hypo- or hyperkalemic periodic paralysis
Clinical evidence: attacks associated with hypo- or hyperkalemia and exclusion of Andersen‑Tawil syndrome (and thyrotoxic periodic paralysis where specified)

Billing Rule

Quantity limit enforcement

Dispensing limited to the stated tablet-to-mg ratio (4 tablets per 50 mg) as the basis for quantity checks.

Tablet-to-mg ratio: 4 tablets per 50 mg
Dispensing and quantity verification are based on this ratio

Background and Evidence

Dichlorphenamide (Keveyis) is indicated in this policy for primary hypokalemic and primary hyperkalemic periodic paralysis. For initial authorization, patients must have failed, be intolerant to, or have a contraindication to acetazolamide. Diagnostic support is required: for hypokalemic periodic paralysis, one of genetic test results, a family history, or attacks associated with hypokalemia with exclusion of Andersen-Tawil syndrome and thyrotoxic periodic paralysis; for hyperkalemic periodic paralysis, one of genetic test results, family history, or attacks associated with hyperkalemia with exclusion of Andersen-Tawil syndrome. The policy references the Keveyis package insert (March 2025) as supporting evidence. Safety exclusions (hepatic impairment, metabolic acidosis, severe pulmonary disease, and high-dose aspirin use) must be absent for approval.

Definitions

Evidence / References

Revision History

2019-08-01effective_date

Effective Date 08/01/2019; no material clinical policy change noted

2020-05-01review

Policy review 05/2020; no material clinical policy change noted

2021-03-01review

Policy review 03/2021; no material clinical policy change noted

2022-03-01review

Policy review 03/2022; no material clinical policy change noted

2023-03-01review

Policy review 03/2023; no material clinical policy change noted

2024-03-01review

Policy review 03/2024; no material clinical policy change noted

2025-03-01reviewLatest

Policy review 03/2025; no material clinical policy change noted