Hydroxychloroquine Therapy in Mixed Connective Tissue Disease

Pre-Treatment Requirements

A baseline electrocardiogram is mandatory to screen for QT prolongation, as hydroxychloroquine can cause cardiac conduction abnormalities including QRS widening and T-wave changes, according to the American College of Chest Physicians 1, 2
A comprehensive ophthalmologic examination using multifocal electroretinography and spectral domain optical coherence tomography is necessary to rule out pre-existing macular disease, as recommended by the Mayo Clinic 3
Renal function assessment is required, as hydroxychloroquine is 95% renally excreted and dose reduction may be necessary with impaired renal function, according to the American College of Chest Physicians 1

The standard dose of hydroxychloroquine is 200 mg twice daily (400 mg/day total) for MCTD, as recommended by the Mayo Clinic 3
The dose should not exceed 5 mg/kg actual body weight, as doses exceeding 250 mg/day significantly increase the risk of irreversible retinopathy and ototoxicity, according to the American College of Chest Physicians 1, 2

A baseline ophthalmologic examination is required before initiation, and annual screening should begin immediately in patients aged 65 years or older, using newer testing modalities such as multifocal electroretinography and spectral domain optical coherence tomography, as recommended by the Mayo Clinic 3, 2
Yearly ECG is necessary to monitor for cardiac conduction abnormalities, according to the American College of Chest Physicians 1, 2
Monitoring for drug interactions, particularly with cimetidine and D-penicillamine, which increase hydroxychloroquine levels, is required, as recommended by the American College of Chest Physicians 1, 2

The NP must ensure that the state practice act permits independent prescribing of DMARDs, according to the American College of Chest Physicians 1
The NP should have the ability to order and interpret required baseline and monitoring studies, as recommended by the Pulmonology journal 4
An established referral pathway to ophthalmology and rheumatology for complications is necessary, according to the Mayo Clinic 3

Hydroxychloroquine alone may be insufficient in patients with severe musculoskeletal involvement, interstitial lung disease, pulmonary arterial hypertension, or systemic sclerosis phenotype, and referral to rheumatology for consideration of mycophenolate, azathioprine, rituximab, or other immunosuppressants may be necessary, as recommended by the Arthritis and Rheumatology journal 5
Mycophenolate is preferred first-line for MCTD-ILD, according to the Arthritis and Rheumatology journal 5
In patients with systemic sclerosis phenotype, more aggressive therapy may be required, as recommended by the Pulmonology journal 4