Monitoring Drug Levels Can Help Treatment Adherence

Given the risk of organ damage from prednisone treatment in systemic lupus erythematosus, the anti-malarial hydroxychloroquine has become an important alternative in the treatment of this auto-immune disease.

But as with any medicine regime, adherence to treatment can be less than ideal, according to Michelle Petri, M.D., the director of the Hopkins Lupus Center at the Johns Hopkins University School of Medicine. That makes regular monitoring of whole-blood hydroxychloroquine levels an important part of treatment.

In a study published online in October 2015 in The Journal of Rheumatology, Dr. Petri and her colleagues found that measuring hydroxychloroquine in whole blood at office visits and sending notifications to patients whose levels were suboptimal improved treatment adherence. At the beginning of the study, 44 percent of patients had low hydroxychloroquine levels (less than 500 ng/mL in whole blood), and nearly a third of those were not taking their medication at all. After three office visits that included counseling on the importance of medication adherence, 80 percent of patients in the study were in compliance with their treatment regimens.  

The same study found that, despite earlier recommendations from the American Academy of Ophthalmology, dosing to a patient's actual weight (rather than ideal weight) is still appropriate, even for obese or short-statured patients. [[{"type":"media","view_mode":"media_crop","fid":"49459","attributes":{"alt":" Michelle Petri, M.D.","class":"media-image media-image-right","id":"media_crop_9740581890656","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"5984","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"font-size: 13.008px; line-height: 1.538em; float: right;","title":" Michelle Petri, M.D.","typeof":"foaf:Image"}}]]

In a recent CME/CE-Certified Clinical Update, Petri and her colleagues described the current research on monitoring systemic lupus erythematosus patients both for medication adherence and for ophthalmological complications. While annual screening for retinopathy is standard practice, they wrote, there has been limited research on the specificity and sensitivity of various tests. 

Rheumatology Network spoke with Petri about what practicing rheumatologists need to know about treating with hydroxychloroquine.

RN: What is the major message you'd like rheumatologists to understand about monitoring drug levels in lupus?

Petri: In the general population, only 50 percent of patients take their medications. We need to accept that this is also true in systemic lupus erythematosus. Not taking hydroxychloroquine can have devastating long-term consequences.

RN: There has been controversy over whether to dose hydroxychloroquine based on ideal or actual body weight. What guidelines should patients consider when making dosing decisions?

Petri: Using hydroxychloroquine blood levels Durcan et. al. showed that ideal body weight was not the correct way to dose. The 2016 updated guidelines from Ophthalmology (Marmor et al) now seem to accept this.

We never increase above 400 mg, though, no matter how obese the patient is.

RN: What are the best practices for monitoring for retinopathy?

Petri: We stop [hydroxychloroquine] if there are progressive changes on monitoring such as OCT [optical coherence tomography] that our retina specialist is sure are due to [the drug]. We just increase monitoring if we are not sure, or if there is no proof of progression. There are no safe alternative medications - so stopping it makes the management of the patient much more difficult.

RN: Why is monitoring hydroxychloroquine level on a regular basis important, and what sort of improvements did you see when you incorporated regular monitoring in the clinic?

Petri: Within three visits over 80 percent of patients had good adherence, continuing to check periodically can identify those patients who are "forgetting" again.

RN: What reasons did you find that patients might not adhere to their hydroxychloroquine treatment?

Petri: Mostly it was not wanting to take medicines, but a few patients had been told it causes blindness and had been frightened.

RN: Are there any misconceptions about hydroxychloroquine you'd like to clear up?

Petri: In the United States, patients are usually monitored by ophthalmology. I have never had a patient go blind in over 40 years of prescribing it.

References:

CLINICAL UPDATE: The Role of Monitoring Drug Levels in Lupus

. Durcan L, Clarke WA, Magder LS, Petri M. "Hydroxychloroquine Blood Levels in Systemic Lupus Erythematosus: Clarifying Dosing Controversies and Improving Adherence." 

The Journal of Rheumatology

. 2015;42(11):2092-2097. 

doi:10.3899/jrheum.150379

.

Marmor MF, Kellner U, Lai TY, Melles RB, Mieler WF. "Recommendations on Screening for Chloroquine and Hydroxychloroquine Retinopathy (2016 Revision)." Ophthalmology. 2016;123(6):1386-1394. doi:10.1016/j.ophtha.2016.01.058.