Wednesday, 15 Aug 2018

You are here

Hydroxychloroquine Being Over-Dosed with New Guidelines?

Hydroxychloroquine (HCQ) retinopathy prevention guidelines have revised from ideal body weight (IBW)-based dosing to actual body weight (ABW)-based dosing; the question remains whether these have been adopted in clinical practice.

A database of nearly 21,000 new HCQ users from a UK general population database studied HCQ dosing and use between 2007 and 2016. Specifically they examined whether users were subjected to excess HCQ dosing per ophthalmology guidelines (defined by exceeding 6.5 mg/kg of IBW and 5.0 mg/kg of ABW).

Between 2007 and 2016, the frequency of excess HCQ dosing declined from 40% to 36% using IBW and 38% to 30% using ABW. Among these, 47% of women were more likely to be excess-dosed (multivariable OR 12.52; 95% CI 10.99–14.26) using IBW and 38% (multivariable OR 1.98; 95% CI,1.81–2.15) using ABW.

Applying IBW, 37% of normal and 44% of obese patients were excess-dosed; however, applying ABW, 53% of normal and 10% of obese patients were excess-dosed (multivariable ORs = 1.61 and 0.1 (reference = normal); both p < 0.01). Long-term HCQ users showed similar excess dosing.

In the UK, it appears that many HCQ users, especially women, may have excess HCQ dosing. Over half of normal-BMI individuals were excess-dosed according to the latest guidelines.

This either implies the need to adjust HCQ dosing using these guidelines, or to further study the consequences of these dosing strategies or develop more evidence-based dosing recommendations that will maintain patient safety while taking HCQ.

 

Disclosures: 
The author has no conflicts of interest to disclose related to this subject

Add new comment

More Like This

NSAID Use Around Conception Increases Miscarriage Risk

A study from the American Journal of Obstetrics & Gynecology analyzed pregnant women from the Kaiser Permanente healthcare system and compared newly pregnant women who took non-steroidal anti-inflammatory drugs or acetaminophen or neither showed that using NSAIDs around conception carried a more than four-fold higher risk of early miscarriage. (Citation source: http://bit.ly/2tqNWN6)

Could Measuring Drug Levels with TNF Treatment Hurt Your Patients?

Our colleagues in gastroenterology measure drug levels with certain biologics used in inflammatory bowel disease in order to increase the dose for optimal benefit if the patient has a low trough level (i.e. targeting drug level).

There have been GI trials with T2T with drug levels but they are not always suggesting that the strategy is superior to usual care. Also, this is really not a common practice in rheumatology.

Methotrexate Update

I was delighted to see that investigators presenting work at EULAR 2018 haven’t lost interest in our old friend methotrexate, with a number of abstracts examining issues of safety, dose and route of administration.

Low incidence of methotrexate induced liver abnormalities

Cancer Therapies Inducing Immune-Related Adverse Events (irAEs)

Recent shifts in the cancer treatment paradigm towards immune therapies has led to wide implementation of the novel immune check point inhibitors (ICI) in the treatment of multiple types of advanced cancer.

While being quite effective in oncology, these checkpoint inhibitors have led to the emergence of a quite unique spectrum of rheumatologic conditions presented under the umbrella of immune-related adverse events (irAEs).

Tobacco Associated Deaths in the USA

JAMA Internal Medicine reports that in the USA, those who smoke cigar, pipe, or cigarette have a significant overall  mortality risk, and a much highers cancer mortality risk compared to nonsmokers.

The National Longitudinal Mortality Study collected baseline survey data from 1985 through 2011 and included 357,420 participants reporting on their use of cigar, pipes, or cigarettes.