Is Hydroxychloroquine (Plaquenil) an Immunosuppressant?

Hydroxychloroquine (Plaquenil) Increases the Risk of Shingles.

Hydroxychloroquine (Plaquenil) is an oral medication that is commonly used in the treatment of many types of autoimmune conditions including lichen planopilairs, frontal fibrosing alopecia, discoid lupus and pseudopelade. I’m often asked if hydroxychloroquine is an immunosuppressant or best classified as an immunomodulatory drug.

Hydroxychloroquine (Plaquenil) Is an Immunosuppressant.

In my opinion, Plaquenil is best considered an immunosuppressant. It’s true that it’s different than other immunosuppressants like methotrexate or cyclosporine. It does not seem to predispose to cancer development but does predispose to some infections. Two studies have shown that shingles (herpes zoster) is increased in hydroxychloroquine users. That’s where we’ll turn to today.

Liao TL et al, 2017

In 2017, Liao and colleagues set out to determine the risk factors and outcomes of herpes zoster (shingles) among patients with RA. The researchers found that exposure to Plaquenil was associated with a two fold increased risk of developing shingles (aOR=1.95, 95% CI 1.39 to 2.73, p<0.001)). Other immunosuppressants were also associated with an increased risk including corticosteroids (≥10 mg/day adjusted OR (aOR)=2.30, 95% CI 1.25 to 4.22, p=0.01), anti-tumour necrosis factor biologicals (aOR=2.07, 95% CI 1.34 to 3.19, p=0.001) and conventional synthetic disease-modifying anti-rheumatic drugs (methotrexate (aOR=1.98, 95% CI 1.43 to 2.76, p<0.001). To read the paper yourself, simply click on the link below.

Hu SC et al, 2016

In 2016 another study by Hu and colleagues published in the Journal of the American academy of Dermatology set out to address a similar question. Rather than studying rheumatoid arthritis patients, the researchers evaluated the risk of zoster (shingles) in patients with lupus (SLE) treated with different immunosuppressants. The authors found that hydroxychloroquine use did increase the risk of shingles. In fact, the risk was dependent on dose with patients using higher doses having slightly higher risk of shingles. Other medications associated with greater herpes zoster (shingles) risk in patients with SLE included oral corticosteroids, intravenous methylprednisolone, oral cyclophosphamide, intravenous cyclophosphamide, azathioprine, methotrexate, and mycophenolate mofetil.

Conclusion

Hydroxychloroquine (Plaquenil) appears to increase the risk of shingles in patients with Rheumatoid arthritis and patients with lupus. Whether it increases the risk in patients with scarring alopecia has not been studied but there is no reason to believe it should not. By virtue of affecting the risk of shingles, it would seem quite reasonable to classify hydroxychloroquine as a true immunosuppressant.

REFERENCE

Liao TL, et al. Risk and severity of herpes zoster in patients with rheumatoid arthritis receiving different immunosuppressive medications: a case-control study in Asia. BMJ Open. 2017.

Hu SC, et al. Immunosuppressive medication use and risk of herpes zoster (HZ) in patients with systemic lupus erythematosus (SLE): A nationwide case-control study. J Am Acad Dermatol. 2016.