DMARDs (Disease-modifying antirheumatic drugs ) is a category of otherwise unrelated drugs defined by their use in rheumatoid arthritis to slow down disease progression. The term is often used in contrast to nonsteroidal anti-inflammatory drug (which refers to agents that treat the inflammation but not the underlying cause) and steroids (which blunt the immune response but are insufficient to slow down the progression of the disease).
The term “antirheumatic” can be used in similar contexts, but without making a claim about an effect on the course. Other terms that have historically been used to refer to the same group of drugs are “remission-inducing drugs” (RIDs) and “slow-acting anti-rheumatic drugs” (SAARDs).
Types of DMARDs
DMARDs have been classified as
Synthetic (sDMARD)
Conventional synthetic and targeted synthetic DMARDs (csDMARDs and tsDMARDs, respectively)
- csDMARDs are the traditional drugs (such as methotrexate, sulfasalazine, leflunomide, hydroxychloroquine, gold salts)
- tsDMARDs are drugs that were developed to target a particular molecular structureB
Biological (bDMARD)
These can be further separated into original and biosimilar DMARDs (boDMARDs and bsDMARDs)
- bsDMARDs are those that have the same primary, secondary and tertiary structure as an original (boDMARD) and possess similar efficacy and safety as the original protein
| Drug | Mechanism | Type |
|---|---|---|
| abatacept | T-cell costimulatory signal inhibitor | bDMARD |
| adalimumab | TNF inhibitor | bDMARD |
| anakinra | IL-1 receptor antagonist | bDMARD |
| azathioprine | Purine synthesis inhibitor | unknown |
| chloroquine (anti-malarial) | Suppression of IL-1, induce apoptosis of inflammatory cells and decrease chemotaxis | unknown |
| ciclosporin (Cyclosporin A) | calcineurin inhibitor | unknown |
| D-penicillamine (seldom used today) | Reducing numbers of T-lymphocytes etc. | unknown |
| etanercept | decoy TNF receptor | bDMARD |
| golimumab | TNF inhibitor | bDMARD |
| gold salts (sodium aurothiomalate, auranofin) (seldom used today) | unknown | csDMARD |
| hydroxychloroquine (anti-malarial) | TNF-alpha, induce apoptosis of inflammatory cells and decrease chemotaxis | csDMARD |
| infliximab | TNF inhibitor | bDMARD |
| leflunomide | Pyrimidine synthesis inhibitor | csDMARD |
| methotrexate (MTX) | Purine metabolism inhibitor | csDMARD |
| minocycline | 5-LO inhibitor | unknown |
| rituximab | chimeric monoclonal antibody against CD20 on B-cell surface | bDMARD |
| sulfasalazine (SSZ) | Suppression of IL-1 & TNF-alpha, induce apoptosis of inflammatory cells and increase chemotactic factors | csDMARD |
| tocilizumab | IL-6 receptor antagonist | bDMARD |
| tofacitinib | kinase inhibitor | tsDMARD |
Traditional DMARDs
- Azathioprine (Azasan, Imuran, generic): Comes in tablet only; used most commonly in lupus. This drug depends on a specific enzyme to work and some people lack enough of this enzyme to make the drug effective. Your doctor will test your levels before prescribing azathioprine.
- Cyclophosphamide (generic only): Comes in capsule, tablet or infusion. Can be used in lupus in patients who do not respond to traditional therapy or who experience kidney damage.
- Cyclosporine (Neoral, Gengraf, Sandimmune, generic): Comes in capsule or syrup. This medicine is used sometimes for lupus in people who do not respond to other therapies.
- Hydroxychloroquine sulfate (Plaquenil, generic): Comes in tablet only. Antimalarial drugs are commonly used to treat rheumatoid arthritis and can help improve the skin lesions of lupus, and can hold off disease recurrence and prevent organ damage. Serious side effects for antimalarial drugs are rare.
- Leflunomide (Arava, generic): Comes as a pill taken once a day. People who cannot tolerate methotrexate may take leflunomide. It can also be taken in combination with methotrexate.
- Methotrexate (Rheumatrex, Trexall, Otrexup, Rasuvo, generic): This drug is taken once a week and comes in tablet or as a self-injectable. It is for adults with active RA and children with active juvenile idiopathic arthritis with more than one affected joint.
- Mycophenolate mofetil (CellCept, generic): Comes in tablet, capsule and as a self-injectable. This drug may be used in people whose RA does not respond to other therapies.
- Sulfasalazine (Azulfidine, Sulfazine, generic): Comes in regular or extended-release tablets. This drug is most commonly used in a triple therapy combination for RA (methotrexate, sulfasalazine, hydroxychloroquine).
Mechanism of Action of DMARDs
The class of DMARDs is extensive, and traditional DMARDs act via various mechanisms. They interfere in combinations of critical pathways in the inflammatory cascade. Methotrexate, for example, stimulates adenosine release from fibroblasts, reduces neutrophil adhesion, inhibits leukotriene B4 synthesis by neutrophils, inhibits local IL-1 production, reduces levels of IL-6 and IL-8, suppresses cell-mediated immunity, and inhibits synovial collagenase gene expression. Other medications in this class serve to inhibit proliferation or cause dysfunction of lymphocytes.
Biologics, on the other hand, are very selective in their mechanism of action. The overarching functional of biologics include (1) interfering with cytokine function or production, (2) inhibiting the “second signal” required for T-cell activation, and (3) depleting B-cells or inhibiting factors that active B-cells (rituximab and belimumab). Tofacitinib is a small molecule inhibitor of JAK, a protein tyrosine kinase involved in mediating cytokine signaling.
Contraindications of DMARDs
DMARDs are not to be taken by patients who have an active infection, those with preexisting bone marrow hypoplasia, leukopenia, chronic liver disease, or immunodeficiency syndromes. Methotrexate is contraindicated in pregnancy.
Monitoring
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Most DMARDs which cause myelosuppression and hepatotoxicity can be monitored with a complete blood count (CBC) and liver function tests every 2 weeks to monthly.
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Those that cause macular damage (hydroxychloroquine) should be monitored with funduscopic exams twice yearly.
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Cyclophosphamide, which can cause hemorrhagic cystitis and bladder cancer, can be monitored with a CBC and urinalysis every 2 weeks.
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Cyclosporine and FK506 (tacrolimus) can cause renal insufficiency, hypertension, and anemia and should be monitored with blood pressure and creatinine checks bi-monthly, along with periodic CBC, potassium levels, and liver enzymes.
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Biologics including etanercept and infliximab can allow for systemic infection as well as injection site infection. They can be monitored with PPD before initiating or re-starting therapy as well as periodic CBC.
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