Patients on stable doses of non-biologic DMARDs (e.g., methotrexate, sulfasalazine) without specific comorbidities (e.g., obesity, diabetes mellitus, renal disease, liver disease, alcohol use, concomitant use of hepatotoxic or myelosuppressive medications) are at a low overall risk of toxicity. More frequent blood draws pose an unnecessary burden to patients. Patients new to treatment, on escalating doses, or with abnormal baseline labs typically require more frequent monitoring.
Sources:
Hideto Kameda, Takao Fujii, Ayako Nakajima, Ryuji Koike, Akira Sagawa, Katsuaki Kanbe, Tetsuya Tomita, Masayoshi Harigai, Yasuo Suzuki & Japan College of Rheumatology subcommittee on the guideline for the use of methotrexate in patients with rheumatoid arthritis (2019) Japan College of Rheumatology guideline for the use of methotrexate in patients with rheumatoid arthritis, Modern Rheumatology, 29:1, 31-40, DOI: 10.1080/14397595.2018.1472358. PMID: 29718746.
Jo Ledingham, Nicola Gullick, Katherine Irving, Rachel Gorodkin, Melissa Aris, Jean Burke, Patrick Gordon, Dimitrios Christidis, Sarah Galloway, Eranga Hayes, Andrew Jeffries, Scott Mercer, Janice Mooney, Sander van Leuven, James Galloway, on behalf of the BSR and BHPR Standards, Guidelines and Audit Working Group, BSR and BHPR guideline for the prescription and monitoring of non-biologic disease-modifying anti-rheumatic drugs, Rheumatology, Volume 56, Issue 6, June 2017, Pages 865–868, https://doi.org/10.1093/rheumatology/kew479. PMID: 28339817.
Nakafero G, Grainge MJ, Card T, Mallen CD, Zhang W, Doherty M, Taal MW, Aithal GP, Abhishek A. What is the incidence of methotrexate or leflunomide discontinuation related to cytopenia, liver enzyme elevation or kidney function decline? Rheumatology (Oxford). 2021 Dec 1;60(12):5785-5794. doi: 10.1093/rheumatology/keab254. PMID: 33725120.
Singh JA, Saag KG, Bridges SL Jr, Akl EA, Bannuru RR, Sullivan MC, Vaysbrot E, McNaughton C, Osani M, Shmerling RH, Curtis JR, Furst DE, Parks D, Kavanaugh A, O’Dell J, King C, Leong A, Matteson EL, Schousboe JT, Drevlow B, Ginsberg S, Grober J, St Clair EW, Tindall E, Miller AS, McAlindon T. 2015 American College of Rheumatology Guideline for the Treatment of Rheumatoid Arthritis. Arthritis Rheumatol. 2016 Jan;68(1):1-26. doi: 10.1002/art.39480. Epub 2015 Nov 6. PMID: 26545940.
Yazici, Y et al. “Long term safety of methotrexate in routine clinical care: discontinuation is unusual and rarely the result of laboratory abnormalities.” Annals of the rheumatic diseases vol. 64,2 (2005): 207-11. doi:10.1136/ard.2004.023408. PMID: 15208176.