Systemic Immunomodulators Flashcards
What is the mechanism of apremilast?
PDE-4 inhibitor
What are the indications for apremilast?
Psoriasis and psoriatic arthritis
What are the most common side effects of apremilast?
Diarrhea and nausea (usually go away spontaneously in 4 weeks)
What is a serious medical history item that should be screen for apremilast?
Depression/suicidality. There have been reports of depression on the medication
Renal adjustment of apremilast?
Yes, in severe renal impairment, halve the dose
Laboratory monitoring needed for apremilast?
None!
What JAK’s are affected by tofacitinib?
JAK 1 and 3
What are the most common side effects for JAK inhibitors?
URI, mild headaches, and nausea. May have decreased hgb and neutrophil count but normalizes on treatment.
Also may have increased LDL, HDL, CK, TGs, and LFTs
What JAK inhibitors are affected by Ruxolitinib?
JAK 1 and 2
What is azathioprine’s active metabolite?
6-TG (thioguanine)
What is azathioprine’s mechanism of action?
Active metabolite is produced by hypoxanthine-guanine phosphoribosyltransferase (HGPRT) pathway and shares similarities w/ endogenous purines. So, it gets incorporated in the DNA and RNA and inhibits purine metabolism and cell division. This is particularly true if the cells are fast-growing and don’t have a purine salvage pathway (like lymphocytes).
What enzymes break azathioprine into its inactive metabolites?
Xanthine oxidase and thiopurine methyltransferase
What is the clinical effect of azathioprine?
It diminishes T-cell unction and antibody production by B-cells
What medications can lead to life-threatening myelosuppression in people taking azathioprine?
Xanthine oxidase is involved in the conversion to inactive metabolites, so allopurinol or febuxostat can inhibit this and lead to elevated levels of azathioprine
What other medications besides allopurinol and febuxostat can increase the risk of myelosuppression with azathioprine?
ACEi, sulfasalzine, and concomitant use of folate antagonists
What test must be checked before starting azathioprine?
TPMT activty
Important side effects of azathioprine?
Leukopenia, thrombocytopenia, and immunosuppression (correlates with low TPMT activity)
What cancer risks are increased in azathioprine?
Squamous cell carcinoma and lymphoma (non-Hodgkin’s B-cell lymphoma)
No clear evidence that this actually occurs with doses used in dermatologic dz
What are the most common side effects of azathioprine?
Gastrointestinal side effects: nausea, vomiting, and diarrhea (often between first and tenth day of therapy), gastritis and pancreatitis
When does hypersensitivity syndrome usually occur?
Usually between first and fourth week of therapy and more common in those getting MTX or cyclosporin
What effect on the killed hepatitis B vaccine do azathioprine and prednisone have?
These have been shown to decrease the response of the vaccine
If azathioprine is given with a TNF-a inhibitor, what cancer is the person at risk for?
Increased risk of hepatosplenic T-cell lymphoma
What baseline tests should be done before starting azathioprine?
Pregnancy test, tuberculin skin test
What is the mechanism of action for mycophenolate mofetil?
Binds and inhibits inosine monophosphate dehydrogenase
This is an important enzyme for de novo synthesis of purines - which is essential in activated lymphocytes
What medications or things can decrease the absorption of mycophenolate mofetil?
Requires gastric acidity –> needed for cleavage into its active version
things like antacids, H2 blockers, PPI’s things that decrease acidity will decrease serum levels
What are absolute contraindications for mycophenolate mofetil?
Pregnancy and drug allergy
What is the risk of skin cancer or other cancers in those taking mycophenolate mofetil for dermatologic conditions?
Unknown, risk is increased in transplant patients but these patients often have more than one medication on board.
What are the most common side effects of mycophenolate mofetil?
Diarrhea, abdominal pain, nausea, and vomiting
What is the neutrophil dysplasia that can be seen with the administration of mycophenolate mofetil, and what can it signify?
Pseudo-Pelger-Juet anomaly = nuclear hypolobulation w/ a left shift. This may predict the development of neutropenia
What baseline tests should be performed for mycophenolate mofetil?
Baseline hepatitis B/C panel, tuberculosis screen, and pregnancy test
What lab monitoring should be done for patients on mycophenolate mofetil?
CBC/ w diff, CMP at baseline and then every 2-4 weeks after starting treatment or dose escalation and then every 2-3 months once the dose is stable
What is the mechanism of action for cyclosporine?
Forms a complex w/ cyclophilin, which inhibits calcineurin (intracellular enzyme), –> decrease in NFAT activity (this transcribes various cytokines, such as IL-2)
How does cyclosporine affect CD4 and CD8 cells?
Decreases IL-2 production leads to decreased numbers of CD4 and CD8 cells
What is the maximum dose for dermatologic disease for cyclosporine?
5 mg/kg and can be used continuously for up to 1 year (FDA, 2 years for worldwide consenses)
In what patients is cyclosporine contraindicated in?
Lymphoma, risk of progression
What are the two most noted side effects of cyclosporine?
Hypertension and nephrotoxicity
these are dose and duration dependant
How can kidney damage be avoided in using cyclosporin?
Not exceeding doses of 2.5-5mg/kg, not using for more than 1 year, and dose adjusting when creatine increases by 30%
Is HTN a reason to discontinue cyclosporine?
No, the HTN that develops is thought to be 2/2 renal vasoconstriction. When it occurs it can be controlled with blood pressure medications.
What are the preferred blood pressure medications for cyclosporine-induced HTN and why?
CCB’s like nifedipine and isradipine because these do not affect serum levels of cyclosporin
Important side effects of cyclosporine?
Increased risk of NMSC (other malignancies is unclear), hyperlipidemia, hypertrichosis, gingival hyperplasia, myalgia, paresthesia, tremors, malaise, hyperuricemia (can precipitate gout), hypomagnesemia and hyperkalemia
Bilirubin, uric acid, lipids, potassium (all of these go up)
For the main labs think BULK-UP
What should be done if Cr increases by more than 30% while on cyclosporine?
Re-check Cr levels. If it is still >30% then decrease dose by at least 1mg/kg for 4 weeks. Then re-check the Cr. If it <30% increase over baseline then therapy can be resumed. If Creatine does not drop then discontinue therapy. If the creatine returns to within 10% of baseline, cyclosporine can be resumed at a lower dose
What should be done if creatine levels increase by >50% while on cyclosporine?
Cyclosporine must be decreased until the Cr has returned to baseline
What baseline measurements/labs should be done prior to starting cyclosporine?
2 baseline blood pressure at least 1 day apart
2 baseline creatine values at least 1 day apart
Baseline: BUN, CBC, LFTs, fasting lipid profile, magnesium, potassium, and uric acid
Monitoring for cyclosporin?
Labs (CBC, CMP, lipids, uric acid, magnesium) and blood pressures should be checked every 2 weeks for the first 1-2 months then every 4-6 weeks with blood pressure checked at each visit (encourage pt to take a home log of blood pressures)
What is the mechanism of action for methotrexate?
Binds dihydrofolate reductase with more affinity than folic acid. This prevents dihydrofolate from being converted to tetrahydrofolate which is a required cofactor for purine synthesis. Ultimately this inhibits cell division
What medications can be given to reduce side effects or rescue the patient from adverse effects of methotrexate?
Leucovorin (folinic acid) or thymidine. Folinic acid is the naturally occurring version of folic acid (synthetic). Both of these decrease side effects
Does giving folate or folinic acid decrease the efficacy of methotrexate?
No!
At what cumulative doses of methotrexate is there concern for hepatic fibrosis and how is this assessed?
> 1.5-5g of methotrexate, especially with preexisting live dz like HCV, psoriasis, EtOH abuse, or those not getting folate (reduces the risk of LFT abnormalities by 76%).
Presence of cirrhosis is tested w/ liver biopsy for now
Absolute contraindications of methotrexate?
Pregnancy and lactation
What are the idiosyncratic adverse reactions of methotrexate?
Acute pneumonitis (rare), methotrexate must be stopped early or can be life-threatening
Pancytopenia: usually occurs early (4-6 months), and may be idiosyncratic