Page 54 - Naplex Q&A 2025 Version

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Dose adjustments may be necessary in patients 84. (a) Methotrexate is classified as a folic acid
with concomitant use of: strong CYP1A2 inhibitors antagonist. It is indicated for the treatment of:
(e.g., fluvoxamine, ciprofloxacin, or enoxacin);
moderate or weak CYP1A2 inhibitors (e.g., oral 1. Gestational choriocarcinoma, chorioadenoma
contraceptives, or caffeine); CYP2D6 or CYP3A4 destruens and hydatidiform mole.
inhibitors (e.g., cimetidine, escitalopram,
erythromycin, paroxetine, bupropion, fluoxetine, 2. Breast cancer, epidermoid cancers of the head
quinidine, duloxetine, terbinafine, or sertraline); and neck, advanced mycosis fungoides (cutaneous T
CYP3A4 inducers (e.g., phenytoin, carbamazepine, cell lymphoma), and lung cancer, particularly
St. John’s wort, and rifampin); or CYP1A2 inducers squamous cell and small cell types.
(e.g., tobacco smoking).
3. Advanced stage non-Hodgkin's lymphomas.
Obtain a CBC, including the ANC value, prior to
initiating treatment with CLOZARIL to ensure the 4. In the symptomatic control of severe,
presence of a normal baseline neutrophil count recalcitrant, disabling psoriasis that is not
(equal to or greater than 1500/µL) and to permit adequately responsive to other forms of therapy.
later comparisons. Patients in the general
population with an ANC equal to or greater than (≥) 5. Rheumatoid arthritis and children with active
1500/µL are considered within normal range and polyarticular-course juvenile rheumatoid arthritis.
are eligible to initiate treatment.
It may cause hepatotoxicity, diarrhea, ulcerative
Weekly ANC monitoring is required for all patients colitis and stomatitis. It may produce marked bone
during the first 6 months of treatment. If a patient’s marrow suppression with anemia, leukopenia and
ANC remains equal to or greater than 1500/µL for thrombocytopenia.
the first 6 months of treatment, monitoring
frequency may be reduced to every 2 weeks for the It may raise the serum concentration of uric acid
next 6 months. If the ANC remains equal to or and therefore should be carefully used by patients
greater than 1500/µL for the second 6 months of suffering from gout.
continuous therapy, ANC monitoring frequency may
be reduced to once every 4 weeks thereafter. Probenecid may inhibit the renal excretion of
Methotrexate and thereby raise the serum
82. (a) Treatment with Clozaril should not be concentration of the drug and its toxicities. An
initiated if the patient’s ANC count is less than overdose of Methotrexate can be treated by the
1500/µL. use of Wellcovorin (Leucovorin calcium).

There are different levels of neutropenia: Periodic monitoring of CBC with differential,
platelet counts, and liver and renal function tests
1. Normal range: ≥ 1500/µL must be mandatory part of Methotrexate therapy.
2. Mild Neutropenia: 1000 to 1499/µL
3. Moderate Neutropenia: 500 to 999/µL 85.(e) Dyrenium (Triamterene), Trimpex
4. Severe Neutropenia: less than 500/µL (Trimethoprim), Trexall and Rheumatrex
(Methotrexate) and Daraprim (Pyrimethamine) are
83. (e) Thiazide diuretics, phenothiazines, folic acid antagonists.
tetracyclines and sulfonamides may increase the
sunlight sensitivity of skin. Patients who are taking Dyrenium (Triamterene) is a potassium sparing
these drugs for a prolonged period of time need to diuretic. It is indicated for the treatment of edema
avoid direct sunlight. associated with CHF, nephrotic syndrome and
hepatic cirrhosis.

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