Hematologic toxicity

Heptylphysostigmine (eptastigmine) (17) has been shown to be as active as physostigmine in AChE inhibition, but superior to physostigmine in terms of oral bioavadabihty and half-life (118—120). However, further clinical evaluation of this compound has been halted because of dmg-related hematological toxicity. 

Nitrogen mustard is clinically used for the treatment of lymphomas and some forms of lung cancer. The major indication for mechlorethamine is Hodgkin s disease as a part of the MOPP regimen (mechlorethamine + vincristine (oncovin) + procarbazine + prednisone). The usual dose consists of 6 mg/m2 on days 1 and 8. This drug has pronounced hematological toxicity (myelo-suppression). 

Rifabutin Adults0 5 mg/kg (300 mg) Children Appropriate dosing unknown Hematologic toxicity, uveitis, gastrointestinal symptoms, polyarthralgias, hepatotoxicity, pseudojaundice (skin discoloration with normal bilirubin), rash, flulike syndrome, orange discoloration of bodily fluids (sputum, urine, sweat, tears) Drug interactions are less problematic than rifampin... 

This hot antibody is linked to yttrium and binds to the CD20 receptor of B lymphocytes (see Rituximab below). Hematologic toxicity may occur several weeks after administration and may take weeks to resolve. 

When immunosuppressive therapy is administered for long periods, the patient must be monitored closely for chronic toxicity. Blood counts should be monitored routinely in patients on azathioprine because hematologic toxicity resulting in infection and bleeding may occur. Cushingoid effects, aseptic... 

The association between low TPMT activity and excessive hematological toxicity has been recognized [31, 35, 37]. Molecular analysis of the TPMT genotype is able to identify patients at risk for acute toxicity from thiopurines. A recent study involving 180 children identified that the TPMT genotype plays an important role in a patients tolerance to 6-MP therapy [51]. Two of the patients, who were TPMT-de-... 

The answer is c. (Hardman, pp 1134-1135.) Hematologic toxicity is by far the most important adverse effect of chloramphenicol The toxicity consists of two types (1) bone marrow depression (common) and (2) aplastic anemia (rare) Chloramphenicol can produce a potentially fatal toxic reaction, the gray baby syndrome, caused by diminished ability of neonates to conjugate chloramphenicol with resultant high serum concentrations. Tetracyclines produce staining of the teeth and phototoxicity... 

Oxaliplatin has a mechanism similar to that of cisplatin but, unlike other platinums, is associated with minimal renal toxicity, hematologic toxicity, and nausea and vomiting. 

Approximately 10% of new chemical entities (NCEs) show serious adverse drug reactions (ADRs) after market launch. Such events usually result in new black box warnings by the US Food and Drug Administration (FDA), label change or market withdrawal. The most common causes for these actions are hepatic toxicity, hematologic toxicity and cardiovascular toxicity [2], Reasons for such ADRs, which are identified only after NCEs are launched on the market, include the narrow spectrum of clinical disorders and participating patient profiles in clinical studies as well as the fact that serious ADRs are often rare and that the number of patient exposures required to identify such occurrences sometimes may range over a few millions [3],... 

Hematological toxicity 10 Neuropsychiatric effects/ abuse liability/dependency 12... 

In one study, 68 patients with rheumatic disease on AZA (2 to 3 mg/kg/d) were genotyped for TPMT and TPMT3A alleles. All patients were assessed for side effects from AZA, such as leukopenia, liver function abnormalities, and GI intolerance. Of these patients, 6 (9%) patients were heterozygous for TPMT3A, of whom 5 discontinued AZA within 4 weeks of starting the medication because of hematologic toxicity (48). In another study, 40 RA patients on AZA (0.7 to 1.4 mg/ kg/d) were genotyped for the TPMT alleles. Of the 40 patients, 6 discontinued... 

Other stndies have examined the association between the activity of TPMT and other enzymes in the pnrine pathway and AZA toxicity. In one stndy, TPMT, HPRT, 5 -nncleotidase, and pnrine nncleoside phosphorylase activity in the RBCs of 33 RA patients on AZA (dose of approximately 2mg/kg/d) and 66 controls was meas-nred. Compared to patients with normal TPMT activity, 14 RA patients with low (p = 0.004) and 7 patients with intermediate TPMT activity (RR 3.1) developed AZA toxicity(4d). None of the patients were genotyped. Another study measured TPMT activity in 3 RA patients who had experienced AZA-induced hematologic toxicity and 16 RA patients withont AZA toxicity. In this study, 2 patients with AZA-indnced hematologic toxicity were TPMT deficient, one partial and the other complete (50). Patients were not genotyped in either of these studies. 

TPMT 3C A719G Tyrosine to cystine 0.2-0.8 As above As above Hematologic toxicity... 

Thiopurine methyltransferase methylates 6-mercaptopurine, a commonly used treatment for childhood acute lymphocytic leukemia, reducing its conversion to the active form of the drug. Approximately 10% of patients have intermediate enzyme activity, and 0.3% are deficient for TPMT activity. Intermediate activity patients have a greater incidence of thiopurine toxicity, whereas TPMT-deficient patients have severe or fatal hematological toxicity from 6-mercaptopurine therapy. In one study, patients deficient for TPMT tolerated only 7% of a 2.5-yr mercaptopurine treatment regimen. Patients with intermediate TPMT activity tolerated 65% of total weeks of therapy and patients with normal TPMT activity tolerated 84% of total weeks of therapy (3). 

Zidovudine has been associated with hematologic toxicity, including neutropenia and severe anemia, particularly in patients with advanced human immunodeficiency (HIV) disease (see Warnings). Prolonged use of zidovudine has been associated with symptomatic myopathy. 

Hepatic function impairment- Because zidovudine is primarily eliminated by hepatic metabolism, a reduction in the daily dose may be necessary in these patients. Frequent monitoring for hematologic toxicities is advised. 

Zidovudine may result in hematologic toxicity (eg, neutropenia, severe anemia), especially in patients with advanced human immunodeficiency virus (HIV). 

Hematologic toxicity- Modify trimetrexate and leucovorin doses based on the worst hematologic toxicity according to the following table. If leucovorin is given orally, round up doses to the next higher 25 mg increment. 

Chronic immunosuppression with azathioprine increases the risk of neoplasia. Physicians using this drug should be familiar with this risk as well as with the mutagenic potential to men and women and with possible hematologic toxicities. 

Hematoiogic effects Severe leukopenia or thrombocytopenia, macrocytic anemia, severe bone marrow depression, and selective erythrocyte aplasia may occur in patients on azathioprine. Hematologic toxicities are dose-related, may occur late in the... 

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