And appropriate dose

Allopurinol increases didanosine plasma concentrations and their coadministration is not recommended. Ganciclovir, tenofovir and disoproxil also increase didanosine plasma concentrations, and dose reduction is recommended. Conversely, methadone decreases didanosine plasma concentrations, and appropriate doses for the combination have not been established. Didanosine should not be administered with drugs that cause pancreatic or neurotoxicity. Ribavirin increases its risk of toxicity and should not be coadministered. 

The feeding study is expected to detect acute, life-threatening toxicity and to indicate the target organs and appropriate doses for longer-duratlon toxicology testing when results of the short-term tests indicate the need. 

Adverse reactions to -lactams (penicillins and cephalosporins) are not related to dose or blood concentrations. They are commonly administered in doses 10 to 100 times greater than necessary to inhibit organism growth, and appropriate dosing may be guided by susceptibility testing. Patient compliance and evaluation of patients with renal impairment are the most likely reasons to monitor the blood concentration. 

Transient elevations of the serum transaminases occur in 12% to 15% of patients receiving isoniazid and usually occur within the first 8 to 12 weeks of therapy. Overt hep ato toxicity, however, occurs in only 1% of cases. Risk factors for hepatotoxicity include patient age, preexisting liver disease, excessive alcohol intake, pregnancy, and the postpartum state. Isoniazid also may result in neurotoxicity, most frequently presenting as peripheral neuropathy or, in overdose, as seizures and coma. Patients with pyridox-ine deficiency, such as pregnant women, alcoholics, children, and the malnourished, are at increased risk. Isoniazid may inhibit the metabolism of phenytoin, carbamazepine, primidone, and warfarin." Patients who are being treated with these agents should be monitored closely, and appropriate dose adjustments should be made when necessary. 

The toxicities associated with interferon-a2b therapy are significant and require patient education, close patient monitoring, and appropriate dose delay and/or reduction. 

Effect on theophylline Cl may be dose-dependent and was modest at 600 mg/day monitoring of serum concentrations and appropriate dose reduction if indicated. 

Serum concentration monitoring and appropriate dose reduction should be performed. 

Serum concentration monitoring and appropriate dose reduction should be performed. The effect might not be clinically significant for the majority of patients. 

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