Doses therapy

Prolonged high-dose therapy of the adrenergic drugs can produce cyanosis and tissue necrossof distal extremities It is important to remember to use the lowest posable dose that producesan adequate response for the shortest period of time. The nurse monitors the patient s extremitiescloseiy for any signs of cyanosis... 

The patient demonstrates an understanding of die importance of not suddenly discontinuing therapy (long-term or high-dose therapy). 

Methotrexate -antifolate antimetabolite cell cycle dependent -bone marrow suppression -nausea and vomiting—mild to moderate -mucocutaneous effects (mucositis, stomatitis, diarrhea) -hepatotoxicity—more common in high-dose therapy -CNS toxicity—dizziness, malaise, blurred vision, encephalopathy -nephrotoxicity—including acute renal failure, particularly at high doses... 

Anaemia often becomes a characteristic feature of several chronic diseases, such as rheumatoid arthritis. In most instances this can be linked to lower than normal endogenous serum EPO levels (although in some cases a deficiency of iron or folic acid can also represent a contributory factor). Several small clinical trials have confirmed that administration of EPO increases haematocrit and serum haemoglobin levels in patients suffering from rheumatoid arthritis. A satisfactory response in some patients, however, required a high-dose therapy that could render this therapeutic approach unattractive from a cost benefit perspective. 

Hypokalemia and hypomagnesemia may cause muscle fatigue or cramps. Serious cardiac arrhythmias may occur, especially in patients receiving digitalis therapy, patients with LV hypertrophy, and those with ischemic heart disease. Low-dose therapy (e.g., 25 mg hydrochlorothiazide or 12.5 mg chlorthalidone daily) rarely causes significant electrolyte disturbances. 

Treatment recommendations from the CDC for syphilis are presented in Table 46-6. Parenteral penicillin G is the treatment of choice for all stages of syphilis. Benzathine penicillin G is the only penicillin effective for single-dose therapy. 

Single-dose therapy with cefotetan is adequate. Intraoperative dosing of cefoxitin may be required if the procedure extends beyond 3 hours. 

While typical doses of cefazolin are ineffective for anaerobic infections, the recommended 2-g dose produces concentrations high enough to be inhibitory to these organisms. A 24-hour duration has been used in most studies, but single-dose therapy may also be effective. 

Short-course therapy (3-day therapy) with trimethoprim-sulfamethoxazole or a fluoroquinolone (e.g., ciprofloxacin, levofloxacin, or norfloxacin) is superior to single-dose therapy for uncomplicated infection and... 

Moderate to severe vasomotor symptoms and/or moderate to severe symptoms of vulvar and vaginal atrophy associated with menopause - Start at the lowest dose. Therapy may be given continuously with no interruption, or in cyclical regimens (eg, 25 days on followed by 5 days off) as is medically appropriate on an individualized basis. 

For high-dose therapy, give 30 mg/kg IV, infused over 10 to 20 minutes. May repeat every 4 to 6 hours, not beyond 48 to 72 hours. 

Stress In patients receiving or recently withdrawn from corticosteroid therapy subjected to unusual stress, increased dosage of rapidly acting corticosteroids is indicated before, during, and after stressful situations, except in patients on high-dose therapy. 

Prolonged, high-dose therapy Prolonged, high-dose therapy can produce cyanosis and tissue necrosis of distal extremities. The principle of using the lowest dose that produces an adequate response for the shortest period of time is very important when using these agents. 

LVD after Ml - 50 mg 3 times daily is the target maintenance dose. Therapy may be initiated as early as 3 days following an Ml. After a single 6.25 mg dose, initiate at 12.5 mg 3 times daily, then increase to 25 mg 3 times daily during the next several days and to a target of 50 mg 3 times daily over the next several weeks as tolerated. 

Continue treatment of all infections for a minimum of 48 to 72 hours beyond the time that the patient becomes asymptomatic or evidence of bacterial eradication has been obtained, unless single-dose therapy is employed. 

Unlabeled uses The CDC has recommended the use of oral metronidazole for bacterial vaginosis (500 mg twice daily for 7 days). Single-dose therapy for bacterial vaginosis (2 g) also appears to be as effective as multiple-dose therapy. 

Renal function impairment There is no need to adjust single dose therapy for vaginal candidiasis in patients with impaired renal function. In patients with impaired renal function who will receive multiple doses, give an initial loading dose of 50 to 400 mg. After the loading dose, base the daily dose on the following table ... 

For lower UTI in women under 50 years of age, three days of therapy is superior than single dose therapy. In all other lower UTI 7-10 days of therapy is advised. In upper UTI 14 days is recommended. For prostatitis cotrimoxazole and fluoroquinolones reach high concentrations in the prostate but prolonged therapy (1-3 months) is necessary esp. in case of chronic prostatitis (less inflamed prostate, less penetration of the antibiotic). 

Methotrexate is approved for use in severe disabling psoriasis recalcitrant to other less toxic treatments. The standard regimen is similar to low-dose therapy used for the treatment of rheumatoid arthritis (see Chapter 36). Although toxicities are similar to those described in the treatment of other diseases, hepatic cirrhosis and unexpected pancytopenia are of special concern given the chronicity of treatment. 

---