Infusion rates renal impairment

A loading dose of 0.2 mg/kg (repeated up to a maximum of 2 mg/kg) followed by a continuous infusion of 0.05 to 2 mg/kg per hour is recommended in RSE.29-31 The dose must be adjusted during prolonged infusions, especially in patients with renal impairment, as the active metabolite can accumulate.32 Breakthrough seizures are common with midazolam infusions and usually respond to a bolus and a 20% increase in the rate. Despite this, tachyphylaxis can occur and the patient should be switched to another agent if seizure activity continues. 

Reduction of Lepirudin infusion Rate in Patients with Renal Impairment ... 

Renal function impairment W th renal impairment, relative overdose might occur even with a standard dosage regimen. In patients with marked renal insufficiency (creatinine clearance less than 15 mL/min) and on hemodialysis, elimination half-lives are prolonged 2 days or less. Reduce the bolus dose and rate of infusion in patients with known or suspected renal insufficiency (see Administration and Dosage). 

Patients who present with heat exhaustion require fluid resuscitation. An attempt should be made to assess the amount of salt depletion and dehydration. This may be difficult clinically although the presence of symptoms such as muscle cramps in sodium depletion, and signs such as loss of tissue turgor may help. Laboratory measurement of sodium, urea, creatinine and haematocrit are the best guide. Pre-renal renal impairment is common. Treatment usually requires 5-10 1 of oral or intravenous isotonic fluids in the first 24 hours. In severe hyponatraemia the rapid correction of sodium should be carefully monitored with frequent sodium measurements and a reduction in fluid infusion rate if necessary to reduce the risk of osmotic demyelination (central pontine myelinol-ysis). 

Heparin-induced thrombocytopenia and associated thromboembolic disease to prevent further thromboembolic complications IV, IV Infusion 0.2-0.4 mg/kg, IV slowly over 15-20 sec, followed by IV infusion of 0.1-0.15 mg/kg/hr for 2-10 days or longer. Dosaye in renal impairment Initial dose is decreased to 0.2 mg/kg, with infusion rate adjusted based on creatinine clearance. 

Special Precautions Exceeding recommended dosage and infusion rate could result in increased toxicity Dosage adjustment is required in presence of renal impairment Phlebitis and pain may occur at injection site... 

Radiopharmaceutical, to be prepared and administered only by personnel trained in radiopharmaceuticals premedicate with acetaminophen and antihistamines slow infusion rate or interrupt infusion for infusion reactions medications for treatment of hypersensitivity reactions should be available for immediate use avoid in pregnant females may cause hypothyroidism in fetus two-step administration MoAB and low radioisotope dose is followed after 1-2 weeks by MoAB and therapeutic radioisotope dose renally excreted impaired renal function may increase exposure to radioactive components patients must be trained in precautions to decrease radiation exposure to family, friends, and general public... 

Equation 10.10 is important since it allows us to determine the number of elimination half lives of a drug required to attain a given fraction of the tme steady state. It should he clear from Eq. 10.10 that the number of elimination half lives required to attain a given fraction of steady state will always be the same, regardless of the value of the elimination half life of the drug, the infusion rate chosen and whether the drug was administered to normal or renally impaired subjects. 

Should the patient manifest renal impairment for a drug eliminated by the kidneys, the infusion rate required to maintain the desired steady-state plasma concentration will be smaller and, please note, the elimination rate constant will also be smaller by an identical amount therefore, the ratio of infusion rate over elimination rate constant remains unaffected. This simply suggests, therefore, that it is vitally important to adjust (lower) the infusion rate of drug in a renally impaired subject. However, adjustment in the loading dose is neither necessary nor required. This statement can further be supported upon careful examination of Eq. 10.15, which clearly suggests that the... 

The ratio of first infusion rate over second infusion rate (i.e. Q1/Q2) will always be equal to 2 if the time at which the first infusion rate is changed to second infusion rate is equal to the elimination half life of the drug. The elimination half life for each drug may be different and, therefore, the time at which the first infusion rate is changed to the second infusion rate will differ for each drug or, for that matter, in the same subject if there is evidence of renal or hepatic impairment (which can decrease the value of fQ. 

Show the profile (rectilinear paper) of infusion rate necessary to attain a true steady-state plasma concentration against the systemic clearance or against the degree of renal impairment. 

Please note that (Cp)ss is influenced by the chosen infusion rate as well as the systemic clearance of a drug (renally impaired patients). 

This is provided by 0.682 mgkg h of procainamide HCl. If this infusion rate in a renally impaired subject (0.682 mgkg h ) is compared with that in a normal subject (3.186mgkg h given in question 1 above) to attain the identical procainamide plasma concentration(6 mg L ), it can be seen that the infusion rate is reduced in the renally impaired subject. 

Infusion rates of 0.1-0.15 pg/kg per min are effective for establishing and maintaining analgesia and sedation in a wide range of ICU patients, including those with severe renal or hepatic impairment. 

For those patients with normal to moderately impaired renal function, the cornerstone of initial treatment of hypercalcemia is volume expansion to increase urinary calcium excretion (see Table 49-6). Patients with severe renal insufficiency usually do not tolerate volume expansion they may be initiated on therapy with calcitonin. Patients with symptomatic hypercalcemia are often dehydrated secondary to vomiting and polyuria thus rehydration with saline-containing fluids is necessary to interrupt the stimulus for sodium and calcium reabsorption in the renal mbule. ° Rehydration can be accomplished by the infusion of normal saline at rates of 200 to 300 mL/h, depending on concomitant conditions (primarily cardiovascular and renal) and extent of hypercalcemia. Adequacy of hydration is assessed by measuring fluid intake and output or by central venous pressure monitoring. Loop diuretics such as furosemide (40 to 80 mg IV every 1 to 4 hours) or ethacrynic acid (for patients with sulfa allergies) may also be instiffited to increase urinary calcium excretion and to minimize the development of volume overload from the administration of saline (see Table 49-6). Loop diuretics such as furosemide... 

The dose of ammonium chloride can be calculated on the basis of the chloride deficit using the same method as for HCl, using the conversion of 20 g ammonium chloride providing 374 mEq of H . However, only half of the calculated dose of ammonium chloride should be administered so as to avoid ammonia toxicity. Ammonium chloride is available as a 26.75% solution containing 100 mEq in 20 mL, which should be further diluted prior to administration. A dilute solution may be prepared by adding 100 mEq of ammonium chloride to 500 mL of normal saline and infusing the solution at a rate of no more than 1 mEq/min. Improvement in metabolic stams is usually seen within 24 hours. CNS toxicity, marked by confusion, irritability, seizures, and coma, has been associated with more rapid rates of administration. Ammonium chloride must be administered cautiously to patients with renal or hepatic impairment. In patients with hepatic dysfunction, impaired conversion of ammonia to urea may result in increased ammonia levels and worsened encephalopathy. In patients with renal failure, the increased urea synthesis may exacerbate uremic symptoms. ... 

Hyperkalemia may be caused by increased supply (infusion, blood transfusion, medicaments), shift of potassium from the intra- to the extracellular space (in postoperative or posttraumatic states or following bums), or impaired elimination in severe renal insufficiency accompanied by an extremely reduced glomemlar filtration rate as well as in deficiency of aldosterone (Addison s disease) or other mineral corticoids. 

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