Calcium intravenous, adverse effects

Felodipine is a dihydropyridine derivative with diuretic properties (1). Its diuretic properties are not unique but are shared by other dihydropyridines. Its vasodilator-related adverse effects include flushing, headache, and tachycardia (2,3). Reduced arterial oxygen saturation has been seen in patients given intravenous felodipine for pulmonary hypertension (4,5). Along with amlodipine, but unlike other calcium channel blockers, felodipine may be safer in severe chronic heart failure accompanied by angina or hypertension. 

Mithramycin (plicamycin) is a potent cytotoxic antibiotic that inhibits osteoclast-mediated bone resorption and thereby reduces hypercalcemia. Mithramycin may be administered at a dose of 25 mcg/kg via intravenous infusion over 4 to 6 hours in saline or 5% dextrose solutions. This therapy may be repeated daily for 3 to 4 days or on alternating days for 3 to 8 doses. ° Serum calcium levels begin to fall within 12 hours of a mithramycin dose, with the peak effect generally occurring within 48 to 96 hours.Single doses are usually well tolerated. Adverse effects of mithramycin include nausea, vomiting, stomatitis, thrombocytopenia, inhibition of platelet function, and renal and hepatotoxicity. Because these adverse effects are more commonly associated with multiple doses, mithramycin is usually limited to short-term therapy in patients who have not responded to alternative therapies. Monitoring parameters include complete blood count, liver function, and renal function. Mithramycin should be avoided in patients with thrombocytopenia and liver and renal insufficiency. ... 

Besides local toxicity, discussed above, there are numerous other modes of potential adverse interactions involving excipients (19,20). Many of these pose little threat provided the amounts of excipients are constrained to certain levels. Excessive amounts, however, can cause problems, particularly for patients who are intolerant of even modest levels. Commonly used phosphate buffers may cause calcium loss with formation of insoluble calcium phosphates when such buffers are administered in over-ambitious amounts (21). Calcium phosphate precipitation has been noted particularly in nutritional parenteral admixtures for neonates because of the high nutrient requirements. Similarly, renal toxicity has been associated with depletion of zinc and other trace metals caused by large parenteral doses of ethylenediaminete-traacetic acid (EDTA) (22). Excessive absorption of glycine solutions, when used as irrigants during transurethral resections, can cause hyponatremia, hypertension, and confusion (23). The use of preservatives has been associated with cardiac effects in a few patients (24). Premature neonates were found to be at risk for receiving toxic amounts of benzoic acid or benzyl alcohol in bacteriostatic solutions used to flush intravenous catheters (25). 

Adverse respiratory effects are uncommon with calcium channel blockers. However, three cases of acute broncho-spasm accompanied by urticaria and pruritus have been reported in patients taking verapamil (51), and a patient with Duchenne-type muscular dystrophy developed respiratory failure during intravenous verapamil therapy for supraventricular tachycardia (52). Recurrent exarcer-bations of asthma occurred in a 66-year-old lady with hypertension and bronchial asthma given modified-release verapamil (53). 

An insulin infusion should be considered for severe cases of calcium channel blocker toxicity." Case reports suggest that an intravenous bolus of regular insulin (0.5-1 units/kg) with 50 mL dextrose 50% (0.25 mg/kg for children) followed with a continuous infusion of regular insulin (0.5-1 units/kg per hour) may improve myocardial contractility. The effect of insulin is presently unclear, but it may improve myocardial metabolism that is adversely affected by calcium channel blocker overdoses, such as decreased cellular uptake of glucose and free fatty acids and a shift from fatty acid oxidation to carbohydrate metabolism. This insulin regimen is titrated to improvement in systolic blood pressure over 100 mm Hg and heart rate... 

It has been noted that amitriptyline increases the effects of both disulflram and citrated calcium carbimide without any increase in adverse effeets. However, there is also some evidence that an adverse interaction can occur. A study in two men found that disulfiram 500 mg daily increased the AUC of imipramine (12.5 mg given intravenously after an overnight fast) by about 30%, and of desipramine 12.5 mg given intravenously in one subject by a similar amount. Peak plasma levels were also increased. The suggest reason is that the disulfiram inhibits the metabolism of the antidepressants by the liver. There is also a report of a man taking disulfiram who, when given amitriptyline, complained of dizziness, visual and auditory hallucinations, and who became disorientated to person, plaee and time. A similar reaction was seen in another patient. Concurrent use should therefore be well monitored for any evidence of toxicity. 

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