Alkaline diuresis, forced

The method does not distinguish between the common 5,5-substituted barbiturates. If the physician proposes to institute a forced alkaline diuresis or haemodialysis, it is essential to confirm the presence of a long-acting barbiturate (e.g, barbitone, phenobarbitone) by thin-layer chromatog-raphy or gas chromatography. 

The effect of varying urinary pH has been used in the treatment of drug overdose by applying forced alkaline diuresis as an adjunct to the treatment of salicylate or phenobarbitone poisoning. The success of the treatment is limited by the extent to which these drugs are distributed, and by the presence of... 

The principal site of excretion that is liable to drag interactions is in the kidney. The classic example is forced alkaline diuresis using intravenous sodium... 

Hefi ier and Sahn, 1981). In the case of salicylate-induced edema, drug levels can be lowered with forced alkaline diuresis and then pulmonary edema clears quickly. 

Aspirin is encountered frequently in the laboratory in overdose cases. It directly stimulates the respiratory centre in the brain causing hyperventilation and a resultant respiratory alkalosis. Later, a metabolic acidosis is superimposed on this and the acid-base picture becomes more complex. Potassium levels should therefore be monitored closely. Removal ofthedrugfrom the circulation is encouraged by forced alkaline diuresis. 

Push fluids. Severe toxicity needs IV hydration + forced pressure alkaline diuresis or... 

A 21-month-old girl was prescribed erythromycin for an upper respiratory tract infection. At the same time, her parents had been giving her approximately 300 mg of aspirin every 4 hours. The child s condition deteriorated and 2 days later she was admitted to hospital with a temperature of 105°F. She was then prescribed more aspirin, and shortly thereafter had a convulsion for which she was given phenobarbitonc, dexamethasone and tetracycline. Fluid therapy was started, but there was no urine output, and she became progressively obtunded and hyperpnoeic. The patient was transferred to another hospital where the diagnosis to salicylate poisoning was made. She appeared well hydrated, the arterial blood pH was 7.26 and the serum salicylate concentration was 470 Mg/ml. Forced alkaline diuresis was started but had to be restricted because of poor urine output, periorbital oedema and hyponatraemia. The plasma osmolality fell to 264 mOsm/1. Diuresis with recovery eventually followed fluid restriction and administration of mannitol (20 -). 

Tetany is a rare complication of salicylate poisoning, and is probably due to the combination of hypocalcaemia and alkalosis caused by hyperventilation and forced alkaline diuresis. In one recently reported case prolonged tetany was followed by a bilateral... 

The basic treatment of moderate to severe salicylate poisoning is gastric aspiration and lavage followed by forced alkaline diuresis. If there is doubt concerning fluid balance, therapy may be monitored by a central venous catheter (33 -). Acetazol-amide is very effective in raising urine pH but it aggravates acidosis and increases the toxicity and lethality of salicylate in mice (34). It should be avoided. 

Consider forced diuresis, urine acidification, or alkalinization if specific antidotes are not available Hemodialysis or charcoal hemoperfusion may be appropriate for rapid elimination if antidotes are not available... 

Previously popular but of unproved value, forced diuresis may cause volume overload and electrolyte abnormalities and is not recommended. Renal elimination of a few toxins can be enhanced by alteration of urinary pH. For example, urinary alkalinization is useful in cases of salicylate overdose. Acidification may increase the urine concentration of drugs such as phencyclidine and amphetamines but is not advised because it may worsen renal complications from rhabdomyolysis, which often accompanies the intoxication. 

When a dmg is in its unionised form it will more readily diffuse from the urine to the blood. In an acidic urine, acidic drugs will diffuse back into the blood from the urine. Acidic compounds such as nitrofurantoin are excreted faster when the urinary pH is alkaline. Amfetamine, imipramine and amitriptyline are excreted more rapidly in acidic urine. The control of urinary pH in studies of pharmacokinetics is thus vital. It is difficult, however, to find compounds to use by the oral route for deliberate adjustment of urinary pH. Sodium bicarbonate and ammonium chloride may be used but are unpalatable. Intravenous administration of acidifying salt solutions presents one approach, especially for the forced diuresis of basic dmgs in cases of poisoning. 

---