Tromethamine

Tham Solution (tromethamine injection) is indicated for the prevention and correction of metabolic acidosis. In the following conditions it may help to sustain vital functions and thus provide time for treatment of the primary disease: Metabolic Acidosis Associated with Cardiac Bypass Surgery. Tham Solution has been found to be primarily beneficial in correcting metabolic acidosis which may occur during or immediately following cardiac bypass surgical procedures. Correction of Acidity of ACD Blood in Cardiac Bypass Surgery. It is well known that ACD blood is acidic and becomes more acidic on storage. Tromethamine effectively corrects this acidity. Tham Solution may be added directly to the blood used to prime the pump-oxygenator. When ACD blood is brought to a normal pH range the patient is spared an initial acid load. Additional tromethamine may be indicated during cardiac bypass surgery should metabolic acidosis appear. Metabolic Acidosis Associated with Cardiac Arrest. Acidosis is nearly always one of the consequences of cardiac arrest and, in some instances, may even be a causative factor in arrest. It is important therefore, that the correction of acidosis should be started promptly with other resuscitative efforts. By correcting acidosis, Tham Solution (tromethamine injection) has caused the arrested heart to respond to resuscitative efforts after standard methods alone had failed. In these cases, tromethamine was given intraventricularly. It is to be noted, however, that such precariously ill patients often have died subsequently of causes unrelated to the administration of tromethamine. With administration by the peripheral venous route, metabolic acidosis has been corrected in a majority of patients. The success in reinstitution of cardiac rhythm by this means probably has not been of the same order of magnitude as with the intraventricular route.

Tham Solution (tromethamine injection) is contraindicated in uremia and anuria. In neonates it is also contraindicated in chronic respiratory acidosis and salicylate intoxication.

Large doses of Tham Solution may depress ventilation, as a result of increased blood pH and reduced CO 2 concentration. Thus, dosage should be adjusted so that blood pH is not allowed to increase above normal. In situations in which respiratory acidosis may be present concomitantly with metabolic acidosis, the drug may be used with mechanical assistance to ventilation. Care must be exercised to prevent perivascular infiltration since this can cause inflammation, necrosis and sloughing of tissue. Venospasm and intravenous thrombosis, which may occur during infusion, can be minimized by insuring that the injection needle is well within the largest available vein and that solutions are slowly infused. Intravenous catheters are recommended. If perivascular infiltration occurs, institute appropriate countermeasures (see ADVERSE REACTIONS ). Tham Solution (tromethamine injection) should be administered slowly and in amounts sufficient only to correct the existing acidosis, and to avoid overdosage and alkalosis. Overdosage in terms of total drug and/or too rapid administration, may cause hypoglycemia of a prolonged duration (several hours). Therefore, frequent blood glucose determinations should be made during and after therapy. Extreme care should be exercised in patients with renal disease or reduced urinary output because of potential hyperkalemia and the possibility of a decreased excretion of tromethamine. In such patients, the drug should be used cautiously with electrocardiographic monitoring and frequent serum potassium determinations. Because clinical experience has been limited generally to short-term use, the drug should not be administered for more than a period of one day except in a life-threatening situation. The intravenous administration of Tham Solution can cause fluid and/or solute overloading resulting in dilution of serum electrolyte concentrations, overhydration, congested states or pulmonary edema. Additives may be incompatible. Consult with pharmacist, if available. When introducing additives, use aseptic technique, mix thoroughly and do not store.

Blood pH, PCO 2 bicarbonate, glucose and electrolyte determinations should be performed before, during and after administration of Tham Solution. While it has not been shown that the drug increases coagulation time in humans, this possibility should be kept in mind since this has been noted experimentally in dogs. Do not administer unless solution is clear and seal is intact. Discard unused portion. Pregnancy: Animal reproduction studies have not been conducted with tromethamine. It is also not known whether tromethamine can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Tromethamine should be given to a pregnant woman only if clearly needed. Nursing Mothers: It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when THAM Solution is administered to a nursing mother. Carcinogenesis, Mutagenesis, Impairment of Fertility: Studies with THAM Solution have not been performed to evaluate carcinogenic potential, mutagenic potential or effects on fertility. Pediatric Use: The safety and effectiveness of THAM Solution in pediatric patients is based on over 30 years’ clinical experience documented in the literature and on safety surveillance. THAM Solution has been used to treat severe cases of metabolic acidosis with concurrent respiratory acidosis because it does not raise PCO 2 as bicarbonate does in neonates and infants with respiratory failure. It has also been used in neonates and infants with hypernatremia and metabolic acidosis to avoid the additional sodium given with the bicarbonate. However, because the osmotic effects of THAM Solution are greater and large continuous doses are required, bicarbonate is preferred to THAM Solution in the treatment of acidotic neonates and infants with RDS. Hypoglycemia may occur when this product is used in premature and even full-term neonates (see WARNINGS and ADVERSE REACTIONS ). Geriatric Use: Clinical studies of Tham solution did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in response between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

Generally, side effects have been infrequent. Respiratory: Although the incidence of ventilatory depression is low, it is important to keep in mind that such depression may occur. Respiratory depression may be more likely to occur in patients who have chronic hypoventilation or those who have been treated with drugs which depress respiration. In patients with associated respiratory acidosis, tromethamine should be administered with mechanical assistance to ventilation. Vascular: Extreme care should be taken to avoid perivascular infiltration. Local tissue damage and subsequent sloughing may occur if extravasation occurs. Chemical phlebitis and venospasm also have been reported. Hematologic: Transient depression of blood glucose may occur. Hepatic: Infusion via low-lying umbilical venous catheters has been associated with hepatocellular necrosis. Reactions which may occur because of the solution or the technique of administration include febrile response, infection at the site of injection, venous thrombosis or phlebitis extending from the site of injection extravasation and hypervolemia. If an adverse reaction does occur, discontinue the infusion, evaluate the patient, institute appropriate therapeutic countermeasures and save the remainder of the fluid for examination if deemed necessary.

Animal reproduction studies have not been conducted with tromethamine. It is also not known whether tromethamine can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Tromethamine should be given to a pregnant woman only if clearly needed.

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when THAM Solution is administered to a nursing mother.

The safety and effectiveness of THAM Solution in pediatric patients is based on over 30 years’ clinical experience documented in the literature and on safety surveillance. THAM Solution has been used to treat severe cases of metabolic acidosis with concurrent respiratory acidosis because it does not raise PCO 2 as bicarbonate does in neonates and infants with respiratory failure. It has also been used in neonates and infants with hypernatremia and metabolic acidosis to avoid the additional sodium given with the bicarbonate. However, because the osmotic effects of THAM Solution are greater and large continuous doses are required, bicarbonate is preferred to THAM Solution in the treatment of acidotic neonates and infants with RDS. Hypoglycemia may occur when this product is used in premature and even full-term neonates (see WARNINGS and ADVERSE REACTIONS ).

Clinical studies of Tham solution did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in response between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.