What is Tham (Tromethamine)?
Tham is a brand name for tromethamine, a sterile, injectable solution used as a systemic alkalizing agent. It is administered intravenously to prevent and correct severe metabolic acidosis, a condition where excessive acid builds up in the body. Tromethamine buffers hydrogen ions without generating carbon dioxide, setting it apart from other alkalizers like sodium bicarbonate.
History and Current Availability
Production of the brand-name Tham was discontinued in the United States in 2016 due to manufacturing decisions. This made sodium bicarbonate the primary alkali therapy. However, it was later determined the withdrawal was not for safety or effectiveness reasons, allowing for the reintroduction of generic tromethamine injections by other manufacturers.
Mechanism of Action and Clinical Applications
Tromethamine works by accepting protons ($H^+$), helping to correct the low blood pH in acidosis. It buffers acid in both extracellular and intracellular fluid. Key clinical uses include:
- Cardiac Bypass Surgery: Corrects metabolic acidosis during or after the procedure and can be added to blood used in pump-oxygenators.
- Metabolic Acidosis in Cardiac Arrest: Used with resuscitation efforts to correct acidosis and potentially improve heart function.
- Neonates and Infants: Treats severe metabolic and respiratory acidosis, avoiding the problematic CO2 increase associated with bicarbonate in infants with breathing difficulties. Close monitoring is needed due to risks like hypoglycemia.
Tham vs. Sodium Bicarbonate: A Comparison
While sodium bicarbonate has been a standard alkali therapy, tromethamine offers advantages in certain situations. The table below highlights key differences:
| Feature | Tromethamine (THAM) | Sodium Bicarbonate (NaHCO3) |
|---|---|---|
| Mechanism | Buffers hydrogen ions directly. | Introduces bicarbonate, which creates carbonic acid and then CO2. |
| CO2 Production | Does not generate CO2; may lower arterial CO2. | Increases CO2 levels. |
| Sodium Load | Sodium-free. | Significant sodium load. |
| Intracellular Buffering | Buffers both extracellular and intracellular fluid. | Primarily buffers extracellular fluid. |
| Effect on Potassium | May cause hyperkalemia. | Can decrease serum potassium. |
Important Considerations, Side Effects, and Precautions
Tromethamine requires careful medical supervision and monitoring of blood gases, glucose, and electrolytes.
Potential side effects include hypoglycemia, respiratory depression, hyperkalemia, and tissue necrosis if it leaks into surrounding tissue. It is contraindicated in patients with anuria or uremia and should not be used in neonates with chronic respiratory acidosis or salicylate intoxication. It is also important not to confuse tromethamine with ketorolac tromethamine.
Conclusion
Tham (tromethamine) is a potent systemic alkalizer used in critical care for severe metabolic acidosis in conditions like cardiac arrest and cardiac bypass surgery. Its advantages, such as not producing carbon dioxide and being sodium-free, make it preferable to sodium bicarbonate in certain clinical contexts. Although previously unavailable, generic versions have restored its use for managing life-threatening acid-base imbalances. Healthcare providers must carefully monitor patients for potential side effects, including hypoglycemia and hyperkalemia. Further information on its use can be found through resources like {Link: PubMed https://pubmed.ncbi.nlm.nih.gov/9506241/} and {Link: National Institutes of Health https://www.ncbi.nlm.nih.gov/books/NBK482352/}.
