Parenterals

Parenterals are formulations intended for administration by routes other than the gastrointestinal tract. This includes injections and infusions given intravenously, intramuscularly, subcutaneously, or via other routes such as intrathecal or epidural. The term also covers parenteral nutrition delivered completely by intravenous infusion.

Parenteral administration is used when oral or enteral routes are not feasible, such as in comatose patients, severe nausea or vomiting, gastrointestinal malabsorption, or when rapid systemic effect is required. Parenterals include a wide range of products: sterile drug solutions, emulsions, suspensions, and complex admixtures; vaccines and biologics administered by injection are also parenteral products.

Parenteral products must be sterile, free of pyrogens, and prepared under aseptic conditions. They are packaged in vials, ampoules, or bags and are intended for administration via needles or catheters connected to an infusion device. IV infusions may be continuous or intermittent; central venous access is common for long-term therapy or nutrition.

Total parenteral nutrition (TPN) provides all daily nutrients through a central venous line, combining glucose, amino acids, lipids, electrolytes, vitamins, and trace elements. Peripheral parenteral nutrition (PPN) uses smaller volumes via peripheral veins. Lipid emulsions are often administered separately or with amino acids and dextrose. Monitoring includes blood glucose, electrolyte balance, liver function, and catheter care.

Risks include infection, catheter-related complications, phlebitis, air embolism, metabolic imbalances, and compatibility issues among components. Standards for aseptic technique, product validation, and labeling apply, along with regulatory guidelines and pharmacopoeial specifications for excipients, stability, and storage.