Levocarnitine

Overview

Levocarnitine is the biologically active L-isomer of carnitine and a normal component of human metabolism. The US CARNITOR injection label approves it for acute and chronic treatment of secondary carnitine deficiency caused by inborn errors of metabolism, and for prevention and treatment of carnitine deficiency in patients with end-stage renal disease undergoing dialysis.

Identity and chemistry

The label describes a zwitterionic inner salt and a sterile injection containing 1 g levocarnitine per 5 mL. This identity must not be mixed with L-carnitine L-tartrate.

Physiological role

Levocarnitine transports long-chain fatty acids across the inner mitochondrial membrane, making them available for oxidation and energy production. In several inherited metabolic disorders it also helps form acylcarnitines that can be excreted. These functions explain the deficiency indications; they do not by themselves prove benefit for fat loss, athletic performance or general wellness.

Approved clinical context

The official label names two contexts: secondary deficiency from inborn metabolic errors, and deficiency in end-stage renal disease during maintenance hemodialysis. For dialysis patients, the label states that plasma concentrations increase with treatment but that effects on symptoms and clinical outcomes were not determined. Approval therefore should not be broadened beyond the labeled population.

Pharmacokinetics

After a 20 mg/kg intravenous dose, the label reports a mean distribution half-life of 0.585 hours and an apparent terminal elimination half-life of 17.4 hours; about 76% of the dose was recovered in urine within 24 hours. These values come from a defined intravenous study and should not be generalized to every route or clinical state.

Safety

The label reports transient nausea and vomiting, less frequent body odor and gastritis, postmarketing seizures or increased seizure activity, and serious hypersensitivity reactions including anaphylaxis, laryngeal edema and bronchospasm. Warfarin users have had reported INR increases. Renal impairment also changes the relevance of metabolites after chronic high oral exposure.

Label dosing — not general advice

For metabolic disorders, the label recommends 50 mg/kg intravenously, administered and repeated according to the detailed crisis and maintenance instructions with plasma-carnitine and clinical monitoring. For hemodialysis, it gives a starting dose of 10–20 mg/kg dry body weight intravenously after each dialysis session, adjusted using trough concentrations.

Evidence conclusion

Levocarnitine has a clear chemical identity, physiological role and US prescription status for narrow deficiency indications. The key editorial boundary is equally clear: approval of CARNITOR does not validate PeptideGuide’s injectable tartrate identity or non-label metabolic claims.