Levo-carnitine (L-carnitine) is a naturally occurring amino acid derivative that is essential for the transport of long-chain fatty acids into the mitochondrial matrix for beta-oxidation and energy production. The 'NA' designation typically refers to its formulation as a nutritional supplement or as a prescription drug for specific deficiencies. In the Indian market, it is used both as a prescription medicine for primary and secondary carnitine deficiencies and as a widely available over-the-counter supplement for various conditions.
Adult: Deficiency States: Oral: 990 mg to 2,970 mg per day in 2-3 divided doses. IV: 50 mg/kg as a bolus or infusion, up to a maximum of 3 g per dose. Hemodialysis: IV: 20 mg/kg post-dialysis (typically 1-3 g).
Note: Oral: Take with meals to reduce GI upset. Tablets/Capsules should be swallowed whole. Liquid formulations can be taken directly or mixed with drinks. IV: Must be diluted and administered as a slow infusion over 2-3 minutes or as a 2-3 hour infusion for larger doses. Never administer as a rapid IV bolus.
L-carnitine is a cofactor required for the transport of activated long-chain fatty acids (acyl-CoA esters) from the cytosol into the mitochondrial matrix. This transport is mediated by the carnitine palmitoyltransferase (CPT) system (CPT I and CPT II) and the carnitine-acylcarnitine translocase. Inside the mitochondria, fatty acids undergo beta-oxidation to produce acetyl-CoA, which enters the Krebs cycle for ATP generation.
Pregnancy: Category B. Endogenous substance. Use only if clearly needed. No well-controlled studies in pregnant women. Risk likely low, but benefit should outweigh risk.
Driving: Unlikely to affect ability. However, if dizziness or seizures occur, avoid driving.
| Valproic Acid / Valproate | Valproate depletes carnitine levels. Concurrent use may require higher L-carnitine doses to prevent deficiency. | Major |
| Warfarin | Theoretical interaction; L-carnitine may potentiate anticoagulant effect. Monitor INR closely. | Moderate |
| Thyroid Hormones (Levothyroxine) | L-carnitine may inhibit peripheral action of thyroid hormone. Monitor thyroid function. | Moderate |
| Acitretin, Isotretinoin | May increase risk of myalgia and elevated CPK. Monitor. | Moderate |
| Zidovudine (AZT) | L-carnitine may reduce AZT-induced myopathy. | Minor (Beneficial) |
Same composition (Levo-carnitine (NA)), different brands: