Levocarnitine propionate or Propionyl L-carnitine (PLC) is the propionyl ester of L-carnitine. Propionyl-L-carnitine stimulates energy production in ischaemic muscles by increasing citric acid cycle flux and stimulating pyruvate dehydrogenase activity. The free radical scavenging activity of the drug may also be beneficial. Propionyl-L-carnitine improves coagulative fibrinolytic homeostasis in vasal endothelium and positively affects blood viscosity. It exhibits a high affinity for the muscle enzyme, carnitine acyl transferase, and as such readily converts into propionyl-CoA and free carnitine. Most studies of the therapeutic use of PLC are focused on the prevention and treatment of ischemic heart disease, congestive heart failure, hypertrophic heart disease, and peripheral arterial disease. PLC is marketed under the trade name Dromos®. It is indicated for patients with peripheral arterial occlusive disorders and for exercise intolerance enhancement in patients with chronic congestive heart failure. Dromos is marketed in Italy.

Valproic acid (VPA; valproate; di-n-propylacetic acid, DPA; 2-propylpentanoic acid, or 2-propylvaleric acid) was first synthesized in 1882, by Burton. FDA approved valproic acid for the treatment of manic episodes associated with bipolar disorder, for the monotherapy and adjunctive therapy of complex partial seizures and simple and complex absence seizures and adjunctive therapy in patients with multiple seizure types that include absence seizures and for the prophylaxis of migraine headaches. The mechanisms of VPA which seem to be of clinical importance in the treatment of epilepsy include increased gamma-aminobutyric acid (GABA)-ergic activity, reduction in excitatory neurotransmission, and modification of monoamines. Recently, it was discovered that the VPA is a class I selective histone deacetylase inhibitor. This activity can be distinguished from its therapeutically exploited antiepileptic activity.