The route originally used by Dr Costantini to administer thiamine (B1) was the intramuscular route (Costantini, 2013) (The Scientific Evidence). That route has the advantage of thiamine’s bypassing intestinal absorption and being absorbed quickly and fully. On the other hand, it has the disadvantage of requiring some assistance for the injections; it needs a prescription from a physician. There is a small risk of anaphylaxis with parenteral thiamine, with repeated injections (Wrenn, 1989; Morinville, 1998; Costantini, HDT website). This risk has been found to be mostly associated with intravenous administration (EFSA, 2006). To be safe, parenteral administration should be performed in facilities equipped to treat anaphylaxis promptly. Thiamine by i.m. was the only formulation available in Italy when Dr Costantini started using thiamine in PwP and was the route used in previous PD case reports (Luong, 2012).

Selected references

Costantini, MI Pala, L. Compagnoni, M. Colangeli, High-dose thiamine as initial treatment for Parkinson's disease, BMJ Case Rep 2013 Aug 28, ii: bcr2013009289.

Wrenn KD, Murphy F, Slovis CM. A toxicity study of parenteral thiamine hydrochloride. Ann Emerg Med. 1989 Aug;18(8):867-70.

V Morinville, N. Jeannet-Peter, C. Hauser “Anaphylaxis to parenteral thiamine (vitamin B1)” Case Reports, Schweiz Med Wochenschr. 1998 Oct 31;128(44):1743-4.

Dr Costantini’s website on High-dose Thiamine (HDT) Therapy for Parkinson’s Disease, Accessed 28.02.2023

The Scientific Committee on Food and Scientific Panel on Dietetic Products, Nutrition and Allergies of the European Food Safety Authority, Tolerable Upper Intake Levels for Vitamins and minerals, February 2006, European Food Safety Authority

Khanh vinh quoc Luong, Lan Thi Hoang Nguyen, The Beneficial Role of Thiamine in Parkinson’s Disease: Preliminary Report, J Neurol Res. 2012, 2 (5):211-214

Text author: Sergio Pièche
Page updated - 24/04/23