A combination of heparin and alkalinized lidocaine provides significantly better relief of interstitial cystitis (IC) symptoms compared with alkalinized lidocaine alone, according to a new study.
For the crossover study, investigators led by C. Lowell Parsons, MD, of the University of California San Diego Health System, treated 14 IC patients with a heparin-alkalinized lidocaine combination or alkalinized lidocaine alone on different days, when they had pain. The patients were blinded to the solutions they received, which were administered via catheter into the empty bladder. Before and after each treatment, the patients assessed their symptoms via questionnaires.
Compared with lidocaine alone, the heparin-lidocaine combo provided better reduction of bladder pain (38% vs. 13%) and urgency (42% vs. 8%), according to study results published in the Canadian Journal of Urology. The patients likewise reported better immediate and long-term improvement at 1 hour (77% vs. 50%) and 24 hours (57% vs. 23%) after the combination treatment.
“These data support the rationale for combining the drugs, lidocaine to anesthetize the nerves and heparin to augment the bladder’s defective permeability barrier seen in patients with IC,” the researchers stated. “It also appears that the presence of the heparin is important to stabilize lidocaine solubility when it is alkalinized.” The heparin-lidocaine combination was a 15 ml solution of 50,000 units of heparin and 200 mg of USP lidocaine hydrochloride buffered to pH 7.2.
The researchers separately conducted a second study with a different set of patients to further assess the efficacy of the drug combination. They determined (via chromatography) that serum lidocaine levels were more than twice as high with the heparin-lidocaine combination compared with unalkalinized USP lidocaine, supporting the clinical activity seen in the original study. They now suggest a 4-arm study to further test the heparin-lidocaine combination.