Optimal symptoms control in advanced
cancer disease, with refractory to conventional
pain treatment, needs an interventional procedure. This paper presents coadministration of
local anesthetic (LA) via paravertebral blockade (PVB) as the alternative to an unsuccessful subcutaneous
fentanyl pain control in a 71-year old
cancer patient with
pathological fracture of femoral neck, bone
metastases, and
contraindications to
morphine.
Bupivacaine in continuous infusion (0.25%, 5 mL · hour(-1)) or in boluses (10 mL of 0.125%-0.5%
solution), used for lumbar PVB, resulted in
pain relief, decreased demand for
opioids, and led to better social interactions. The factors contributing to an increased risk of systemic toxicity from LA in the patient were: renal impairment;
heart failure;
hypoalbuminemia;
hypocalcemia; and a complex
therapy with possible
drug-drug interactions. These factors were taken into consideration during treatment.
Bupivacaine's side effects were absent. Coadministered drugs could mask LA's toxicity. Elevated plasma α1-acid
glycoprotein levels were a protective factor. To evaluate the benefit-risk ratio of the PVB treatment in boluses and in constant infusion,
bupivacaine serum levels were determined and the
drug plasma half-lives were calculated.
Bupivacaine's elimination was slower when administered in constant infusion than in boluses (t½ = 7.80 hours versus 2.64 hours). Total
drug serum concentrations remained within the safe ranges during the whole treatment course (22.9-927.4 ng mL(-1)). In the case presented, lumbar PVB with
bupivacaine in boluses (≤ 137.5 mg · 24 hours(-1)) was an easy to perform, safe, effective method for
pain control.
Bupivacaine in continuous infusion (≤150 mg · 12 hours(-1)) had an acceptable risk-benefits ratio, but was ineffective.