Pharmacological Treatment of Cancer Pain: Alternative Routes of Opioid Administration

Cancer-related pain is present in 51% of patients at various stages of the disease, and the incidence increases up to 74% in advanced and terminal stages. The World Health Organization proposed and issued very simple guidelines for the pharmacologic treatment of cancer-related pain. According to the guidelines, opioid analgesics are the mainstay of analgesic therapy, and the first choice for drug administration is considered to be the oral route. However, in some clinical situations, the oral route is not feasible, and analgesic drugs consequently have to be administered via an alternative route. For example, this is the case when the patient presents vomiting, bowel obstruction, severe dysphagia, mental confusion and when the opioid dose has to be increased drastically in order to achieve adequate pain control. This review of the literature is aimed at describing the indications, the limits and the main aspects of the pharmacokinetics and pharmacodynamics relative to the alternative routes of administration of opioids most commonly used in clinical practice. Sublingual, rectal, subcutaneous, intravenous, transdermal and spinal administration routes are examined.

Long-term intrathecal opioid therapy with a patient-activated, implanted delivery system for the treatment of refractory cancer pain

The present study evaluated the safety and efficacy of patient-activated delivery of intrathecal morphine sulfate boluses delivered by way of a novel internalized intrathecal delivery system. Patients with refractory cancer pain or uncontrollable side effects were enrolled at 17 US and international sites in this prospective, open-label study. Pain relief, reduction in systemic opioid use, and reduction in opioid-related complications were analyzed both individually and together as a measure of overall success. One hundred forty-nine patients were enrolled and 119 were implanted. Average numeric analog scale pain decreased from 6.1 to 4.2 at 1 month and was maintained through month 7 (P <.01) and through month 13 (P <.05). Systemic opioid use was significantly decreased throughout the study (P <.01). Significant reduction in the opioid complication severity index was demonstrated at all 4 follow-up visits (P <.01). Overall success (>/=50% reduction in numeric analog scale pain, use of systemic opioids, or opioid complication severity index) was reported in 83%, 90%, 85%, and 91% of patients at months 1, 2, 3, and 4, respectively. This study demonstrated that patients with refractory cancer pain or intolerable side effects achieved better analgesia when managed with patient-activated intrathecal delivery of morphine sulfate via an implanted delivery system.

Management of spinal infusions in palliative care

Spinal analgesia can provide excellent pain relief for a small group of patients in whom conventional modalities have failed. The role of spinal analgesia in the palliative care setting is discussed and illustrated by the experience at St Gemma's Hospice over a two-year period. Special emphasis is placed on the difficulties that may need to be overcome when using this form of analgesia. The management of spinal infusions can produce some unique problems to the hospice or home care team, but the benefits often far outweight the difficulties.

Comparison of intermittent bolus with continuous infusion of epidural morphine in the treatment of severe cancer pain

Twenty-eight patients with severe pain due to cancer, who could no longer obtain acceptable pain relief from optimised doses of oral opioids, were entered into a study which compared pain relief, satisfaction with pain therapy and estimates of neuropsychological functioning during treatment with spinally administered (i.e., epidural and intrathecal) morphine as either repeated bolus doses or as a continuous infusion. These measures of efficacy and side effects were repeated every 2 weeks until either the patient died (82% of patients), withdrew from the study or were no longer able to complete the tests due to deterioration of their condition. The mean (range) duration of treatment was 169 (6-537) days for those patients receiving continuous infusion and 140 (28-378) days for those patients receiving repeated bolus doses. There was no significant difference in visual analogue pain scores, pain relief scores and satisfaction scores between the bolus and infusion groups. Furthermore, low pain scores and high pain relief scores indicated that both treatment modalities provided effective pain control. Similarly, there was no significant difference between the two groups in the various tests used to assess depression or neuropsychological function (i.e., memory, vigilance, attention and processing). There was a significantly greater degree of dose escalation in patients receiving continuous infusion compared to patients receiving repeated bolus doses. For 6 patients in the infusion group the catheter was sited in the intrathecal space, as the dose requirements by the epidural route exceeded the delivery capacity of the pump. For 4 patients in the bolus group the catheter was similarly sited, due to pain on injection and leakage/blockage.(ABSTRACT TRUNCATED AT 250 WORDS)