Amitriptyline effectively relieves neuropathic pain following treatment of breast cancer

Pain Processing: Paradoxes and Predictions

During the last 25 years, there have been substantial advances in our understanding of the physiology and pathophysiology of pain. The development of animal models that more closely mimic clinical pain in humans has helped elucidate the putative mechanisms by which chronic pain develops and is maintained. However, our increased understanding of the neurobiology of pain has not translated into breakthrough treatments for pain management. As such, chronic pain is still primarily managed by drugs whose primary indication does not include pain (eg, antidepressants, anticonvulsants, antiarrhythmics, local anesthetics). These adjuvant analgesics have come into favor despite the fact that the mechanisms through which these drugs provide pain relief remain either largely unknown or are not selective for a single target. Moreover, the efficacy of adjuvant analgesics in animal models of pain is often validated only after case studies or clinical trials have been reported. This retrospective validation of "novel" analgesics in animal models of pain raises a question of the predictive validity of these models. This article reviews the use of several adjuvant and standard analgesics currently used to treat difficult-to-manage pain. What can these drugs teach us about the development of novel pain medicines? Within this context, the use of animal models of pain to predict analgesic efficacy in clinical pain conditions is considered.

Palliative care in inflammatory bowel disease: an evidence-based approach

The management of the patient with inflammatory bowel disease (IBD) is challenging for both the physician and the patient. IBD imposes both a physical and emotional burden on patients' lives. Palliative care is important for IBD patients because it focuses on improving quality of life. While palliative care does not change the natural history of the disease, it provides relief from pain and other distressing symptoms. This article focuses on various aspects of care for IBD patients including pain control, management of oral and skin ulcerations, stomal problems in IBD patients, control of nausea and vomiting, management of chronic diarrhea and pruritus ani, evaluation of anemia, treatment of steroid-related bone disease, and treatment of psychological problems associated with IBD. Each of these areas is reviewed using an evidence-based approach. Evidence in category A refers to evidence from clinical trials that are randomized and well controlled. Category B Evidence refers to evidence from cohort or case-controlled studies. Category C is evidence from case reports or flawed clinical trials. Evidence from category D is limited to the clinical experience of the authors. Evidence labelled as category E refers to situations where there is insufficient evidence available to form an opinion. Algorithms for management of pain and nausea in IBD patients are presented.

Headache in Meniere's disease

OBJECTIVE

We examined headache in 86 patients with severe or moderately severe Meniere's disease (MD) or with Meniere's syndrome (MS) chosen for intratympanic gentamicin treatment. Forty-five patients with vestibular neuronitis (VN) served as a control group.

METHODS

In addition to a clinical examination, the patients filled out a questionnaire concerning their headache.

RESULTS

Altogether 60 MD patients (70%) and 26 VN patients (58%) reported headache. Headache was severe in 35 MD patients (58%), moderate in 16 patients (27%) and slight in nine MD patients (15%), and as a whole more severe than that of the VN patients (P < 0.01). The MD patients exhibited significantly more occipital (P < 0.005) and neck headache (P < 0.005) than the VN patients. Analgesics had been used by 82%, antidepressants by 35%, sumatriptan by 13% and carbamazepine and/or amitriptyline by 12% of the MD patients suffering from headache. Pain relief was reported as good by 27%, satisfactory by 60%, poor by 5% of the MD patients and 8% could not rate the pain relief. In this study migraine was diagnosed in 5 MD patients.

CONCLUSION

It is concluded that MD is associated with headache that can be handicapping, and tricyclic antidepressants with pain alleviating medication is often needed to treat the headache in MD whereas sumatriptan did not alleviate the headache of the non-migraine patients.

A retrospective cohort study of post mastectomy pain syndrome

Post mastectomy pain syndrome is a condition which can occur following breast surgery and has until recently been regarded as uncommon. Recent reports have suggested that it may affect 20% or more of women following mastectomy. The symptoms are distressing and may be difficult to treat however treatment for neuropathic pain can be successful. This paper reports a retrospective cohort of consecutive mastectomy cases over a six year period in one region of whom 511 survivors were traced and eligible for survey. A total of 408 completed a questionnaire survey which revealed that 175 (43%) had ever suffered from postmastectomy pain syndrome and 119 (29%) reported current symptoms although the majority were decreasing in intensity. A striking finding was the very high cumulative prevalence in younger women (65%) decreasing to 26% in the over 70 year group. The details of the onset, frequency and intensity of symptoms are described along with their natural history. The age effect on the frequency of the syndrome influences the marital status, employment status, housing, and educational status of those who report typical symptoms. Body weight and height are also associated with the frequency of post mastectomy pain syndrome. Relationship between the frequency of post mastectomy pain syndrome and radiotherapy, chemotherapy and the use of tamoxifen are difficult to unravel because of the combinations of pre and post operative treatments received confounded by age. The implications of a much higher frequency of post mastectomy pain are discussed with regard to management and counselling. The high frequency of the syndrome in the younger women is important and possible explanations are explored.

Measurement of pain

Pain is a personal, subjective experience influenced by cultural learning, the meaning of the situation, attention, and other psychologic variables. Approaches to the measurement of pain include verbal and numeric self-rating scales, behavioral observation scales, and physiologic responses. The complex nature of the experience of pain suggests that measurements from these domains may not always show high concordance. Because pain is subjective, patients' self-reports provide the most valid measure of the experience. The VAS and the MPQ are probably the most frequently used self-rating instruments for the measurement of pain in clinical and research settings. The MPQ is designed to assess the multidimensional nature of pain experience and has been demonstrated to be a reliable, valid, and consistent measurement tool. A short-form MPQ is available for use in specific research settings when the time to obtain information from patients is limited and when more information than simply the intensity of pain is desired. The DDS was developed using sophisticated psychophysical techniques and was designed to measure separately the sensory and unpleasantness dimensions of pain. It has been shown to be a valid and reliable measurement of pain with ratio-scaling properties and has recently been used in a clinical setting. Behavioral approaches to the measurement of pain also provide valuable data. Further development and refinement of pain measurement techniques will lead to increasingly accurate tools with greater predictive powers.

Risk factors for pain after mastectomy/lumpectomy

PURPOSE

Careful study of risk factors that predispose an individual to developing postmastectomy pain (PMP) after breast cancer surgery has not been reported. This study examined potential risk factors for PMP including demographic, disease, and treatment variables, as well as surgical factors, such as surgical technique and number of lymph nodes removed.

DESCRIPTION OF THE STUDY

Data were collected via telephone interviews and review of medical records. Pain was assessed using the Brief Pain Inventory. The sample included 134 breast cancer survivors who were a mean age of 55 years (SD = 9) and a mean of 35 months postsurgery (SD = 19).

RESULTS

Women with PMP (n = 36) were not significantly different from women without PMP (n = 98) on demographic, disease, treatment, or surgical variables. PMP intensity was not significantly associated with age at diagnosis, time postsurgery, or time post-treatment. Contrary to expectation, PMP was found in women postlumpectomy without axillary dissection, women whose intercostobrachial nerve was spared, and women without documented postoperative complications.

CLINICAL IMPLICATIONS

Findings suggest that cases of PMP cannot uniformly be identified based on the presence or absence of certain factors. Findings also underscore the need to screen all women for PMP after breast cancer surgery, particularly given the availability of effective pain management therapies.

Postmastectomy/postlumpectomy pain in breast cancer survivors

Few studies have focused on careful assessment of postmastectomy pain (PMP); a chronic neuropathic pain syndrome that can affect women postlumpectomy or postmastectomy for breast cancer (BC). Study aims were to determine the prevalence of PMP in an outpatient sample of breast cancer survivors (BCS), describe subjective and objective characteristics of PMP, and examine the relationship between PMP and quality of life. Breast cancer survivors (n = 134) participated in telephone interviews, and those reporting PMP (n = 36) were invited to a pain center for further evaluation and treatment. Results show PMP is a distinct, chronic, pain syndrome affecting 27% of BCS. Findings support the need for clinical trials evaluating the effectiveness of nonpharmacological or cognitive behavioral therapies in alleviating mild to moderate PMP.

Food intake and the presystemic metabolism of single doses of amitriptyline and nortriptyline

The influence of food on presystemic metabolism of single doses of amitriptyline (AMI) and nortriptyline (NT) was examined. In randomised order 25 mg tablets of each drug was given to 9 healthy, female volunteers both in the fasting state and together with a standardised breakfast. Concentrations of the drugs and of their dealkylated, hydroxylated and conjugated metabolites were measured by gas chromatography--mass spectrometry (AMI experiment) or high-pressure liquid chromatography (NT experiment). Standard pharmacokinetic parameters were calculated. Food intake did not consistently or significantly influence the bioavailability of either AMI or NT, nor the demethylation of AMI, nor the hydroxylation or the primary or secondary conjugation of NT. There were large interindividual changes in AUC of AMI after food (+94% to -44%). A significant negative correlation between AUC of AMI but not of NT during fasting conditions and per cent change in AUC after food was found (r = -0.72, P = 0.029). The implication of this (negative) correlation for an individual patient might be to keep the intake of the drug in standardised relation to food to avoid undue heavy changes in drug concentration, which might just occur with a change in time relation between intake of drug and food. From a mechanistic view the results argue against a direct and selective influence of food on the presystemic oxidation and conjugation of weakly basic drugs but does not exclude that food may reduce the presystemic metabolism of some such drugs indirectly, by enhancing their rate of hepatic delivery. Presentation of data from food interaction studies should not be restricted to general descriptions. It seems equally important to present the variability of individual data to allow inspection of the extent and direction of effects. This should be of interest for patient, prescriber as well as the regulatory agency.

Differential effects of amitriptyline on perception of somatic and visceral stimulation in healthy humans

Tricyclic antidepressants treat chronic pain both in patients with somatic illness and with functional bowel disorders. We compared the effects of amitriptyline on perception of cutaneous and gastrointestinal stimulation to assess differential analgesic effects of tricyclics on somatic and visceral pain. Cutaneous electrical stimulation and rectal and esophageal distension were performed before and after 21 days of double-blind 50 mg amitriptyline vs. placebo in healthy volunteers. Amitriptyline increased currents that elicited cutaneous threshold, moderate discomfort, and moderate pain compared with basal (P < 0.05), whereas placebo had no effect. Amitriptyline had no effect on perception of rectal and esophageal distension and did not alter luminal compliance; thus the lack of effect on perception is not due to altered visceral elastic wall properties. In conclusion, amitriptyline reduces perception of cutaneous stimulation but does not alter visceral perception or compliance. This investigation demonstrates differential effects of tricyclics on somatic and visceral afferent function in healthy humans and provides insight into mechanisms of action in chronic pain both from somatic disease and from functional bowel disorders.

Pain and other symptoms during the first year after radical and conservative surgery for breast cancer

This study assessed pain, neurological symptoms, oedema of the ipsilateral arm, anxiety and depression occurring in women treated surgically for breast cancer, the impact of these symptoms on daily life and how they evolved during the 1 year follow-up. Ninety-three consecutive patients with non-metastasised breast cancer who were treated during 1993-94 were examined before surgery and after 1, 6 and 12 months. They were asked about pain, neurological symptoms and oedema in the breast scar region and/or ipsilateral arm. Sensory testing was performed, and gripping force and the circumference of the arm were measured. Anxiety and depression were evaluated. One year after surgery, 80% of the women had treatment-related symptoms in the breast scar region and virtually all patients had symptoms in the ipsilateral arm. The incidence of chronic post-treatment pain was higher after conservative surgery than after radical surgery (breast area: 33% vs 17%, NS; ipsilateral arm: 23% vs 13%, NS). Numbness occurred in 75% and oedema of the ipsilateral arm in over 30% of the patients after both radical and conservative surgery. Phantom sensations in the breast were reported by 25% of the patients. No difference in psychic morbidity was detected after the two types of surgery. Both the anxiety and depression scores were highest before surgery, decreasing with time, and were significantly correlated with preoperative stressful events.