Gabapentin, an Adjuvant Treatment for Neuropathic Pain in a Cancer Hospital. References

Transcription

1 82 Letters Vol. 20 No. 2 August 2000 Fig. 1. Cost evolution of morphine. Daily dose 180 mg. 1 US$ 1$. SR, sustained release; IR, immediate release. Magistral morphine: mean value (US$155); standard deviation 52, min. 65, max IR morphine #2: wholesale cost ( 500 pills). Source: Manual Farmacéutico, Editorial AlfaBeta, ISSN the magistral preparations. This may have been the first positive result of the competitiveness in the opioid market. The second positive result of this competitiveness might have been the sharp and significant decrease in price of a second commercial IR morphine. The price of this drug was initially high and was recently set at a similar level as the international price and lower than the average cost of magistral prescriptions. This price reduction was probably induced by the appearance of methadone in the Argentine market, which was the least expensive analgesic option. We hope that this last change will generate a third positive fact in the near future: the reduction of the price of methadone to its international value. These analyses indicates that quality products can become available, and also favor the more inexpensive one. The search for the best cost/benefit ratio, its promotion and diffusion, is an ethical responsibility for all of us who are in clinical and teaching positions and wish the most convenient treatments for our patients. In Argentina, the efforts to disseminate this concept, the implementation of clinical and teaching programs based on WHO and Pan- American Health Organization recommendations, and the free competitiveness of the pharmaceutical companies in a liberal market have achieved substantial changes in the availability of low cost opioids. Roberto Wenk, MD Programa Argentino de Medicina Paliativa- Mariela Bertolino, MD Unidad de Cuidados Paliativos Hospital Tornu- Juan Pussetto, MD Programa Argentino de Medicina Paliativa- Buenos Aires, Argentina PII S (00) References 1. Organizaciòn Mundial de al Salud. Alivio del dolor en el cancer; con une guia sobre la disponsibilidad de opioides. Segunda edicion. Ginebra: OMS, Mercadante S. Costs are a further barrier to cancer pain management. J Pain Symptom Manage, 1999, 18: De Lima L, Bruera E, Joranson D, Vanegas G, Cepeda S, Quesada L. Opioid availability in Latin America: The Santo Domingo Report, Progress Since the Declaration of Florianopolis. J Pain Symptom Manage, 1997, 13: Gabapentin, an Adjuvant Treatment for Neuropathic Pain in a Cancer Hospital To the Editor: In a recent article by Caraceni et al., 1 gabapentin was judged to be efficacious as an adjuvant analgesic for neuropathic cancer pain in 20 out of 22 patients. We report on our experi-

2 Vol. 20 No. 2 August 2000 Letters 83 ence of gabapentin, which was associated with a much lower incidence of efficacy. We carried out a retrospective review of the case notes of 20 patients who had been prescribed gabapentin since January 1999 (Table 1). In our review, only 9 (45%) patients reported a significant improvement in their pain following administration of gabapentin. For a further 5 patients, it was difficult to evaluate the efficacy of gabapentin due to the concomitant use of other neuropathic agents, such as amitriptyline, tramadol, and opioids. In addition, 6 patients out of the 20 who were prescribed gabapentin developed severe enough to warrant the discontinuation of the drug. The most common were dizziness and nausea. As systematic reviews have shown little difference in the efficacy and side effect profile of antidepressants and anticonvulsants, 2 good quality studies comparing the efficacy and side effect profile of gabapentin with these neuropathic agents are needed. The findings of these studies will be important because the high cost of gabapentin frequently limits its use in hospital and general practice. Anne Chandler, BSc (Hons), RGN, Onc Cert Pain Research Nurse John E. Williams, MB BS, FRCA Consultant in Anesthesia and Pain Management Royal Marsden Hospital London, United Kingdom PII S (00) References 1. Caraceni A, Zecca E, Martini C, DeConno F. Gabapentin as an adjuvant to opioid analgesia for neuropathic cancer pain. J Pain Symptom Manage 1999;17: McQuay H, Moore A. Anticonvulsant drugs. Antidepressants in neuropathic pain. In: An Evidence Based Resource for Pain Relief. Oxford: Oxford University Press, 1998.

3 84 Letters Vol. 20 No. 2 August 2000 Table 1 Use of Gabapentin in a Cancer Hospital 1 Myeloma Postherpetic Neuralgia T4/T5 distribution Methadone Dothiepin 2 Endometrial carcinoma Neuropathic pain leg Hydromorphone 3 Prostatic carcinoma Neuropathic pain leg Opioids 4 Neurofibroma Neuropathic pain back, leg, and arm 5 Sarcoma Phantom pain post limb amputation 6 Pyriform fossa carcinoma Neuropathic pain post radiotherapy Diazepam 7 Tongue carcinoma Neuropathic pain Diclofenac MST Naproxen 300 mg tds Erectile dysfunction Discontinued due to 300 mg day 1 2 Dizzy and confused Discontinued due to 300 mg tds Pain significantly improved, able to reduce opioids 300 mg tds Dizzy and sick Discontinued due to 300 mg tds Tremor, dose reduced to 100 mg tds Pain improved, efficacy also related to increased dose of morphine and amitriptyline in addition to gabapentin 300 mg tds Pain significantly improved, able to reduce opioids 300 mg tds Pain improved, efficacy also related to morphine and dose increase of amitriptyline 8 Soft palate tumor Neuropathic pain Opioids 300 mg tds Pain much improved Diclofenac Opioids Paracetmol 9 Mesothelioma Pain in back and axillary area Codydramol Sevredol 300 mg tds Dizzy, nauseated Stopped both gabapentin and tramadol due to side effects. Pain improved without need for further

4 Vol. 20 No. 2 August 2000 Letters 85 Table 1 10 Mesothelioma Radicular pain 300 mg tds Pain significantly better 11 Sarcoma Amputation, phantom limb pain 12 Pelvic sarcoma Radicular pain leg Dothiepin Dihydrocodeine 13 Carcinoma of the bladder Radicular pain sciatic distribution 14 Carcinoma of the breast Radiation-induced Brachial plexopathy 300 mg tds Erectile dysfunction may also be related to amitriptyline Pain controlled, efficacy also related to use of other s 400 mg tds Pain much improved by addition of gabapentin 300 mg tds Pain improved 300 mg tds Lost balance at 400 mg tds dose maintained at 300 mg Pain improved 15 Carcinoma of the cervix Radicular pain L4 600 mg tds Difficult to evaluate efficacy nerve root of gabapentin due to Steroids concomitant use of other s 16 Carcinoma of the breast Postmastectomy pain 300 mg tds Dizzy Stopped due to dizziness 17 Leukemia Postherpetic neuralgia 300 mg tds increased to 800 mg tds Pain improved significantly at 400 mg tds. Dose increased to 800 mg following pain flare up. No subsequent improvement therefore dose reduced to 400 mg tds

5 86 Letters Vol. 20 No. 2 August 2000 Table 1 18 Neurofibroma Neuropathic pain Diazepam 19 Head and neck tumor Mixed nociceptive and neuropathic pain Codeine 20 Lymphoma Pain coccyx? cause Hydromorphone Other opioids Naproxen 300 mg tds Dizzy and vomiting Gabapentin stopped due to start at 100 mg tds Pain improved, to continue increasing dose 500 mg tds Difficult to assess effectiveness - pain continues to be an ongoing problem Overall outcome after gabapentin use (n 20) Patient numbers Percentage Effective 9 45% Possibly effective 5 25% Discontinued due to 6 24%