To evaluate the role of oral ketamine as an adjuvant to oral morphine in cancer patients experiencing neuropathic pain, 9 cancer patients (5 men, 4 women) taking maximally tolerated doses of either morphine, amitriptyline, sodium valproate, or a combination of these drugs for intractable neuropathic pain, and reporting a pain score of >6 on a 0-10 scale, were studied prospectively to evaluate analgesia and adverse effects. Ketamine in the dose of 0.5 mg/kg body weight three times daily was added to the existing drug regimen. Patients were taught to maintain a pain diary wherein they daily recorded their pain, sedation, and vomiting scores, and other side effects. A decrease of more than 3 from the baseline in the average pain score, or a score of < or =3 was taken as a successful response. Seven patients exhibited a decrease of more than 3. Four patients experienced nausea, of which one had vomiting. Two developed loss of appetite. Eight patients reported drowsiness during the first two weeks of therapy (P = 0.001), and this gradually improved over the next two weeks in 5 of these 8 patients. Three patients withdrew from the study, two owing to excessive sedation and another due to a "feeling of unreality." None of the patients reported visual or auditory hallucinations. This experience suggests that low dose oral ketamine is beneficial and effective in the management of intractable neuropathic pain in patients with advanced cancer. However, its utility is limited in some patients by the adverse effects that accompany its use.

We prospectively studied 30 healthy female patients undergoing intracavitory brachytherapy applicator insertion for carcinoma of the cervix under spinal anaesthesia. Patients were randomly allocated to receive either intrathecal bupivacaine 10 mg alone or bupivacaine 7.5 mg combined with preservative-free ketamine 25 mg. Spinal block onset, maximum sensory level, duration of blockade, haemodynamic variables, postoperative analgesic requirements and adverse events were recorded. Onset of sensory and motor block and duration of spinal analgesia were comparable between groups. Duration of motor blockade was shorter (p 0.0416) and requirement for intravenous fluids in the peri-operative period was less (p 0.0159) in the ketamine group. Significantly more patients in the ketamine group had adverse events, such as sedation, dizziness, nystagmus,`strange feelings' and postoperative nausea and vomiting. Although the addition of ketamine to spinal bupivacaine had local anaesthetic sparing effects, it did not provide extended postoperative analgesia or decrease the postoperative analgesic requirements. Moreover, the central adverse effects of ketamine limit its spinal application. Reducing the dose of bupivacaine used in spinal anaesthesia helps to achieve rapid anaesthetic recovery but may result in anaesthetic failure [1]. Intrathecal adjuncts, such as opioids [2], vasoconstrictors [3], alpha-2 agonists [4], and neostigmine [5] are often added to enhance spinal anaesthesia. Even though these adjuncts are effective in improving the efficacy of low-dose spinal anaesthesia, their use is limited because of side-effects [2±5].Ketamine is an anaesthetic agent with potent analgesic properties. Its mode of action includes noncompetitive antagonism at N-methyl d-aspartate (NMDA) receptors and a local anaesthetic effect [6]. Intrathecal ketamine has been evaluated as a sole anaesthetic agent [7,8], but psychomimetic disturbances and inadequate analgesia precluded its use for this purpose. In this study, we evaluated the effects of intrathecal ketamine added to a small dose of spinal bupivacaine in patients with carcinoma of the cervix undergoing intracavitory brachytherapy applicator insertion. MethodsAfter obtaining approval from our Institutional Ethics Committee and informed patient consent, we enrolled 60 female, ASA physical status I or II patients with carcinoma of the cervix undergoing intracavitory brachytherapy implants (ovoids and tandems) insertion under spinal anaesthesia. Patients were randomly allocated to receive q 2000 Blackwell Science Ltd 899 either intrathecal hyperbaric bupivacaine 10 mg alone (0.5% Sensorcaine in 8.25% dextrose; Astra-IDL, India) or bupivacaine 7.5 mg with preservative-free ketamine 25 mg (Aneket 5%, Neon Laboratories, India). The patients and the doctor who observed the patients in the recovery room were blinded to the treatment.The Verbal Numerical Scores (VNS) system for assessment of pain was explained during the pre-operative visit. Patients were fasted for 6 h pre-operatively and premed...

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