Fig. 4.19 This small painful ischaemic ulcer on the heel of a 90-year-old woman healed in 9 weeks following angioplasty.
foot, particularly at night. It is important to control this pain.
• An opioid such as dihydrocodeine, alone (30 mg every 4-6 h) or in combination with a non-opioid analgesic, e.g. co-dydramol (dihydrocodeine 10 mg, paracetamol 500 mg, two tablets every 4-6 h) may be useful in moderate pain
• Tramadol (50-100 mg 4-6 hourly) is an opioid derivative, which is often less sedating and less constipating than codeine
• Tricyclic antidepressants, for example dothiepin 50100 mg at night, are useful at relieving rest pain in bed
• When pain is severe, it is important to give regular morphine therapy. Initially it is best to start with a short-acting preparation taken 4-hourly, and the patient can quickly titrate the dose necessary to relieve pain. After this, it is possible to advance to the modified slow-
release preparations devised for twice-daily administration such as 10-20 mg every 12 h, if no other analgesic or paracetamol has been previously prescribed. However, if it is replacing a weaker opioid analgesic, for example co-dydramol, the initial dose should be 20-30 mg every 12 h. The doses should be gradually increased but the frequency kept at every 12 h. If breakthrough pain occurs between the 12-hourly doses, then morphine, as oral solution (Oramorph 5-20 mg every 4 h) or standard formulation tablets such as Sevredol 10-50 mg every 4 h, can be given
• Beware of respiratory depression, to which diabetic patients with autonomic neuropathy can be susceptible. One of our patients with severe autonomic neuropathy underwent marked respiratory depression when she took dihydrocodeine phosphate and almost stopped breathing
• Chemical sympathectomy by paravertebral injection of phenol is also used to relieve rest pain, although it does not increase peripheral blood flow.
Opiates will be retained by patients in renal failure, often leading to drowsiness, and the dose will need to be suitably reduced.
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