The literature reveals that up to 58% of patients with Chronic Renal Failure (CRF) have some pain that is difficult to control. Despite this, there is a lack of consensus that addresses its diagnosis and treatment in this type of patients. The pain seems to be generally of musculoskeletal origin, although neuropathic pain is also common. It is according to the degree of renal impairment that certain doses of drugs must be adjusted to avoid the accumulation of active metabolites. To dose we must consider a decreased clearance of the drug (Cl), changes in the volume of distribution (Vd), lower protein binding, threshold to decreased respiratory depression, suggests nephrologist in Delhi.
The use of analgesics in patients with CRF is relatively uncommon, considering the prevalence of severe pain in this population. Paracetamol is a safe alternative in this type of patients, and yet it is prescribed very little. The frequency of prescription of NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) impresses with being inappropriately high, and the precaution of restricting them in patients with a Glomerular Filtration (GFR) less than 35 ml / minute is rarely taken to avoid further deteriorating renal function. The opioids that are frequently prescribed are of the weak type, and some have inadequate pharmacokinetic properties for patients with kidney disease, says best nephrologist in Delhi.
To treat pain in a patient with CRF, several factors must be considered; the degree of insufficiency, drug interactions and comorbidities. Opioids should be used conservatively and with low titres. The use of NSAIDs is not recommended chronically, but they may have a role in the treatment of renal colic by inhibiting the synthesis of prostaglandins. Its use should not exceed 7 days. In post-dialysis patients kidney specialist in Delhi suggests to start the dose of gabapentin at 100 mg every other day, and pregabalin can be started at doses as low as 25 mg every other day.
It is estimated that up to 50% of patients with CRF have diabetes mellitus. Of these, one third suffer from diabetic neuropathy. Gabapentinoids are not only useful in the treatment of this, they have also been shown to play an important role in other symptoms, such as pruritus and insomnia.
Joint pain is another common problem in patients with CRF. They often have severe shoulder pain without a clear etiology. One hypothesis is that pain is caused by accumulation of B2 microglobulin in the joint. In those patients in whom the pharmacological treatment is not successful, an arthroscopic synovectomy may be a good option. B2 microglobulin deposition can also cause mononeuropathies, including Carpal Tunnel Syndrome (STC), caused by extrinsic compression of the median nerve, which often requires surgical decompression.
Next, best kidney specialist in Delhi will talk about some of the frequently used analgesics and their implications in the IRC:
Paracetamol: It is a powerful analgesic and antipyretic. It is the analgesic of choice in patients with kidney disease (except in those who also have liver failure). Its maximum dose is 3000 mg per day. It usually does not require adjustment according to the glomerular filtration rate (GFR), although some top kidney specialist in Delhi recommends spacing doses every 8 hours when GFR is <10 mL / min.
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): May decrease opioid requirements by up to 30%. However, due to its gastrointestinal and renal adverse effects its prolonged use in patients with CRF should be avoided. If your prescription is necessary, it should be limited to no more than 7 days, always monitoring the renal function suggests top nephrologist in Delhi.
Morphine: It is the most widely studied opioid analgesic in kidney disease. It is an agonist of the µ receptors. It causes pain relief through its µ1 agony and respiratory depression through µ2. It is metabolized in the liver to various metabolites. Of these, morphine-6-glucoronide is approximately 10 times more potent than morphine. It accumulates in the CRF causing respiratory depression and depression of the Central Nervous System (CNS), since once it crosses the blood brain barrier (BHE) the effect persists for several days after the drug has been suspended and even after a hemodialysis. It is recommended by kidney doctor in Delhi to reduce the dose by 25%, 50% and 75% in patients with CKD stages 3,4 and 5, respectively.
Codeine: A series of active metabolites (codeine-6-glucuronide, norcodeine, morphine, M3G, M6G, and normorphine) are metabolized via the liver, which are excreted via the kidneys. Its half-life is prolonged up to 5 times in patients requiring hemodialysis. Coidein and its metabolites accumulate in the IR and cause hypotension and respiratory depression.
Fentanyl: It is rapidly metabolized via liver to inactive metabolites. It does not accumulate significantly in the IRC, so it is a safe option. No dose reduction is necessary.
Tramadol: It is an opioid analgesic that also inhibits the re-capture of serotonin and norepinephrine. It is effective in both nociceptive pain and neuropathic pain and has the advantage of producing less sedation and respiratory depression than the rest of opioids. A common adverse effect is nausea. A rare but important effect is seizures, especially in patients taking medications that lower the seizure threshold, such as serotonin reuptake inhibitors. It can also cause serotonin syndrome. In advanced CRF, the elimination half-life may even double, so the dose should be reduced to 200 mg / day in patients with a GFR <30 ml / min, and to 50 mg / day if the GFR is <10 ml / min. Tramadol is eliminated with dialysis, so it should be administered after it.