In the clinical work of cancer pain management, there are often some misconceptions. These misconceptions may have an impact on the rational use of pain medications. Most of the misconceptions in cancer pain treatment focus on misconceptions about opioids.
Myth 1: It is safer to use non-opioid drugs
In fact, for patients who need long-term pain medication for chronic cancer pain, it is safer to use opioids, and there are no toxic effects on liver, kidney and other organs for long-term use. However, there is a concomitant increased risk for long-term use of NSAIDs. Physicians should then be familiar with the restrictive doses of NSAIDs. According to clinical trials, the upper dose of NSAIDs is generally limited to 1.5-2.0 times the standard recommended dose. When the NSAID dose reaches the restrictive dose, if the pain is still not satisfactorily controlled, only the opioid dose should be increased. Opioid analgesics should be preferred for the treatment of moderate or severe cancer pain.
In 2000, the WHO suggested that “although there are various pharmacological and non-pharmacological treatments for cancer pain, opioid analgesics are essential in the treatment of cancer pain among all pain management methods. For patients with moderate and severe cancer pain, opioid analgesics have an irreplaceable position. Therefore, the International Narcotics Control Board (INCB) emphasizes the need to ensure the availability of opioids in pain management.”
Myth 2: Use painkillers only when the pain is severe
In fact, timely and on-time use of pain medication is safer and more effective, and requires the lowest intensity and dose of pain medication. Cancer pain patients who do not receive effective pain relief treatment for a long time are prone to sympathetic nerve dysfunction related to neuropathic pain caused by pain, which manifests as abnormal pain with nociceptive hypersensitivity and other intractable pain.
Myth 3: Analgesic treatment can partially relieve pain
In fact, the purpose of pain relief treatment is to relieve pain and improve the patient’s quality of life. Pain-free sleep is the minimum requirement of pain relief treatment. In addition to this goal, ideal pain relief treatment should also aim at pain-free rest and pain-free activities to achieve the goal of improving patients’ quality of life in the real sense.
Myth 4: When adverse reactions such as vomiting and sedation occur with opioids, opioids should be stopped immediately
In fact, except for constipation side effects, most of the adverse reactions of opioids are temporary or tolerable. Adverse reactions to opioids, such as vomiting and sedation, generally occur only in the first few days of use, and the symptoms disappear on their own after a few days. Active preventive treatment of opioid adverse reactions can reduce or avoid the occurrence of adverse reactions.
Myth 5: Dulcolax is the safest and most effective painkiller
In fact, WHO has listed dulcolax as a drug not recommended for cancer pain treatment. The pain-relieving effect of dulcolax is only 1/10 of that of morphine. The metabolite desmethyl dulcolax has a long elimination half-life and has potential neurotoxic and nephrotoxic effects. In addition, because of the poor oral absorption rate of dulcolax, it is mostly administered by intramuscular injection. Intramuscular injection itself can produce pain and should not be used for chronic pain treatment such as cancer pain.
Myth 6: The maximum tolerated dose of opioid painkillers should be used only for patients with terminal cancer
In fact, the dose of opioid analgesics varies widely among individuals, and a few patients need opioid doses for pain management. There is no capping effect of opioid analgesics, and if the condition worsens and pain increases, the effectiveness of pain management can be improved by increasing the dose of opioid medication. For any patient with severe pain, regardless of the clinical stage of the tumor and the expected survival time, a large tolerated dose of opioid analgesics can be used to achieve the desired pain relief as long as the pain treatment is needed.
Myth 7: Long-term use of opioid painkillers will inevitably lead to addiction
In fact, the risk of addiction (psychiatric dependence) for cancer pain patients treated with opioids for a long time, especially when administered orally or by transdermal patch on time, is extremely small. In the course of her long-term practice of treating patients with advanced cancer, Professor Sun Yan has encountered only 4 cases of psychiatric dependence in more than 40 years. On average, there is only one case every 10 years, and none of them has occurred since the WHO cancer pain relief was launched in 1990. The risk of psychiatric dependence with opioids reported by Porter abroad is less than 4 per 10,000 (4/11882 cases). All of these facts indicate that opioid addiction in cancer patients is very rare. The development of tolerance or physical dependence on opioids does not imply addiction, nor does it affect the safe continued use of opioids for pain management. Opioid controlled extended-release dosage forms or transdermal administration in a timely manner can avoid excessive peak blood levels, thereby reducing the risk of addiction.
Despite this, the general public, and even some medical professionals, drug suppliers and administrators, remain wary and even fearful of the use of opioids. Results of the National Cancer Pain Management Survey show that the public, medical professionals, and drug supply and management personnel are fearful of the “addictive” nature of opioids. At the same time, national anti-drug campaigns in recent decades have taken hold, with strict policies on narcotic drugs and an emphasis on the consequences of improper opioid use and abuse. Then, while highlighting the negative effects of opioids, it has also created concern and even fear about the proper use of opioids for cancer pain. Misconceptions such as mistakenly equating opioid tolerance with “addiction” also contribute to the fear of opioid pain medications.
Tolerance to opioids is characterized by tolerance to the adverse effects of opioids as the duration of opioid pain relief increases, and the need to increase the dose of opioids to some extent. Drug tolerance is common in cancer treatment and does not affect the continued use of opioid analgesics in patients with cancer pain.
The WHO no longer uses the term “addiction”. The alternative term is “drug dependence”. Physical dependence is not the same as “addiction”, but mental dependence is what people often call “addiction”. Somatic dependence often occurs in cancer pain treatment, and is manifested as a certain degree of physical dependence on opioids after long-term use, and withdrawal symptoms occur when the drug is suddenly interrupted. Somatic dependence and psychiatric dependence are independent of each other in cancer pain treatment. The somatic dependence on opioids for pain management does not affect the continued use of opioid analgesics. In clinical practice, the main reason why cancer pain patients need to use opioid analgesics for a long time or need to increase the dose of opioid analgesics is because of the need for cancer pain treatment, but not because of “addiction”. Patients with cancer pain develop tolerance and physical dependence on opioids, not because they think they have become addicted, which does not affect the safe use of opioid pain medication.
Opioid abuse is the use of opioids for non-medical purposes. Medical addiction, on the other hand, is the psychiatric dependence of a patient due to the irrational use of medication for medical purposes.
In addition, the incidence of opioid “addiction” is related to the drug dosage form, route of administration, and method of administration. Direct intravenous injection results in a sudden increase in blood concentration, which can easily lead to euphoria and toxic reactions, thus easily leading to addiction. In the treatment of chronic pain, the use of controlled and slow release formulations, oral or transdermal administration, and scheduled dosing can avoid excessive peak blood concentrations and keep the active drug in the blood somewhat constant. This standardized approach to medication administration can significantly reduce the risk of addiction while ensuring ideal pain relief treatment.
Myth #8: Opioids, if widely used, are bound to cause abuse
Actively implementing WHO’s three-step cancer pain treatment principles and carrying out publicity and education on the rational use of opioid painkillers will not only enable the majority of cancer pain patients to receive ideal pain treatment, but also avoid or reduce the risk of opioid abuse.
Since the WHO issued the three-step cancer pain relief guidelines in 1992, the global medical consumption of morphine has been on the rise. 2.2 tons of morphine were consumed worldwide in the 1980s, and 22 tons of morphine were consumed worldwide in the 1990s. However, the significant increase in global opioid consumption has not been accompanied by an increase in the risk of opioid abuse.
Myth #9: Once you use opioids, you may need medication for life
In fact, opioid pain medication can be safely discontinued at any time after cancer pain is controlled by the disease and the disappearance of pain. When the daily dose of morphine is 30-60mg, sudden discontinuation of the drug will not cause any accident. For long-term high-dose users, sudden discontinuation may result in end-of-withdrawal syndrome. It is recommended that patients who have been using large amounts of morphine for a long period of time should stop gradually. The dose should be reduced by 25%-50% within the first two days, and then by 25% every two days until the daily dose is reduced to 30-60 mg. When reducing the dose, observe the patient’s pain and the presence of agitation symptoms such as diarrhea, and if the pain score is >3-4, or if there are withdrawal symptoms, the dose should be reduced slowly.
Myth 10: Treating pain with opioids means giving euthanasia
Treatment with opioid painkillers is not euthanasia. On the contrary, using opioid painkillers according to the condition of cancer pain can not only effectively control pain, but also reduce the risk of death due to severe pain, improve the quality of life and effectively prolong the survival of patients. Maefartane reported that a prospective pain survey of 6569 cancer patients in the Northwest of England with up to 8 years of follow-up in 1991-1992 found a mortality rate of 1.55 for patients with localized pain and widespread pain and 2.07 for patients with widespread generalized pain. Deaths from non-disease causes of pain (e.g., car accidents, suicide, homicide, etc.) were also higher (mortality rate of 5.21). The investigators concluded that widespread body pain complained by cancer patients was strongly associated with cancer deaths. According to this result, it is projected that widespread body pain lasting for one day may increase the risk of cancer death by at least 20%, so aggressive pain treatment is associated with reducing the risk of death due to pain and plays an indirect role in prolonging life.
Myth 11: Lung cancer patients cannot use opioids
In fact, patients with lung cancer pain can safely and effectively use opioid painkillers. The crux of people’s doubts about the use of opioid painkillers for lung cancer patients lies in the concern about the respiratory depressant effect of opioids. There is concern that patients with lung cancer and metastatic lung cancer may have low tolerance for opioid pain medications due to poor lung function. Respiratory distress caused by lung disease is a peripheral lesion, i.e. caused by pulmonary lesions, while respiratory depression caused by opioids is a central effect of the drug, i.e. a side effect on central respiratory depression, which generally occurs only in the case of overdose, especially when the peak blood concentration value rises extremely rapidly, such as when large intravenous doses are used, or when the drug accumulates poisoning, such as when renal insufficiency. When opioids are used reasonably in cancer pain patients, adverse reactions of respiratory depression are rare. The main reasons for this are: First, pain is a natural antagonist of the adverse effects of opioid respiratory depression, and patients with severe pain rarely experience respiratory depression with opioid analgesics; second, patients with cancer pain will soon develop tolerance to the side effects of respiratory depression with long-term opioid use.
Myth 12: Narcotic drugs are troublesome to manage, and the fewer varieties the better
In fact, opioids are essential drugs for cancer pain treatment, and the diversity of their types, dosage forms and specifications is conducive to individualized clinical drug administration. . For patients with moderate and severe cancer pain, opioid analgesics have an irreplaceable position. Therefore, the International Narcotics Control Board has emphasized the need to ensure the availability of opioids for pain management. The types and dosage forms of pain medications currently available for clinical use in most hospitals do not meet the needs of all patients, especially those with specific medical conditions. For example, there is a misconception that the availability of opioid-controlled, slow-acting formulations is sufficient. In fact, for most cancer patients, opioid-controlled and extended formulations are needed along with a back-up immediate release agent. The use of opioid immediate-release formulations facilitates rapid titration to the optimal dose for individualized dosing during the initial phase of pain management. During pain management, a standby opioid immediate-release agent can help control sudden or explosive pain.