Medication For Persistent Pain: Opioid Pain Medications

What are Opioid Pain Medications?

Opioid pain medications are a class of drugs that are primarily used to manage moderate to severe pain. They work by binding to opioid receptors in the brain, spinal cord, and other areas of the body, reducing the perception of pain. Opioids are effective in controlling pain, but they also carry a risk of dependence, addiction, and side effects such as drowsiness, constipation, and respiratory depression.

What are Atypical Opioids like Buprenorphine, Tramadol, or Tapentadol?

Atypical opioids, such as Buprenorphine, Tramadol, and Tapentadol, are a unique class of opioid medications that differ from traditional opioids in their mechanism of action and side effect profiles. While they are still opioids and can manage pain, they have certain characteristics that can reduce the risk of addiction or offer other therapeutic benefits.

Buprenorphine

This opioid drug is often used for chronic pain management and opioid addiction treatment (e.g., in medications like Suboxone, which combines buprenorphine with naloxone to reduce abuse potential).

Buprenorphine has a “ceiling effect” for respiratory depression, meaning after a certain dose, the risk of dangerous breathing problems doesn’t increase significantly, making it safer for long-term use. Despite being considered safer, it can still lead to dependence and has a risk of withdrawal symptoms if stopped abruptly.

Tramadol

Tramadol is generally used for moderate pain, often in cases of musculoskeletal pain or after surgery. It has a lower potential for abuse compared to stronger opioids. It can be effective for certain types of pain (such as neuropathic pain) that don’t respond well to traditional opioids.

However, it still carries a risk of dependence, and it has additional effects on serotonin and norepinephrine that can also increase the risk of seizures or serotonin syndrome, especially when taken with other medications affecting serotonin.

Tapentadol

This medication is used for managing moderate to severe acute pain or chronic pain, particularly in conditions like diabetic neuropathy.

Compared to traditional opioids, tapentadol may cause less nausea and constipation, common side effects of opioids. It also has a lower potential for abuse compared to stronger opioids. However, tapentadol can still cause respiratory depression, dependence, and abuse, but it offers some advantages in terms of fewer side effects and better pain control in certain situations. They also do not have a serotonergic effect, making them safer to combine with other medications that elevate serotonin levels such as various antidepressant medications.

These atypical opioids are often chosen for specific cases where they offer benefits over traditional opioids, particularly in terms of safety and side effects. However, they still need to be used cautiously, given their potential for addiction and other risks.

What are Typical Opioids like Morphine, Oxycodone, and Codeine?

Typical opioids like morphine, oxycodone, and codeine are part of a class of drugs known as full opioid agonists. This means that these drugs work by binding to mu-opioid receptors in the brain and spinal cord to provide pain relief. They are highly effective at managing moderate to severe pain but carry a significant risk of side effects, dependence, and addiction.

Morphine

This medication is commonly used for severe pain, especially in settings like post-surgical care, cancer pain, or palliative care. It is a reliable, widely studied opioid that effectively manages severe pain, and it is available in both short-acting and long-acting forms (e.g., sustained-release morphine for chronic pain).

Morphine has a high risk of tolerance, dependence, and addiction, especially with long-term use; it can cause common opioid-related side effects such as drowsiness, constipation, and nausea.

Oxycodone

Oxycodone is used for moderate to severe pain and is available as an immediate-release formulation (e.g., OxyIR) and an extended-release form (OxyContin), often prescribed for chronic pain conditions. It can be used in combination with non-opioid pain relievers to enhance its pain-relieving effects.

That said, oxycodone is associated with a high potential for misuse, addiction, and overdose, particularly with long-term use or misuse of the extended-release forms.

Codeine

Codeine is used for mild to moderate pain and is often combined with other medications or in cough syrups for its cough-suppressing properties.

Less potent than stronger opioids, codeine is useful for mild pain. It is less likely to cause severe respiratory depression at therapeutic doses.

However, its pain-relieving effects are dependent on its metabolism to morphine, which varies between individuals. Some people metabolise codeine very quickly, leading to potential toxicity, while others don’t metabolise it well, meaning they don’t get adequate pain relief. It still carries the risk of addiction and side effects, especially in higher doses.

These opioids are typically used under close medical supervision due to their strong potential for abuse and serious side effects, particularly respiratory depression and overdose, which can be life-threatening.

What do Opioid Pain Medications Treat?

Opioid pain medications are primarily used to treat moderate to severe pain, especially in cases where other pain relievers may not be effective. Their use is generally reserved for conditions that cause intense or high levels of pain.

Cancer Pain

Opioids are a cornerstone of pain management in cancer patients, especially for those with advanced or metastatic cancer. They help manage pain caused by tumours pressing on organs, bones, or nerves.

Opioids are used in end-of-life care to provide comfort and alleviate suffering from chronic pain, particularly in hospice settings.

Intense Acute Pain

Opioids are often used after surgery to manage pain during recovery, particularly in major surgeries like joint replacements, abdominal surgeries, or heart surgeries. They may be prescribed for pain relief following accidents, fractures, burns, or other significant injuries or for severe acute conditions like kidney stones, acute pancreatitis, or severe migraines, opioids can provide rapid pain relief when other medications are insufficient.

Neuropathic Pain

While opioids are generally less effective for nerve pain than for other types of pain, they may be used in certain situations when other treatments, such as anticonvulsants or antidepressants, fail. Neuropathic conditions treated with opioids include postherpetic neuralgia, diabetic neuropathy, or neuropathic pain related to damage to the spinal cord or conditions causing acute neuropathic pain such as trauma or surgery.

Post-Trauma or Post-Surgical Chronic Pain

For individuals who develop chronic pain after surgery or injury, opioids may be used as part of a pain management strategy, particularly in cases like amputation or phantom limb pain or post-surgical pain syndromes.

Severe Musculoskeletal Pain and Chronic Non-Cancer Pain

In cases of osteoarthritis or rheumatoid arthritis, where pain is severe and other treatments have failed, opioids may be used for temporary relief. This class of drugs may also be used for short-term relief in severe cases of back pain, particularly if the pain is disabling.

For some pain conditions, such as headaches, fibromyalgia, chronic abdominal pain and certain types of neuropathic pain, opioids are generally not the best option because they are less effective and pose high risks compared to other treatments.They can lead to worsening of pain in the long term due to a phenomenon known as opioid induced hyperalgesia.

Note that while opioids are effective for many types of severe pain, they are not typically recommended for chronic non-cancer pain unless absolutely necessary, due to the risks of tolerance, dependence, and addiction.

POSITION STATEMENT BY THE FACULTY OF PAIN MEDICINE, AUSTRALIA (PS01(PM) 2021)

The Faculty of Pain Medicine (FPM) recognises that opioids are widely and often inappropriately prescribed for Chronic Non-Cancer Pain despite the lack of clear evidence of efficacy.

The FPM also recognises the changed regulatory environment introduced in Australia by the TGA in 2020, specifically:

“[Modified-release opioid product] is indicated for the management of severe pain where

• other treatment options have failed, are contraindicated, not tolerated or are otherwise inappropriate to provide sufficient management of pain, and

• the pain is opioid-responsive, and

• requires daily, continuous, long term treatment.

“[Modified-release opioid product] is NOT indicated for use in chronic non-cancer pain other than in exceptional circumstances.”

The FPM interprets “exceptional circumstances” in this context to denote:

• Severe pain,

– for which other treatment options have failed, are contraindicated, not tolerated or are otherwise inappropriate to provide sufficient management,

and

– which has been shown to be opioid-responsive

The alternative treatment options include non-opioid medications, physical therapy, psychological therapy, lifestyle changes, pain management programs, surgery (if appropriate) and pain interventions.

THE OPIOID CONTRACT

If opioids are considered for management of chronic non-cancer pain in exceptional circumstances, certain principles are followed:

• There is only one prescriber (usually the general practitioner).
• The medication is dispensed from the same pharmacy every time.
• There are no repeat scripts.
• The total maximum dose of the opioid is capped at no more than 120mg Morphine Equivalent per day.
• The medication is used as prescribed with no self escalation of the dose.
• The medication is used for the purposes of managing chronic pain and not other reasons such as managing sleep and anxiety.
• If the patient develops opioid tolerance, then the medication is weaned as opposed to increasing doses above 120mg morphine equivalent per day.
• The patient is reviewed by a Pain specialist every 12 months to ensure continuation of the opioid is appropriate.
• The prescribing practitioner regularly reviews the patient for opioid responsiveness and opioid related harm. If there are any signs of poor responsiveness or opioid related harm, then the medication is weaned and ceased.

The patient and the prescribing practitioner enter into an ‘Opioid contract’ keeping the above principles in mind. If the opioid contract is not followed, then the prescribing practitioner has the authority to cease prescription of opioids with the intention of keeping the patient safe from opioid related harm.

How do Opioid Pain Medications Alleviate Chronic Pain?

Opioid pain medications alleviate chronic pain by interacting with specific receptors in the brain, spinal cord, and other parts of the nervous system to alter the way the body perceives pain.

For instance, they reduce pain perception and lower the intensity of pain by acting directly on the central nervous system. For people with chronic pain, such as those with cancer or long-term conditions like osteoarthritis, opioids can make the pain more tolerable by dulling the brain’s awareness of pain stimuli.

While opioids don’t cure the underlying condition causing chronic pain, they may improve the quality of life by allowing patients to perform daily activities and function better. This is especially true in cases of cancer pain when other treatments are insufficient.

Patients with chronic conditions often experience breakthrough pain, which is a sudden, intense flare-up of pain despite being on a regular pain medication regimen. Short-acting opioids can quickly relieve this kind of pain, helping to prevent severe discomfort. However, the risk of dependence with immediate release preparations of opioids is high and these are only used sparingly and rarely.

In chronic pain management, opioids are often used in combination with other treatments to minimise the risks of dependence and improve overall effectiveness. For example:

• Non-Opioid Pain Relievers. Opioids can be combined with acetaminophen, NSAIDs, or antidepressants to reduce the opioid dose needed while still providing pain relief.
• Physical Therapy. Helps improve mobility and reduce reliance on opioids.
• Cognitive-Behavioral Therapy (CBT). Can help manage the emotional aspects of chronic pain.
• Nerve Blocks or Injections. In some cases, nerve blocks or injections may be used alongside opioids to treat chronic pain conditions.

Why Would You Take Opioid Pain Medications for Chronic Pain?

Taking opioid pain medications for chronic pain can be appropriate in certain situations where the benefits outweigh the risks, particularly when other pain management strategies have not provided sufficient relief.

Severe Pain That Other Treatments Can’t Control

When non-opioid medications like paracetamol, NSAIDs, or other pain relief therapies are not effective, opioids may be considered. Conditions such as cancer pain, post-surgical pain, or severe osteoarthritis often cause pain levels that over-the-counter or non-opioid prescription medications can’t adequately manage.

Non-drug therapies, such as physical therapy, acupuncture, or psychological interventions, may not be enough on their own to manage severe, persistent pain, making opioids a necessary part of the treatment plan.

Improvement of Quality of Life

Chronic pain can severely limit a person’s ability to perform everyday activities, such as walking, working, or even sleeping. For some people, opioids offer enough pain relief to restore a basic level of functioning, enabling them to participate in daily activities and improve their overall quality of life.

Managing Specific Types of Chronic Pain

Opioids are a critical part of pain management for people with cancer, especially when the pain is related to tumours, bone metastases, or cancer treatments like chemotherapy or radiation. For these patients, opioids can provide long-term relief and help control both constant pain and “breakthrough pain.”

Some people develop long-lasting pain after surgery, such as post-mastectomy pain or phantom limb pain after amputation. Opioids can be an effective option when other treatments don’t provide sufficient relief.

Conditions like severe trauma, spinal cord injuries, or multiple fractures can cause long-term pain, and opioids may be used to help manage this pain over time.

Intractable Pain Conditions

For some chronic pain conditions, like severe neuropathic pain (nerve pain) or complex regional pain syndrome (CRPS), opioids may be considered if other medications like anticonvulsants or antidepressants are ineffective. In general, in chronic non-cancer pain, if opioids are used at all, atypical opioids are preferred over typical opioids to minimise the risk of long term harm.

Risks of Opioid Pain Medications

Opioid pain medications are effective at managing pain, particularly for moderate to severe pain, but they come with significant risks. These risks become more pronounced with long-term use and higher doses.

Addiction and Dependence

Opioids have a high potential for addiction. Addiction occurs when someone compulsively seeks and uses the drug despite harmful consequences, such as damage to health, relationships, or daily functioning. Opioids trigger the release of dopamine, leading to feelings of euphoria, which can drive misuse.

Over time, the body becomes dependent on opioids, meaning withdrawal symptoms occur when the medication is reduced or stopped. Dependence is a physical adaptation and can happen even when opioids are taken as prescribed.

With prolonged use, people may develop tolerance, meaning they need higher doses to achieve the same pain-relieving effect. This can lead to escalating doses and increase the risk of addiction and overdose. People who develop opioid addiction may withdraw from social activities, relationships, and responsibilities, leading to isolation.

Overdose Risk and Death

Opioids depress the central nervous system, including the respiratory centres in the brain, which can slow or stop breathing, especially at high doses. This can lead to overdose and be fatal.

Taking opioids with other central nervous system depressants, such as alcohol, benzodiazepines (like Valium or Xanax), or sleep medications, increases the risk of overdose.

Opioid-Induced Hyperalgesia

In some cases, long-term opioid use can cause opioid-induced hyperalgesia, where patients become more sensitive to pain. This paradoxical effect can make chronic pain worse, even as the patient continues to use opioids to alleviate it.

Cognitive and Psychological Effects

Opioids can cause sedation, impairing the ability to think clearly, concentrate, or make decisions. This increases the risk of accidents, especially when driving or operating heavy machinery.

Opioids can cause mood swings, depression, or anxiety, especially with long-term use. This is partly because of their effects on brain chemistry and partly due to the emotional toll of managing chronic pain.

Constipation and Gastrointestinal Issues

Opioids slow down bowel movements, leading to constipation, which is a common and often severe side effect. Chronic opioid use can also lead to other gastrointestinal issues, such as bloating, nausea, and abdominal pain. Opioids can lead to slowing down of stomach emptying causing a condition called gastroparesis which is difficult to treat and manage.

Long-term constipation can cause discomfort and reduce appetite, leading to poor nutrition and overall health deterioration.

Hormonal Imbalance and Sexual Dysfunction

Long-term opioid use can disrupt the production of hormones, such as testosterone and cortisol, leading to conditions like hypogonadism (low testosterone) in men and menstrual irregularities in women. Opioid use can lower sex drive and contribute to sexual dysfunction, including erectile dysfunction in men and decreased fertility in women.

Immunosuppression

Opioids in the long term can suppress the immune system, making it more likely to develop recurrent infections in different parts of the body.

Opioid induced headaches and sleep disturbances

Opioids can cause opioid induced headaches which are difficult to treat. They also lead to disturbance in sleep cycle and circadin rhythm resulting in insomnia and reducing the ability to tolerate pain during the day.

Risk of Misuse and Diversion

Some individuals may misuse opioids by taking them in ways not prescribed, such as taking higher doses or combining them with other drugs to enhance their effects. This increases the risk of addiction and overdose.

Prescription opioids are sometimes sold or given to others who do not have a prescription, contributing to the opioid crisis and the rise of opioid misuse in the general population. Illicit acquisition, possession, or distribution of prescription opioids can result in legal problems, including arrest and incarceration.

Respiratory and Cardiovascular Effects

Opioids can exacerbate sleep apnea by reducing muscle tone in the airways and suppressing the respiratory system.

In some cases, long-term opioid use may be linked to an increased risk of cardiovascular problems, such as heart attacks, due to the effects on blood pressure and oxygen levels.

Increased Risk of Falls and Injuries

Drowsiness and sedation from opioids can impair balance, coordination, and motor skills, increasing the risk of falls and accidents, particularly in older adults. Accordingly, opioid-induced dizziness or weakness may lead to falls, resulting in fractures or other serious injuries, especially in those with weakened bones.

Impact on Mental Health

Long-term opioid use is associated with a higher risk of mental health disorders such as depression and anxiety. This may result from the interaction of opioids with brain chemistry, the emotional toll of dependence, or the chronic pain itself.

Chronic pain combined with opioid dependence and other health or personal issues can increase the risk of suicidal thoughts or actions.

Social Stigma

People using opioids, especially for long-term pain management, may face social stigma or judgement, both from the public and sometimes from healthcare providers. This can affect their willingness to seek help or treatment.

Development of Tolerance to Opioid Medications

As tolerance develops, the pain-relieving effects of opioids diminish, requiring higher doses to achieve the same effect. This can lead to a cycle of escalating doses, increasing the risk of addiction, side effects, and overdose.

Risk of Withdrawal Symptoms

If a person stops taking opioids suddenly or reduces the dose too quickly, they may experience withdrawal symptoms such as sweating, chills, nausea, muscle aches, anxiety, and irritability. This can make it difficult to discontinue opioid use even when the pain has improved. Some people experience prolonged withdrawal symptoms that can last for weeks or months after stopping opioids, including insomnia, depression, and anxiety.

Given these risks, opioids should be prescribed with caution, typically for short-term or severe acute pain when other treatments are not effective. For chronic pain, opioids are often considered a last resort and are used under close medical supervision with regular monitoring to minimise these risks. In chronic pain, atypical opioids are considered as the main option with avoidance of typical opioids in most circumstances. Please note that Dr Mittal does not promote the use of opioids in chronic non-cancer pain unless there are exceptional circumstances and certain criteria have been met. The clinic strongly adheres to the position statement of the Faculty of Pain Medicine (PS01(PM) 2021).