The discomfort of pain may often restrict one to carry out a normal daily routine. The following article aims to list down all the non-narcotic methods of pain management like non-opioid analgesics, patient education, surgical interventions, complementary therapies and others.

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Function of pain

Pain is “an unpleasant sensory and emotional experience associated with actual or potential tissue damage” when there is no physical derangement. The function of pain is to protect the body by making the organism aware of damaging events and to promote healing by causing sensitivity to movement or other stimuli that may delay recovery.

However, neuropathic pain is caused by a lesion or disease of the somatosensory parts of the nervous system, and with some other chronic pain conditions, such as fibromyalgia and migraine.

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Acute and chronic pain

Acute pain is often the reason for visiting an emergency department, and surgical procedures are often associated with acute postoperative pain.

Chronic pain on the other hand causes prolonged discomfort and suffering. Chronic pain has long been treated with opioid analgesics. Long-term opioid administration has minimal effects on chronic pain and can cause tolerance, drowsiness, and dependence, as well as impaired memory, concentration, and judgment. For these reasons, the International Association for the Study of Pain recommends caution in prescribing opioids for chronic pain, and there has been an increased emphasis on the use of nonopioid pain management.

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Other methods of pain management

Nonopioid analgesics- Several analgesic agents, developed primarily for conditions other than pain and with various biologic sites of action, are available. These include nonsteroidal anti-inflammatory drugs (NSAIDs), antidepressant agents, and antiepileptic drugs.

NSAIDs

Acetaminophen (also known as paracetamol) has well-known analgesic and antipyretic effects. It is widely used as an over-the-counter and prescription analgesic, but its mechanisms of action are not known. There is a small risk of severe skin reactions and the risk of liver damage and hepatotoxicity if this agent is used in large doses.

Although acetaminophen is still considered the safest analgesic, no high-quality studies have assessed chronic adverse effects, and the Food and Drug Administration (FDA) is monitoring the safety of its use during pregnancy.

Aspirin (acetylsalicylic acid) and other NSAIDs, unlike acetaminophen, have anti-inflammatory properties and inhibit platelet aggregation. The side effects of NSAIDs include nausea, gastrointestinal bleeding, and hypersensitivity reactions. With an exception of aspirin, they are associated with a risk of heart attack or stroke.

Antidepressant agents

Several drugs initially developed for the treatment of depression have been used for chronic pain. Tricyclic antidepressants and serotonin-norepinephrine (noradrenaline) reuptake inhibitors (SNRIs) reduce the intensity of pain in patients who have depression and in those who do not.

However, antidepressants may be more effective in patients with both pain and depressive symptoms than in those with pain alone. The reason for the analgesic effect is not known but may be related in part to presynaptic inhibition of the reuptake of serotonin and norepinephrine in pain inhibitory pathways, as well as peripheral mechanisms involving β2-adrenergic receptors and the opioid system.

Tricyclic antidepressants and SNRIs have been used as first-line treatments for neuropathic pain. A study aiming to study the effect of drugs to achieve at least a 50% reduction in neuropathic pain in patients was 3.6 for tricyclic antidepressants and 6.4 for SNRIs. Antidepressants have also been recommended for prophylactic treatment of migraine and tension-type headaches.

There is some evidence of an analgesic effect of these drugs on pain from fibromyalgia. Amitriptyline is the tricyclic antidepressant with the best-documented analgesic effects, but desipramine, nortriptyline, and imipramine are likely to have less pronounced anticholinergic and sedative side effects and are associated with a lower risk of falls.

Antiepileptic medications

Several drugs used for the treatment of epilepsy have apparent analgesic properties through their putative effects of lowering neurotransmitter release or reducing neuronal firing. Gabapentin and pregabalin cause reduced calcium-dependent release of excitatory neurotransmitters, thereby decreasing neuronal excitability.

Gabapentin and pregabalin are recommended in guidelines for the treatment of neuropathic pain, and pregabalin has also been shown to be effective in trials for pain from fibromyalgia, with modest adverse events. Perioperative use of pregabalin has an opioid-sparing effect on acute postoperative pain but an increased risk of serious adverse events and is therefore not recommended as a routine postoperative treatment for pain.

Side effects such as sedation and dizziness are common with both gabapentin and pregabalin, and there is increasing evidence of misuse and abuse of these drugs. Pregabalin is approved by the FDA only for neuropathic pain and pain from fibromyalgia.

Oxcarbazepine, carbamazepine, lamotrigine, and lacosamide reduce neuronal excitability in the central and peripheral nervous systems. Oxcarbazepine and carbamazepine are first-line treatments for trigeminal neuralgia, and the rate of success with these agents in treating this disorder has been considered to be good.

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Patient education and physiological treatment

The American Pain Society recommends involving the patient in the pain management plan and choosing a treatment that combines pharmacologic and nonpharmacologic methods for managing acute and chronic pain.

Only in refractory cases are pharmacologic, interventional, and surgical treatments considered appropriate. Psychological treatments include cognitive behavioural therapy, hypnosis, mindfulness training, biofeedback, and stress management. Cognitive behavioural therapy involves practical techniques to change physical activity, reduce distress and catastrophising, and improve functioning and social engagement. These techniques include coping strategies, exposure to feared activities, activities that divert attention from pain, and relaxation training.

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Local treatment of pain

An advantage of topical treatment of pain is the absence of effects on the central nervous system and other systemic side effects. Among the most commonly used agents in this class is the lidocaine patch, at a dose of 1.8% or 5%, which is approved by the FDA for postherpetic neuralgia and is recommended for peripheral neuropathic pain.

The patches are applied over the sites of pain for up to 12 consecutive hours per day. They have few side effects but may cause skin irritation. Too few trials have been conducted to provide a dependable estimate of effect sizes. Capsaicin, which is the active pungent ingredient in chilli peppers, activates the transient receptor potential vanilloid channel of small peripheral sensory nerves.

The effect of repeated applications or of a single high-dose application is through desensitisation and a temporary reduction in the number of pain fibres in the skin. The capsaicin 8% patch is a second-line treatment for neuralgias. Local side effects include skin reactions and discomfort on initial application.

To avoid contact with mucous membranes, the capsaicin 8% patch is applied by a health care professional. Up to four patches are applied once for 30 or 60 minutes, and the treatment can be repeated every 3 months. Botulinum toxin type A given subcutaneously in the region of pain is a third-line treatment for peripheral neuropathic pain.

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Interventional pain management

Surgery is indicated for the treatment of pain if the underlying cause can be addressed safely and with a calculated clinical benefit. Examples that fulfil these conditions include the removal of a tumour or a herniated disk adjacent to neural tissue. Devices designed to modulate abnormal activity in the nervous system by stimulating neuronal pathways are used for symptomatic pain treatment.

Interventional treatments are available for pain conditions such as microvascular decompression or percutaneous radiofrequency rhizotomy for trigeminal neuralgia and occipital-nerve stimulation for cluster headache. Epidural analgesia or intrathecal treatment with ziconotide (a selective N-type voltage-gated calcium channel blocker), clonidine (a central α2-adrenergic receptor agonist), bupivacaine, or a combination of these agents may be used for uncontrolled pain associated with cancer.

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Complementary therapy

Many patients with chronic pain use complementary therapies, which include:

• Meditation
• Yoga
• Acupuncture
• Music therapy
• Heat therapy
• Massage
• Chiropractic therapy
• Guided imagery
• Biofeedback

Complementary therapies such as acupuncture and massage are recommended by the American College of Physicians for chronic low back pain. These therapies may support active self-care, and meditation and yoga are recommended to improve psychological well-being.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.