Spinal disorders include over 60 different diseases.  No one therapy is effective for all these disorders.  Specific therapies are listed with the distinct diseases.  Some treatments are beneficial for a number of illnesses, while others are beneficial for only one disorder.  Trying to apply the correct therapy with your specific problem is a discussion between you and your health care provider.  Having some knowledge about the various categories of treatment can facilitate that conversation.  That information can make the use of time with your physician more efficient.

What is Pain?

Pain is defined as an unpleasant sensory and emotional experience that is brought on by damage, or the perception of damage, to the body’s tissues.   This simple statement shortchanges the very complicated interconnections of the nervous system that mediates this sensation.  Damage in the body activates nerves that generate chemicals that transmit pain signals to the spinal cord and then the brain, where the signals are processed into physical sensation of pain.  The transmission chain that propagates these signals is known as the pathways because there are more than one.

How does pain travel?

The nervous system’s communications about pain do not travel only in one direction.  Signals also travel back down the spinal cord, and some of these signals work to reduce pain.  Pain-reducing signals travel along a pain inhibitory pathway, in which the nerve system produces pain-relieving chemicals.  Endorphins, which block transmission of pain signals to the brain, are produced by our bodies to diminish the transmission of pain signals.  Increased activity in the pain inhibitory pathway decreases pain and promotes a feeling of well-being.  For example, individuals who exercise regularly release endorphins that promotes pain relief and a feeling of well-being.  The neurochemicals that stimulate the pain inhibitory pathway include serotonin and norepinephrine.  Exercise increases the levels of these neurochemicals.    Medicines that increase the levels of these neurotransmitters have been shown to be effective in relieving pain.

How many types of pain?

Pain has many characteristics.  These characteristics include onset (when and how it begins), its location (local or radiating), duration (how long it lasts), and its quality (what does it feel like).  Specific characteristics can identify potential sources of that pain.

What is acute pain?

Acute pain acts as a warning signal of an injury.  When an injury occurs, the body releases a specific group of chemicals that signal immediate tissue damage.  These chemicals cause a part of your nervous system to recognize the injury immediately.  The muscles react to this injury by trying to limit damage.  An example is pulling your fingers away from a hot stove.  These acute events do not have a long-term effect on the nervous system.  After the injury heals, the nervous system is no longer stimulated and will return to its painless status.

What is chronic pain?

Chronic pain was once thought to be acute pain that continues the time for normal healing.  It was thought that the same neurochemicals that were released to signal acute pain were released over a longer period of time.  However, investigations have shown that chronic pain has a different set of chemicals that travel along a separate pathway to the brain.  On addition, chronic pain causes changes to structures within the nervous system, and these changes may increase sensitivity to painful stimuli.  IN light of these structural changes in the nervous system, chronic pain may persist even when there is no injury or after an initial injury has healed.  Chronic pain may also develop interactions with nerves in other parts of the brain that control mood and emotions.  Chronic pain may contribute to stress, anxiety, and depression.

What is arthritis pain?

Arthritis can be divided into two basic forms.  In one category are conditions that cause systemic inflammation that is self-perpetuating.  Examples are rheumatoid arthritis, gout, and systemic lupus erythematosus.  Pain associated with inflammatory arthritis is best controlled using drugs that decrease inflammation and thereby decrease inflammatory pain.  Mechanical disorders have no systemic, inflammatory component and can be controlled with therapies that work more on pain than inflammation.

Four major types of drugs ae used to relieve mechanical pain 1) nonsteroidal anti-inflammatory drugs (NSAIDs), pure analgesics, antidepressants, and anti-convulsants.  Acute pain may need only one category of drug to control symptoms.  Chronic pain may need 2 or more categories  of drugs to improve pain.

What are nonsteroidal anti-inflammatory drugs?

NSAIDs are the class of medicine most frequently prescribed for all types of pain, whether acute or chronic, inflammatory or noninflammatory.  NSAIDs reduce swelling, fever, blood clotting in addition to relieving pain.  NSAIDs work by inhibiting an enzyme called cyclooxygenase-2 (COX-2).  COX-2 produces substances called prostaglandins, and at sites of inflammation prostaglandins are associated with heat, swelling, and pain that accompany tissue damage.

In addition to blocking COX-2, most NSAIDs block another enzyme, cyclooxygenase-1 (COX-1).  The prostaglandins made by COX-1 help preserve body functions including kidney function, stomach lining, and normal blood pressure.

Nonselective NSAIDs block both COX 1 and COX2 enzymes.  The nonselective drugs raise the risk of several gastrointestinal problems including heartburn and bleeding ulcers as well as hypertension COX-2 inhibitors may have a decreased potential to cause gastrointestinal distress.

COX-2 inhibitors target COX-2 while leaving COX-1 alone.  By targeting COX-2 and not COX-1, COX-2 inhibitors decrease inflammation while having less toxicity in the gastrointestinal tract.  Cardiovascular effects of all COX inhibitors may be equal.  All NSAIDs are required to have a warning of the potential for increased cardiovascular risk.

NSAIDs belong to different chemical groups.  Individuals may respond to one chemical group and not another.  A NSAID will help about two-thirds of people who take the drug.  That means  some individuals will need to take three or more NSAIDs before finding an effective drug.

NSAID dosing

Each NSAID has its own interval and strength (dose) for how much and how often the drug must be taken.  The NSAIDs that are sold OTC (over the counter) without a prescription are in dose forms below prescription strength.  OTC NSAIDs are ibuprofen, naproxen, and aspirin.    Prescription strength doses of NSAIDs are utilized for chronic inflammatory, painful conditions like ankylosing spondylitis or rheumatoid arthritis.  OTC NSAIDs are used for acute, painful conditions like menstrual cramps or tension headache.

Most NSAIDs are taken orally.  Others come in gels and patches that are applied to painful areas that are close to the body surface.  These topical preparations need to be applied up to 4 times a day to have full potency.  In contrast, oral NSAIDs may be taken once or twice a day for full effect.

NSAID side effects

NSAIDs as a category of drug have characteristic side effects.  It is important to remember that only a small minority of individuals taking the drug experience side effects of the medicine.  Most individuals have no problem taking the medicine.  Some of the potential side effects include

Gastrointestinal – heartburn, esophageal reflux, ulcers, bleeding, diarrhea, constipation, liver irritation

Cardiovascular – high blood pressure, fluid retention, heart attack

Kidney problems – decreased kidney function

Skin – rash

Aspirin sensitivity – “allergic” reaction with difficulty breathing

The risk for side effects are less for OTC NSAIDs if taken at the dose listed on the box.  In equal doses, the Safety profile of OTC NSAIDs is the same as for the prescription forms of the drug

What are pure analgesics?

Pure analgesics reduce pain, but unlike NSAIDs, have no effect on inflammation.  Analgesics are divided into two groups, nonopioid and opioid drugs.

Nonopioid analgesics – Acetaminophen is a popular nonopioid analgesic that works by decreasing prostaglandin production in the brain and spinal cord (but not in other parts of the body).  Acetaminophen may be as effective as NSAIDs in relieving pain without the gastrointestinal side effects.  However, if inflammation is the cause of pain, the efficacy is diminished.  Acetaminophen may be used in combination with other analgesics or NSAIDs.  The use of acetaminophen is associated with the potential of liver toxicity with the risk of liver failure when taken at doses that exceed 4,000 mg a day.  It is important to account for all amounts of acetaminophen when taking this drug.  It is used in many OTC cold medicines, so the maximum safe dose can be exceeded.

Opioid analgesics – Opioids, also known as narcotics, work by mimicking the action of endorphins in the pain inhibitory pathway in out nervous system.  Endorphins, found in the brain, spinal cord, and in peripheral tissues, attach to opioid receptors and block the transmission of pain signals.  The strength of opioids is correlated with how well it binds with endorphin receptors.

Opioid analgesics are available in multiple combinations and formulations.  They include short and long acting forms.  Short-acting are most appropriate for acute pain in a localized area.  Pain associated with an acute injury unassociated with ongoing inflammation.  The medicine is discontinued once the pain symptoms are resolved.

Long-term opioid therapy is prescribed for those individuals whose pain persists despite the use of nondrug therapies, NSAIDs or where NSAIDs are contraindicated.  People taking short-acting opioids may have to transition to long-acting opioids if they are taking a steady dose of short-acting opioids that cannot be decreased without a marked worsening in their physical function.

The recommended opioid dose varies from person to person.  The lowest effective is ideal.  Short-acting opioid, which are cleared rapidly, may need frequent dosing to be effective.  Long-acting opioids, which are designed to be released slowly and stay in the body longer, need to be taken less often in lower doses.

Opioid Toxicities

Opioids, or narcotics, are associated with a wide range of limitations and toxicities.  People taking an opioid may become used to the dose, or tolerant, and need increasing doses to achieve the same pain-relieving effect.  However, more is not always better.  Opioids reach a maximum effect.  Increasing the does is not associated with any greater benefit, only more side effects.

Side effects include constipation, sleepiness, sweating, dizziness, itching, nausea and vomiting.  Older individuals are at greater risk of experiencing toxicities.  With excessive doses, opioids can suppress breathing resulting in death.  This is most likely in people starting opioid therapy and is less of a concern with regular opioid use.

Regular use of opioids results in physical dependence.  Your body becomes reliant on the opioid for normal functioning.  People who have taken opioids for an extended period of time will undergo withdrawl symptoms with stopping opioids abruptly.  Withdrawl symptoms include sweating, abdominal symptoms including cramps and diarrhea.  Tolerance and physical dependence are not the equivalent of addiction.  Addiction is a psychological need for a drug or other substance that causes people to compulsively seek it out.

What are antidepressants?

Anti-depressant drugs help relieve chronic pain in people who are not depressed.  The nervous system has a pathway that helps to suppress pain signals travelling to the brain.  Certain chemicals are the transmitters of signals in this pathway.  The same chemicals are important in other portions of the brain to maintain a positive mood.  Increasing levels of serotonin and norepinephrine with antidepressants increases function in these pathways.

Tricyclic antidepressants such as amitriptyline, increase low levels of norepinephrine and serotonin.  The doses of tricyclics need for effective pain relief are significantly lower that the doses to reverse depression.  Another class of antidepressants named serotonin-norepinephrine reuptake inhibitors (SNRIs) which include duloxetine and milnacipran, have analgesic properties similar to those of tricyclics.  Not all antidepressants have analgesic properties.  For example, selective serotonin reuptake inhibitors (SSRIs) like sertraline and fluoxetine are not effective as pain relievers.

Antidepressant toxicities

Antidepressants have several potential side effects. Tricyclic drugs can include drowsiness, dry mouth, dizziness, blurred vision, and difficulty with urination.  SSRIs and SNRIs can increase the risk for headache, nausea, insomnia and nervousness.  Side effects are more pronounced with tricyclics than with SNRIs and SSRIs.  Also, after prolonged use of the drugs, discontinuation from these drugs needs to be done gradually to limit side effects.

What are anticonvulsants?

Convulsions, or seizures, result from abnormal activation of nerves in the brain.  Calcium channels are structures in cells in the nervous system that transmit electrical signals.  Blocking calcium channels reduces the number of chemical messengers or neurotransmitters released.  Examples of these drugs include gabapentin and pregabalin.  These drugs may be used independently or in combination with other analgesic drugs.  Drugs are given sequentially so that any side effects can be correctly attributed to the most recently added drug.

Anticonvulsant toxicities

Anticonvulsants have several potential side effects.  Toxicities include dizziness, sleepiness, blurred vision, and weight gain associated with swelling in the lower legs.

Individual Pain Therapy

Each person experiences their own pain.  It is unique.  It has characteristics of being acute or chronic, non-inflammatory or inflammatory, generalized or localized.  In addition, individuals have particular sensitivities that can make specific drug toxicities intolerable.  You and your doctor need to take all these factors into consideration to decide on a therapy regimen that is effective and tolerated.  The hope is that as function improves and pain is controlled you will have a better quality of life.