ASK DIS: Pharmacological Management of Low Back Pain

Classification of Low Back Pain

Acute low back pain: Low back pain present for fewer than 4 weeks, sometimes grouped with subacute low back pain as symptoms present for fewer than 3 months
Chronic low back pain: Low back pain present for more than 3 months.

Treatment for Low Back Pain

PARACETAMOL:

Acetaminophen is a slightly weaker analgesic than but is a reasonable first-line option for treatment of acute or chronic low back pain because of a more favorable safety profile and low cost.
According to NICE guideline on Low Back Pain 2009, they advise to take regular paracetamol as the first medication option.
When paracetamol alone provides insufficient pain relief, offer, non-steroidal anti-inflammatory drugs (NSAIDs) and/or weak opioids.
According to Guideline for the Low Back Pain Evidence-Informed Primary Care Management of, first choice is acetaminophen; second choice NSAIDs.

NSAIDS:

Nonselective NSAIDs are more effective for pain relief than acetaminophen, but they are associated with well-known gastrointestinal and renovascular risks.
A proton pump inhibitor (PPI) should be considered for patients over 45 years of age when offering treatment with an oral NSAID/COX-2 inhibitor.
There is no clear difference between different types of NSAIDs.

OPIOIDS:

Opioid analgesics or tramadol are an option when used judiciously in patients with acute or chronic low back pain who have severe, disabling pain that is not controlled (or is unlikely to be controlled) with acetaminophen and NSAIDs.
However clinical experience suggests the use of opioids may be necessary to relieve severe musculoskeletal pain. If used, opioids are preferable for only short term intervention.
Long-term use of weak opioids, like codeine, should only follow an unsuccessful trial of non-opioid analgesics.
In severe chronic pain, opioids are worth careful consideration.
Long acting opioids can establish a steady state blood and tissue level that may minimize the patient’s experience of increased pain from medication withdrawal experienced with short acting opioids.

MUSCLE RELAXANTS:

Some muscle relaxants (e.g. cyclobenzaprine) may be appropriate in selected patients for symptomatic relief of pain and muscle spasm.
Only consider adding a short course of muscle relaxant (benzodiazepines, cyclobenzaprine, or antispasticity drugs) on its own, or added to NSAIDs, if acetaminophen or NSAIDs have failed to reduce pain.
Although the antispasticity drug tizanidine has been well studied for low back pain, there is little evidence for the efficacy of baclofen or dantrolene, the other FDA-approved drugs for the treatment of spasticity.
Treatment with baclofen was compared to placebo in a double blind, randomized study of 200 patients with acute low back pain. Patients with initially severe discomfort were found to benefit from baclofen, 30mg to 80mg daily
According to a Journal published in 2011, eperisone hydrochloride was effective and well tolerated for the treatment of patients acute musculoskeletal spasm associated with low back pain. The normal dosing that is usually given is 50mg every 8 hours.
Other medications in the skeletal muscle relaxant class are an option for short-term relief of acute low back pain, but all are associated with central nervous system adverse effects (primarily sedation).

TRICYCLIC ANTIDEPRESSANTS:

Tricyclic antidepressants have a small to moderate effect for chronic low back pain at much lower doses than might be used for depression.
Tricyclic antidepressants are an option for pain relief in patients with chronic low back pain and no contraindications to this class of medications.
According to NICE on Low Back Pain (2009), consider offering tricyclic antidepressants if other medications provide insufficient pain relief.
Start at a low dosage and increase up to the maximum antidepressant dosage until therapeutic effect is achieved or unacceptable side effects prevent further increase.
Do not offer selective serotonin reuptake inhibitors (SSRIs) for treating pain.

References:

http://www.nice.org.uk/guidance/cg88/evidence/cg88-low-back-pain-full-guideline3