Pain Regimen

https://www.youtube.com/watch?v=06OISvbIhTA&list=PLt6NrpvPjCbKJ7PXXzrmZ2s4U9CUGroPE&index=40

Brief overview of some of the treatment options available to you when a patient is in the hospital and complaining of pain.

Acetaminophen (Tylenol)

Typical dosing: 650mg q4h prn or 1000mg q6hr prn
Max 4g/day in typical patients, max 2g/day in patients with cirrhosis / liver dysfunction
I basically put every patient on prn tylenol on admission
Toxicity isn't usually seen until about 10 grams of tylenol in one day
Also referred to as APAP by some people (N-acetyl-para-aminophenol) - I think sticking with tylenol or acetaminophen is better: APAP: An Error Prone Abbreviation
Consider scheduled doses in patients with uncontrolled pain
Oral or rectal are good routes. IV is good but pharmacy doesn't like you using it too much because it is expensive.

NSAIDs

Make sure patient is not at risk of GI bleed or has an AKI. Not commonly used for inpatients due to these risks.
Ibuprofen (MOTRIN, ADVIL) - 400-600mg PO every 6-8 hrs
I like 400mg because the evidence seems to show it has the same analgesic effect and as you go higher you only increase the risk of side effects.
Naproxen (ALEVE) - can be dosed every 12 hours. Higher risk of GI bleed
Ketorolac (TORADOL) - IV/IM forms available which can be useful especially in patients with nausea. Useful in kidney stones. Highest rate of GI bleed though debatable. 10-15mg is equivalent to 30mg in terms of pain relief. Q6h x48 hours is an appropriate trial in setting of acute pain, after that can transition to celecoxib to reduce the risk of GI bleed or renal issues (200mg BID)
Indomethacin - commonly used in gout, 50mg TID during flare. For general treatment of pain, 20mg TID (I don't see this inpatient much if ever).
Celecoxib (CELEBREX) - newer evidence does not show increased risk of heart attacks / ischemic cardiovascular events. May have lower risk of GI bleed (Chan, et al 2017). Might start seeing this used more going forward.

Lidocaine patch

Good for musculoskeletal pain
Up to 3 patches
Placed and removed every 24 hours
5% form is hard to get outpatient due to insurance coverage issues but there are OTC 2% and 4% forms

Capsaicin cream

Some patients like it, others don't like the burning feeling
Binds to nociceptors in the skin -> initial excitation and enhanced sensitivity -> followed by refractory period with reduced sensitivity and persistent desensitization, possibly due to depletion of substance P
Most effective for osteoarthritis (0.025% cream), neuropathic pain (0.075% cream, not available at our hospital), and cancer-related pain
Double-blind trial showing 80% of patients with osteoarthritis had reduced pain after 2 weeks: https://pubmed.ncbi.nlm.nih.gov/1954640/
Efficacious, but moderate to poor efficacy: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC404499/
High reports of burning/redness, but patients liked it and continued to take it due to decreased neuropathic pain: https://pubmed.ncbi.nlm.nih.gov/9256142/

Diclofenac gel (VOLTAREN gel)

Opioids

Tramadol
- Partial mu and serotonin receptor agonist, "dirty" as it hits a lot of different receptors
- Falling out of favor as patients have very different responses
- Side effect = lowered seizure threshold
- 50mg q4-6hr prn

Oxycodone
- Commonly start with 5mg dose in patients, 2.5mg if elderly
- Onset in 10-30 minutes and lasts 3-6 hours
- Extended release version = OXYCONTIN (lasts for 12 hours)

Hydromorphone (DILAUDID)
- The reasons patients like it is because it has a more rapid onset of analgesia which can produce more euphoria
- Metabolized by LIVER (don't give in liver dysfunction!)

Morphine
- Good for air hunger, decreasing anxiety
- Frequently seen in patients on hospice or comfort care
- Has a liquid version called ROXANOL
- Has an extended version called MS-CONTIN
- Metabolized by KIDNEY (don't give in kidney dysfunction!)

Meperidine (DEMEROL)
- Thought to be good in pancreatitis due to decreased contraction of Sphincter of Oddi
- Useful in patients with rigors

Miscellaneous
- Common outpatient meds - hydrocodone-acetaminophen (NORCO), oxycodone-acetaminophen (PERCOCET, VICODIN). Can continue this when inpatient though typically we do prefer to separate the oxycodone and acetaminophen from each other to optimize dosing
- Make sure everyone on opioids has opioid overdose order set (includes naloxone for reversal if needed)
  Make sure everyone on opioids has a solid bowel regimen (at least miralax and senna)! Constipation common
- USE THE CONVERSION CHART TO SEE DOSING EQUIVALENTS
- When switching from one opioid you may want to consider initially dose reducing about 75% to account for differences in pharmacokinetics

Neuropathic pain treatments

Remember neuropathic pain vs nociceptive pain. Neuropathic pain does not respond well to opioids.
Duloxetine (CYMBALTA)
Venlafaxine (EFFEXOR)
Gabapentin (NEURONTIN)
TCAs are also used for this but very unlikely would be started inpatient, lots of side effects

Methadone

Used in patients who are trying to wean off opioids - long-acting
IV AND PO methadone has QT prolongation which you should be wary about, get pain management involved
If coming in with acute pain, switch from daily dosing to TID as analgesic effect is only about 6-8 hours
Useful in palliative setting
Good for patients with absorption issues (85% bioavailable and predominantly absorbed in the stomach)
Has some benefits for neuropathic pain as well

Ketamine

Buprenorphine

Also gaining popularity
Partial agonist of mu receptor - meaning it acts as an agonist when there's no opioid around. But when there is opioid around it becomes an ANTAGONIST so it prevents people from doing opioids on top of their prescribed pain meds
Has a lower risk of respiratory depression compared to traditional opioids

Miscellaneous

Lidocaine swish & swallow - for mouth pain / ulcers
Lidocaine gel (URO-JET) - for painful Foleys
Warm compress (K-PAD) - for pain related to localized swelling
Muscle relaxants - baclofen, cyclobenzaprine, tizanidine, etc. - they all basically work just by making you sedated and sleepy from what I learned. Doesn't really actually do that much for pain. Baclofen really should only be used for central spastic disease, it's not a great drug, also watch out for baclofen withdrawal in admitted patients (looks kind of like alcohol withdrawal, risk of seizures, etc.)
Long-acting vs short-acting opioids - you shouldn't really ever use long-acting narcotics in the standard patient population. They have high abuse and overdose potential and don't really work well for most acute or chronic pain issues. Their role is really in pain related to cancer or end-of-life related pain. In cancer patients you often will see them combined with short acting in a manner similar to basal-bolus insulin regimens. Per /u/Dominus_Anulorum
Don't forget to make use of consult services
Pain pharmacy consult
Wound care consult

Post-operative pain control

Per u/MMOSurgeon , read more comprehensive post here
For midline, subcostal, Chevron, or Mercedes incisions - thoracic epidural is the gold standard
Standing tylenol is important!
Toradol is an excellent choice, also order it standing
Oral medications ALWAYS WORK BETTER AND LAST LONGER than IV pushes or PCAs
Consider regional blocks
Read the guide from Michigan for discharge to home / how many opioids to send a patient home on