From the Guidelines
Scheduled Inpatient Pain Medications
Non-opioid options that do not cause nephrotoxicity or hepatotoxicity are available for scheduled inpatient pain management. Gabapentin is a suitable option, with a typical starting dose of 100-300mg at bedtime or 100-300mg 3 times daily, titrated to effect, with a maximum dose of 3600mg per day 1. Alternatively, pregabalin may be considered, with a typical starting dose of 50mg 3 times daily or 75mg twice daily, titrated to effect, with a maximum dose of 600mg per day 1. Another option is topical lidocaine, with a typical dosing regimen of a 5% lidocaine patch, with a maximum of 3 patches daily for a maximum of 12-18 hours 1. Some key points to consider when using these medications include:
- Gabapentin and pregabalin require careful titration, especially in patients with impaired renal function 1.
- Topical lidocaine has excellent tolerability and minimal systemic absorption, making it a good option for older patients or those with complex pain conditions 1.
- SSNRIs, such as duloxetine and venlafaxine, may also be considered for certain types of pain, but require careful dosing and monitoring 1.
From the FDA Drug Label
Apparent oral clearance (CL/F) of gabapentin decreased as age increased, from about 225 mL/min in those under 30 years of age to about 125 mL/min in those over 70 years of age. Renal clearance (CLr) and CLr adjusted for body surface area also declined with age; however, the decline in the renal clearance of gabapentin with age can largely be explained by the decline in renal function. Because gabapentin is primarily renally excreted and there are no important racial differences in creatinine clearance, pharmacokinetic differences due to race are not expected. Because gabapentin is not metabolized, no study was performed in patients with hepatic impairment
- Gabapentin is a scheduled inpatient pain medication that does not cause hepatotoxicity since it is not metabolized by the liver.
- However, gabapentin is primarily renally excreted, and its clearance is directly proportional to creatinine clearance, which may indicate a potential risk of nephrotoxicity in patients with renal impairment.
- Given the information provided, gabapentin may not be entirely safe in terms of nephrotoxicity, especially in patients with pre-existing renal impairment.
- Therefore, gabapentin can be considered a scheduled inpatient pain medication that does not cause hepatotoxicity, but its use should be cautious and monitored in patients with renal impairment 2.
From the Research
Scheduled Inpatient Pain Medications
Scheduled inpatient pain medications, excluding opioids, that do not cause nephrotoxicity or hepatotoxicity include:
- Acetaminophen (paracetamol) 3, 4, 5, 6
- Gabapentin 3
- Ibuprofen 5, 6
- JNJ-10450232 (NTM-006), a novel non-opioid with structural similarities to acetaminophen 7
Characteristics of These Medications
- Acetaminophen: does not appear to result in hepatotoxicity at therapeutic doses, although overdose may lead to acute liver failure 4
- Gabapentin: adjusted for renal function to minimize potential nephrotoxicity 3
- Ibuprofen: may have gastrointestinal adverse effects, but does not cause nephrotoxicity or hepatotoxicity at recommended doses 5, 6
- JNJ-10450232 (NTM-006): preclinical models show no evidence of hepatotoxicity associated with overdose, and it was safe and generally well tolerated in a First-in-Human Study 7
Efficacy of These Medications
- Acetaminophen: effective for mild to moderate pain, with a number needed to treat (NNT) for at least 50% pain relief over four to six hours compared with placebo of around 3-4 6
- Gabapentin: effective for moderate to severe pain, although the NNT is not well established 3
- Ibuprofen: effective for mild to moderate pain, with an NNT of around 2-3 5, 6
- JNJ-10450232 (NTM-006): produces relatively long-lasting analgesia after a single dose, with a duration of action sustained up to 24 hours 7