Cyclobenzaprine and gabapentin
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Cyclobenzaprine and Gabapentin: Uses, Efficacy, and Safety Concerns
Introduction to Cyclobenzaprine and Gabapentin
Cyclobenzaprine and gabapentin are commonly used medications for managing pain and muscle spasms. Cyclobenzaprine is a muscle relaxant, while gabapentin is an anticonvulsant that is also effective in treating neuropathic pain. Both drugs can be administered orally or topically, and their use in compounded topical pain medications is increasingly popular due to the potential for reduced systemic side effects.
Efficacy of Topical Administration
Pain Relief and Absorption
Topical administration of cyclobenzaprine and gabapentin has been shown to provide significant pain relief. In a case study, a compounded topical cream containing cyclobenzaprine 2% and gabapentin 6% among other ingredients was effective in alleviating pain for a patient with degenerative disc disease and cervical radiculopathy1. However, the efficiency of transdermal delivery varies between these drugs. Gabapentin concentrations in urine were significantly lower in patients using it topically compared to those using it orally, indicating lower percutaneous absorption2. Conversely, cyclobenzaprine was more readily detectable in the urine of topical users, suggesting better absorption through the skin2.
Safety Concerns and Adverse Reactions
Allergic Reactions
Despite the benefits, topical use of these medications can lead to adverse reactions. A notable case involved a patient developing allergic contact dermatitis to cyclobenzaprine in a compounded topical cream. Patch testing confirmed hypersensitivity to cyclobenzaprine, which was the primary allergen causing the rash1. This highlights the importance of monitoring for allergic reactions when using topical formulations.
Systemic Toxicities
Systemic toxicities are another concern, especially with compounded topical pain products (CTPPs). A study reported multiple cases of systemic toxicities, including dizziness, nausea, and even fatal outcomes, associated with the use of CTPPs containing cyclobenzaprine and gabapentin among other drugs3. One patient experienced fatal systemic toxicity attributed to the combined effects of ketamine and cyclobenzaprine3. These findings underscore the need for cautious use and close monitoring of patients using these medications topically.
Conclusion
Cyclobenzaprine and gabapentin are effective in managing pain when used topically, but their safety profiles necessitate careful consideration. While cyclobenzaprine shows better percutaneous absorption compared to gabapentin, both drugs can cause significant adverse reactions, including allergic contact dermatitis and systemic toxicities. Healthcare providers should be vigilant in monitoring patients for these potential side effects to ensure safe and effective use of these medications.
Sources and full results
Most relevant research papers on this topic
Novel use of patch testing in the first report of allergic contact dermatitis to cyclobenzaprine.
Cyclobenzaprine is the cause of allergic contact dermatitis in a patient with cervical dysesthesia, suggesting it may be a potential allergen in pain medications.
Case ReportUrinary Concentrations of Topically Administered Pain Medications.
Topical pain medications like gabapentin and ketamine are more readily detectable in urine than oral medications, but cyclobenzaprine and amitriptyline levels are less likely to be detectable.
Observational StudyMultiple drugs
Multiple drugs can cause systemic toxicities, including seizures, cardiac arrest, and lower extremity oedema and paraesthesia, when applied to the skin for pain treatment.
Gabapentin: An Alternative to the Cyclooxygenase-2 Inhibitors for Perioperative Pain Management
Gabapentin (1.2 g/d PO) is an acceptable alternative to rofecoxib (50 mg/d PO) for short-term use as an adjuvant to opioid analgesics in patients undergoing lower abdominal surgery.
RCT
Highly CitedGabapentin misuse, abuse and diversion: a systematic review.
Gabapentin misuse is prevalent globally, with substance abuse populations at a higher risk for misuse/abuse, primarily for recreational purposes and self-medication.
Systematic Review
Rigorous JournalHighly CitedCyclobenzaprine hydrochloride effect on skeletal muscle spasm in the lumbar region and neck: two double-blind controlled clinical and laboratory studies.
Cyclobenzaprine hydrochloride effectively treats muscle spasms and pain in the neck and low back, with a preference for its effectiveness in improving electromyographic findings.
RCTHighly CitedGabapentin as an antiepileptic drug in man.
Gabapentin shows a dose-related antiepileptic effect in patients with severe epilepsy, is well-tolerated, and shows no significant drug interactions.
Highly CitedThe Skeletal Muscle Relaxer Cyclobenzaprine Is a Potent Non-Competitive Antagonist of Histamine H1 Receptors
Cyclobenzaprine, a muscle relaxant, facilitates sedation by noncompetitively antagonizing central histamine H1 receptors, potentially explaining its high sedative effect in patients.
In Vitro StudyEfficacy of a low-dose regimen of cyclobenzaprine hydrochloride in acute skeletal muscle spasm: results of two placebo-controlled trials.
A low-dose regimen of cyclobenzaprine (5 or 10 mg TID) is effective in improving muscle spasm, reducing pain, and increasing range of motion in acute musculoskeletal conditions, with less sedation than the usual 10 mg TID dose.
RCT
Large Human TrialHighly Cited