Answer

There is no drug interaction between Skelaxin (metaxalone) and Voltaren (diclofenac). They also don't share many similar side effects and are considered safe to take together.

However, although there is no drug interaction between the two, both are to be used cautiously in those with liver disease. If you have impaired liver function, be sure to speak with your doctor before use of either.

Absent of contraindications, it wouldn't be uncommon for both to be prescribed together. Diclofenac is an anti-inflammatory pain reliever while metaxalone is a muscle relaxant/sedative. They are both used to treat musculoskeletal conditions.

In the next sections, I discuss both drugs in more detail.


About Skelaxin

Skelaxin (metaxalone) is a muscle relaxant and CNS (central nervous system) depressant. It is among the more sedating of oral muscle relaxants.

The exact mechanism of action isn't well known, but the majority of the drugs actions are thought to be due to its CNS depressants effects.

In fact, the prescribing information for Skelaxin states that the muscle relaxant properties come solely from the CNS depressant effects of the drug:

"The mechanism of action of metaxalone in humans has not been established, but may be due to general central nervous system depression. Metaxalone has no direct action on the contractile mechanism of striated muscle, the motor end plate, or the nerve fiber."

Some studies suggest that high doses of Skelaxin may also have serotonergic effects as there have been case reports of serotonin syndrome with the medication.

Skelaxin may be taken with or without food, but food may increase absorption and overall effects of the drug.

The most commonly reported adverse effects include:

  • Drowsiness
  • Dizziness
  • Headache
  • Anxiety and irritability
  • Nausea
  • Vomiting
  • Heartburn

About Voltaren

Voltaren (diclofenac) is a nonsteroidal anti-inflammatory drug (NSAID), and also has pain-relieving and fever-reducing properties.

While in the same class of drugs as Advil (ibuprofen) and Aleve (naproxen), Voltaren may have a slightly lower incidence of GI side effects due to its greater COX-2 selectivity.

Voltaren can be taken with or without food, but food may lessen gastrointestinal side effects.

The most commonly reported adverse effects include:

  • Nausea
  • Ulceration (long term use)
  • GI bleeding (long term use)
  • Dizziness
  • Headache
  • Cardiovascular disease (long term use)

Summary

There is no known drug interaction between Skelaxin (metaxalone) and Voltaren (diclofenac).

References
  • Elsevier ClinicalKey: Diclofenac Monograph (Accessed 1/5/19)
  • Elsevier ClinicalKey: Skelaxin Monograph (Accessed 1/5/19)
  • Serotonin Syndrome Following Metaxalone Overdose and Therapeutic Use of a selective serotonin Reuptake Inhibitor. PubMed (Accessed 1/5/19)
  • Skelaxin Package Insert (Accessed 1/5/19)