Arthrexin

Arthrexin - Precautions | Dosage | Side Effects

This article was medically reviewed by M.Pharm, Marko Tanaskovic on Thu, 16 Apr 2020. To read more about an author, click here.

Arthrexin is a medicine containing active substance called indomethacin. It belongs to a non-steroidal anti-inflammatory drugs (NSAIDs). It works by inhibiting an enzyme called cyclooxygenase, thereby reducing the production of inflammatory mediators, such as prostaglandins.

It has analgesic (relieves pain) and anti-inflammatory (reduces inflammatory processes) effects.

Indications

The US Food and Drug Administration states that this drug can be used to treat rheumatoid arthritis, ankylosing spondylitis, osteoarthritis, gout-induced arthritis, and acute shoulder pain (bursitis or tendinitis).

In all of the above conditions, it is recommended that the lowest effective dose be administered to reduce the risk of side effects of this drug.

Pharmacokinetics

An article published in the reputable scientific journal Clinical Pharmacokinetics states that Arthrexin is rapidly and extensively absorbed after oral administration, with maximum blood concentrations reached within 1-2 hours. Taking this medicine with food decreases and delays the maximum concentration of the drug in the blood, but has no effect on the amount of the drug that is absorbed into the systemic circulation.

About 90% of the drug binds to plasma proteins, while about 60% of the drug is excreted via its glucuronide form in the urine, and 40% of the drug is excreted via feces.

Contraindications

Arthrexin (indomethacin) is contraindicated in patients allergic to indomethacin and any other NSAID, such as: ibuprofen, diclofenac, naproxen and others. People allergic to acetylsalicylic acid known as Aspirin also must not take Arthrexin.

If you are experiencing symptoms of an allergy, such as urticaria, skin rash, swelling of the face, swelling of the tongue and throat, or angioedema, you should contact your doctor immediately. Anaphylactic shock has been reported in patients using NSAIDs.

Patients who need to undergo coronary artery bypass surgery, must not take Arthrexin.

Precautions

NSAIDs belong to a group of drugs that increase the risk of adverse cardiovascular thrombotic events, such as stroke and heart attack. The incidence of these side effects for indomethacin is unknown, but Arthrexin is not recommended for patients who have had a stroke or a heart attack, or are at increased risk for these or other thromboembolic disorders.

Cases of portal vein acute thrombosis, as well as acute thrombocytopenia (decreased platelet levels) have been reported in patients taking Arthrexin (indomethacin).

If you are experiencing symptoms of a heart attack (pain or discomfort in the chest, shoulders, or arms, or difficulty breathing) or stroke (sudden numbness of the arms, legs or face, difficulty walking, loss of coordination, severe headache, or difficulty speaking), you should contact your doctor immediately.

Arthrexin should also not be used in patients who have hypertension (high blood pressure) as it has been shown that it might worsen condition in these patients.

Arthrexin (indomethacin), like all other NSAIDs, can cause gastrointestinal side effects such as ulceration and bleeding in the gastrointestinal tract. People who have a positive history of ulcer or bleeding in the gastrointestinal tract are at 10-fold higher risk to develop these side effects compared to people who do not have a positive history. If you are experiencing stomach pain or a black stool, you should contact your doctor immediately.

Arthrexin (indomethacin) is not recommended in people with kidney damage, as studies have shown that this medicine can cause kidney damage, especially after long-term use.

It should be kept in mind that Arthrexin can cause an increase in blood potassium levels (hyperkalemia) and therefore should not be given concomitantly with medicines that also increase blood potassium levels (such as potassium sparing diuretics). If you are experiencing irregular heartbeat, which is one of the signs of hyperkalemia, contact your doctor immediately.

Literature states that Arthrexin (indomethacin) can worsen the condition in patients with depression, Parkinson's disease or epilepsy, and therefore should be avoided in these patients.

Dosage

Arthrexin should not be used in patients under 14 years of age.

The recommended starting dose in treating rheumatoid arthritis is 25 mg once a day. The dose should be gradually increased (increase dose for 25 or 50 mg, once a week) until the lowest effective dose is reached. The maximum daily dose is 150 mg daily, divided into multiple doses.

The recommended dose for shoulder pain therapy is 25 mg 3-6 times daily (every 8, 6 or 4 hours). Therapy should not last longer than two weeks.

The recommended dose for the treatment of gout-induced arthritis is 50 mg once a day.

Taking doses greater than 150 mg does not increase the efficacy of the drug.

Keep in mind that taking higher doses of this drug and taking it longer than recommended, significantly increases the risk of side effects, so it is imperative that you carefully follow instructions given by your doctor.

Use of Arthrexin During Pregnancy and Breastfeeding

Arthrexin should not be used during pregnancy, especially during the last trimester, as studies have shown that it causes premature closure of ductus arteriosus. Animal studies at doses less than those recommended in humans, have shown that Artrhexin (indomethacin) leads to an increased incidence of malformations and had a negative effect on fetal ossification (bone formation disorder).

Arthrexin should therefore not be used during pregnancy!

Arthrexin is excreted in breast milk and can cause side effects in infants. For this reason, it is recommended to avoid breastfeeding while taking this medicine.

Interactions

Arthrexin may interact with a number of drugs, with interactions with the drugs listed below being major:

  • Acalabrutinib - a drug used in the treatment of lymphocytic leukemia. Concomitant use with this drug increases the risk of bleeding
  • Betrixaban, anisindione, dicumarol, warfarin, ardeparin, dalteparin, enoxaparin, fndaparinux, tinzaparin and fraxiparin - anticoagulants (prevent thrombus formation by reducing coagulation). Concomitant use with these drugs increases the risk of serious bleeding that can be life-threatening
  • Adefovir - a medicine used to treat hepatitis B. Concomitant use with this medicine increases the risk of renal toxicity (kidney damage)
  • Cidofovir - a medicine used to treat viral eye infection (cytomegalovirus retinitis). Concomitant use increases the risk of kidney damage
  • Everolimus - an immunosuppressant used to prevent organ rejection in patients who have undergone transplantation. Everolimus, like Arthrexin, can cause kidney damage, so concomitant use is not recommended
  • Angiotensin II antagonists, such as: losartan and valsartan. These medicines are used in the treatment of hypertension, and it has been shown that Arthrexin can diminish the antihypertensive effect of these medicines, and increase blood pressure in people taking these medicines.

This is not a complete list and it does not show all the drugs that Arthrexin can interact with. That is why it is very important that you inform your doctor about all the medicines you are taking.

Adverse Effects

Arthrexin can cause the following side effects:

  • Flatulence
  • Ulceration in the gastrointestinal tract
  • Gastrointestinal bleeding
  • Insomnia
  • Drowsiness
  • Anxiety
  • Involuntary muscle movements
  • Rapid heartbeat
  • High blood pressure
  • Heart attack
  • Stroke
  • Double vision
  • Blurred vision
  • Hearing disorders including deafness
  • Weight gain
  • Interstitial nephritis (kidney damage)
  • Anemia
  • Fluid retention
  • Allergic reactions

If you are experiencing any side effects, inform your doctor immediately.

References

  1. FDA
  2. Helleberg L. Clinical Pharmacokinetics of indomethacin. Clin Pharmacokinet. 1981. 6(4): 245-58.
  3. Mantarro S, Tuccori M, Pasqualetti G, et all. Acute portal vein thrombosis precipated by indomethacin in a HCV-positive elderly patient. BMC Geriatr. 2012. 12:69.
  4. Camba L, Joyner MV. Acute thrombocytopenia following ingestion of indomethacin. Acta Haematol. 1984. 71(5): 350-2.
  5. CDC

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If you have any concerns or questions about your health, you should always consult with a physician or other health-care professional.