What Is Diclofenac and What Is It For?

Diclofenac is a medication used to treat general pain and inflammation. Although it's usually well tolerated, it can cause certain side effects that are worth knowing about.

Written and verified by el biólogo Samuel Antonio Sánchez Amador.

Last update: 08 September, 2021

Diclofenac is an aryl-acetic derivative non-steroidal anti-inflammatory drug (NSAID) used to treat inflammatory diseases and pain. The success is achieved through the inhibition of the enzyme cyclooxygenase, key in the synthesis of prostaglandins. It can be prescribed orally, as a rectal suppository, as an injection, or as a topical gel.

It should be noted that diclofenac is the active ingredient, but the drugs that contain it can have several different names, depending on the manufacturer. Some of them are the following: Artrotec ®, Di Retard ®, Dicloabac ®, Dolo Voltaren ®, Dolotren ®, Luase ®, Normuen ® and Voltaren ®.

This drug was patented in 1965 and started to be used in the United States in 1988. In 2018, diclofenac was the 72nd most-prescribed drug, with more than 11 million prescriptions annually in this country alone.

What is diclofenac used for?

As we’ve said, diclofenac is a non-steroidal anti-inflammatory drug (NSAID). Generally, this group of medications is prescribed to reduce pain, lower fever, and reduce inflammatory responses.

Diclofenac is part of the group of phenylacetic acids and specializes in reducing inflammation. In addition, it has certain analgesic and antipyretic properties shared with other NSAIDs. To perform its functions, this drug inhibits the action of the enzyme cyclooxygenase 1 (COX-1) and cyclooxygenase 2 (COX-2).

These enzyme groups are vital for the formation of prostaglandins, prostacyclins, and thromboxanes. All three compounds carry out inflammatory responses and participate in pain perception (nociception).

The inhibition of COX-2 appears to be quite localized in the target tissue (synovial fluid and joints), as indicated by the Statpearls portal. However, the antagonistic action towards COX in other areas (such as the stomach) could cause the depletion of protective responses and certain side effects, such as gastric irritation.

General uses

Diclofenac can be used on several fronts, as is often the case with many NSAIDs. Anyway, in the following list we mention its most common uses:

• Chronic inflammatory rheumatic diseases: rheumatoid arthritis, ankylopoietic spondyloarthritis, and osteoarthritis, among others
• Extra-articular rheumatism
• Acute attacks of gout
• Menstrual cramps
• Post-traumatic inflammation
• Pain caused by kidney and gallbladder stones
• Pain after surgery, especially if accompanied by inflammatory reactions

Although the uses strictly approved by the Food and Drug Administration (FDA) are quite limited, this drug is also prescribed off-label for many other things. For example, for the management of symptoms such as gallstones, corneal abrasion, fever, gout, migraine, myalgia and to manage pain after an episiotomy.

How is diclofenac administered?

Covering the complete dosage of diclofenac is a very complex task, since, as we’ve already said, it has many different forms of administration. However, we’ll now divide its doses and intakes according to the route of entry of the drug into the body.

Oral pills

We’re going to elaborate more on this variant, as it’s the one that has been prescribed most in the domestic environment. Specifically, we’re going to look at the package insert for Diclofenac CINFA 50 mg ®. Each gastro-resistant tablet of this brand contains 50 milligrams of the active ingredient and its dosage can be summarized in the following points:

• Adults and over 14-year-olds: For cases of mild pain, 100 milligrams a day is recommended, that is, 1 tablet twice a day. The limit of 150 milligrams per day (3 pills in 3 doses) should not be exceeded.
• For menstrual cramps: In this case, a slightly wider spectrum is conceived, from 50 milligrams (1 pill) to 200 milligrams (4 pills). Treatment should begin as soon as the first symptom is observed and you may continue it for a few more days.

Topical administration gel

We’re now going to talk about the Diclofenac Kern Pharma 11.6 mg / g gel® package insert.

• Adults and adolescents over 14 years: Apply 3 or 4 times a day a small film of gel on the swollen and painful area. The amount of drug will depend on the extent of the inflammation.
• Children under 14 years of age: There isn’t enough data to be sure of the efficacy of this drug in young children. Therefore, its use isn’t recommended.

Intravenous administration solution

The leaflet used in this case is DICLOFENACO LLORENS 75 mg SOLUCION INJECTABLE EFG ®. This drug comes in the form of a blister pack that’s injected intramuscularly, as a deep intragluteal injection in the right upper quadrant.

The recommended dose is 1 ampoule (75 milligrams) once a day. However, in the most severe cases, this dosage can be doubled with a second injection. This drug variant shouldn’t be administered for more than 2 days.

Rectal administration suppository

Finally, we’d like to mention the rectal variant based on the DICLOFENACO LLORENS 100 mg SUPPOSITORIES EFG ® leaflet. In this case, the main dose is 1 suppository a day (100 milligrams).

Doses are slightly higher for menstrual cramps, 50 to 200 milligrams a day. The administration is carried out rectally, but if the operation is too difficult and the suppository is very hard, it can be chilled in the refrigerator for a few minutes before application. The patient shouldn’t divide the suppositories into pieces, and certainly shouldn’t take them orally.

Who shouldn’t take diclofenac?

First of all, any patient who has shown hypersensitive reactions to the drug or to any of the excipients shouldn’t take diclofenac in any of its forms. Neither is it intended for those with an allergy to acetylsalicylic acid (aspirin) or other over-the-counter pain relievers.

It’s contraindicated in patients with a clear risk of suffering from cardiovascular diseases, such as cerebrovascular accidents (CVA). For the same reason, it shouldn’t be used to relieve pain after surgery involving the heart or associated structures.

This drug isn’t usually used to manage pain in those with gastric ulcers and other problems in the digestive system. As we’ve said, gastrointestinal symptoms are very common after taking NSAIDs.

What are the possible side effects?

Like any other existing drug, diclofenac can cause certain short-term and long-term side effects. We present them below, based on the symptoms of oral pills.

We’ll start with those common side effects that can affect up to 1 in 10 people:

• Nervous system disorders: headache and dizziness.
• Ear disorders: vertigo.
• Gastrointestinal problems: vomiting, nausea, diarrhea, heartburn, abdominal pain, gases, and lack of appetite.
• Hepatobiliary disorders: increased serum transaminases.
• Skin disorders: skin rashes.

Uncommon side effects (1 in 100 people) usually appear in the form of cardiovascular disorders. Symptoms are palpitations, sudden chest pains, shortness of breath, and swelling in the extremities.

Rare side effects (up to 1 in 1000 people) are also multiple and can be grouped by each area of the body. We can highlight the swelling of the face, difficulty swallowing, hives, fever, drowsiness, and abdominal cramps.

What happens if I miss a dose?

If you miss a dose in oral pill form (assuming that’s your treatment), take it as soon as you remember. However, if it’s already the next day or the time for the second dose, it is best to skip the missed one and continue with the treatment as normal. Never take 2 or more pills to make up for the forgotten ones.

What should I do in case of an overdose?

In case of overdose or accidental ingestion of diclofenac, call your doctor, pharmacist, emergency room, or the Toxicology Information Service promptly. Although previously cited sources emphasize that the toxicity of this drug is low and it doesn’t produce serious clinical signs, these are the most common:

• Nausea and vomiting
• Stomach aches
• Bloody stools
• Vomiting a brown foreign substance
• Drowsiness and slow breathing

A small overdose manifests almost exclusively in the gastrointestinal tract. Seizures, unconsciousness, cardiovascular acidosis, and coma are limited to severe poisonings.

How to store and dispose of this medicine?

If you’re taking diclofenac in its oral variant, the only specification is to keep the pillbox out of the reach of children and in an area that doesn’t exceed 30 degrees Celsius. On the other hand, suppositories should be kept away from heat sources. In its cream form, the maximum duration after opening the container is 12 months.

Whichever variant has been prescribed, don’t throw it away or down the toilet, as this can cause ecosystem damage. Go to an authorized place in your area for the disposal of drugs.

Final notes on diclofenac

Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) that’s used to relieve pain and inflammation in many conditions, from menstrual pain to arthritis. It’s usually well tolerated by the general public, but as we’ve said, its use is avoided in patients with a history of cardiovascular problems and gastrointestinal lesions.

Remember that this medicine relieves pain and inflammation, but it may not solve the cause of the condition on its own. For this reason, it’s common for it to be prescribed with other, much more specific drugs. If you have any questions or queries, don’t hesitate to ask your doctor.