Piroxicam: Everything You Need to Know

Piroxicam is a drug used to treat arthritic conditions and other diseases with inflammation and pain. Unfortunately, it reports several side effects that we should bear in mind.

Written and verified by el biólogo Samuel Antonio Sánchez Amador.

Last update: 09 September, 2021

Piroxicam is a non-steroidal anti-inflammatory drug (NSAID) that works by preventing the formation of prostaglandins in the body, by inhibiting the enzyme cyclooxygenase (COX). It is used to relieve the symptoms of certain chronic or acute and painful inflammations, such as rheumatoid arthritis, primary dysmenorrhea, postoperative pain, and osteoarthritis.

Piroxicam is the active substance, but many of the drugs that contain it have different names. Among them we can highlight Feldene ® and Feldene Flas ®. There are also generic drugs with this principle, those that are named directly with the compound and the manufacturing laboratory.

This drug was patented in 1968 by the Pfizer ® Pharmaceutical Corporation and approved for medical use in 1979. It was released as a generic drug in 1992, so it can now be found in cheaper forms available to the general public.

What is piroxicam used for?

As we have said, piroxicam is a non-steroidal anti-inflammatory drug (NSAID). All NSAIDs have certain properties in common and are used to reduce pain, inflammation, and the effects of fever in infectious conditions.

The anti-inflammatory effect of this drug is achieved by inhibiting the synthesis of prostaglandins, a set of lipidic substances derived from essential 20-carbon fatty acids in inflammatory processes. For inflammatory responses to take place, these molecules stimulate vasodilation, tissue permeability, and certain nerve endings.

Mechanism of action

In order to inhibit the formation of prostaglandins, this NSAID acts on several fronts:

• Inhibition of cyclooxygenase-1 (COX-1): the enzyme COX-1 is essential in the synthesis of prostanoids for physiological purposes and regulates functions such as gastrointestinal protection, kidney hemodynamics, vascular homeostasis, and platelet function.
• Inhibition of cyclooxygenase-2 (COX-2): an isoform of COX that regulates the production of prostanoids that participate in inflammation and other non-inflammatory processes. COX-2 is expressed after inflammatory induction, so suppressing it is expected to reduce associated symptoms.
• Impeding the migration of leukocytes to the areas of inflammation.
• Prevention of the formation of thromboxane A2, a platelet aggregating agent.

With all these physiological mechanisms, piroxicam reduces inflammation and pain in certain pathologies. As indicated by the DrugBank portal, its half-life is 30 to 86 hours and the active principle (and by-products) are excreted via the urinary and fecal routes. Notably, it also leaks into breast milk.

Recommended uses

The United States National Library of Medicine lists some of the most common uses for piroxicam. Among them we highlight the following:

• Relief of pain, tenderness, swelling, and stiffness caused by osteoarthritis.
• Relief of the similar symptoms presented in rheumatoid arthritis.
• Reduction of the clinical signs caused by ankylosing spondylitis.
• Relief of symptoms of primary dysmenorrhea.
• As an analgesic after surgery.

How is piroxicam given?

As indicated by the Navarra University Clinic (CUN), in countries like Spain, piroxicam is found in the form of capsules and as an injectable solution. In the following lines, we’ll explore its dosage, according to the route of administration.

Oral pills

In this case, we focus our attention on the Piroxicam Cinfa 20 mg ® package insert, which contains 20 milligrams of active ingredient per capsule. You must bear in mind that not all commercial brands work with the same concentrations.

The general dosage of this drug can be summarized in the following points:

• The tablets can be swallowed directly with the help of a little water or by opening them and dispersing their contents in a glass of liquid.
• The maximum dose is 20 milligrams of piroxicam (1 tablet) as a single dose. This will be reduced as much as possible to achieve the necessary analgesic and anti-inflammatory effects.
• In people over 70, the doses are lower.
• It is not recommended for use in children.

In sources already cited, it is specified that the drug is taken 1 to 2 times a day. This will depend on whether the tablet contains 10 or 20 milligrams of piroxicam and on the severity of the patient’s symptoms. It helps to alleviate the symptoms, but it does not solve the basic condition.

Injectable form

For the injectable form, we’ll look at the package insert for Feldene 20 mg/ml ®, which is introduced into the patient’s body by the intramuscular route. This drug must be administered into a large muscle, so the point of choice for injection is usually the upper outer part of the buttock.

The maximum daily dose is 20 milligrams of piroxicam as a single injection every 24 hours. Once the patient’s situation improves, the transition should be made to taking their oral forms from home, whether they are 10 or 20 milligrams per tablet.

Who shouldn’t take or use this medicine?

First of all, nobody who has shown hypersensitivity reactions to the active substance of the drug or to any of its excipients should take this medication. Among these last compounds, we highlight microcrystalline cellulose (E-460), corn starch, sodium carboxymethyl starch (potato type A), sodium stearyl fumarate, and talc (E-553b).

Apart from allergies, you have to be careful with this drug if you have some acute or chronic diseases:

• Ulcers, bleeding, and perforations in the stomach or intestine. The use of this NSAID is not recommended if these conditions are active, but neither if they have been suffered in the recent past.
• History of gastrointestinal disorders predisposing to bleeding disorders. For example, ulcerative colitis, Crohn’s disease, gastrointestinal neoplasms, and diverticulitis.
• Severe liver or kidney disease.
• Severe heart failure
• Coagulation disorders.

It is also emphasized that piroxicam should not be taken in conjunction with other NSAIDs, including acetylsalicylic acid (aspirin). Finally, you should consider stopping treatment with this drug if you are taking anticoagulants (such as warfarin).

Piroxicam in pregnancy

As indicated in the package insert for this medicine, the use of piroxicam during pregnancy has been associated with congenital fetal anomalies, miscarriages, and loss of amniotic fluid. Therefore, its use is completely contraindicated in pregnant women, especially during the first and second trimesters.

On the other hand, it has also been reported that piroxicam is associated with a reduction in the ability to conceive. The drug is excreted in milk and its safety during lactation has not been evaluated.

What are the possible side effects of piroxicam?

Like all medicines, this drug can cause short-term and long-term side effects. We’ll explain them, based on the number of affected patients in the following list:

• Common side effects (up to 1 in 10 patients): decrease in certain cells in the bloodstream, loss of appetite, high blood sugar levels, dizziness, headache, drowsiness, vertigo, ringing in the ears, abdominal discomfort, constipation, diarrhea, flatulence.
• Uncommon side effects (up to 1 in 100 patients): palpitations, swollen gums, reversible increase in creatinine levels, Stevens-Johnson syndrome, low blood sugar, and blurred vision.
• Very rare (up to 1 in 10,000 patients): toxic epidermal necrolysis, separation of the nail, skin reactions due to allergy to light, and urticaria, among others.
• Effects of unknown frequency: depression, sleep disturbances, hallucinations, insomnia, confusion, mood swings, nervousness, hair loss.

Despite the many side effects we have shown you, it should be noted that gastrointestinal symptoms are usually the most common. Most of the rest fall into unexpected severe reactions.

What happens if I miss a dose?

If you forget to take piroxicam, take it as soon as you can. As the doses must be taken in 24-hour intervals, there’s a lot of room for error and time to take the pill. However, if you skip one day’s dose altogether, don’t take 2 pills the next day to make up for it.

What should I do in case of an overdose?

In no case should the dose of 20 milligrams a day be exceeded. That is, an injection in the hospital setting or 1 tablet a day. In the event that the patient ingests more, the following symptoms may be experienced:

• Lack of energy and drowsiness
• Upset stomach, vomiting, and stomach pain
• Dark or tarry stools and brown vomit
• Difficulty breathing and eating

If you have taken more tablets than you should for any reason, go to the emergency room as soon as possible with the medicine in hand. In case of indisposition and lack of energy, call an ambulance and ask someone you know to accompany you.

How to store and dispose of this medicine

This medicine does not require special storage conditions, at least in its oral variant. Simply keep the pills in their original packaging, check the expiration date periodically and place the container out of the reach of children.

Finally, remember that you should not flush this drug, or any other, down the toilet or into the garbage, as this can cause serious long-term damage to the ecosystem.

A non-steroidal anti-inflammatory with many uses

As we have seen, piroxicam is a drug that has many uses, but they all have something in common: the reduction of pain and inflammation in both acute and chronic conditions. This drug is useful, above all, when it comes to managing the symptoms of arthritic pathologies.

Beyond the medication, you should keep in mind that piroxicam does not solve the underlying condition that causes the discomfort. The patient may need to undergo physiotherapeutic techniques to improve their condition.