Phenylbutazone

Phenylbutazone is a non-steroidal anti-inflammatory drug (NSAID) used in the treatment of fever, headache, muscle pain, arthralgia (pain in joint), and arthritis in humans and animals. It is often referred to as ‘Bute’. Phenylbutazone in India is manufactured by Therawin Formulations, and is available for bulk orders.

The drug was first produced by a Swiss firm, Giegy, and was approved for human use in 1949 for the treatment of gout and rheumatoid arthritis. It proved to be a less costly alternative to cortisone and appeared to provide symptomatic relief across humans and horses from the 1950s to the 2000s (1).

In the UK, it is sometimes used for the treatment of ankylosis spondylitis. In India, it is still available as a generic drug and is used to treat inflammation and pain for various conditions.

NSAIDs like Bute may be given orally or intravenously and the effect usually starts within 1-2 hours of administration.

What is the composition of Phenylbutazone?

Phenylbutazone is an antipyretic, anti-inflammatory, and analgesic drug. It is a synthetic, Pyrazolone derivative with a chemical formula of C₁₉H₂₀N₂O_2.

What is the mode of action?

Phenylbutazone works by blocking the release of certain chemical messengers called prostaglandins that cause inflammation (redness, swelling, pain, or heat) at the site of tissue damage or infection.

The drug binds and inactivates prostaglandin H synthase and prostacyclin synthase through Hydrogen Peroxide (H₂O₂) mediated deactivation. This leads to a decreased production of prostaglandins followed by subsequent reduction in inflammation of the affected tissues. This aminopyrine therapy is also responsible for lysosomal enzyme stabilization and leukocyte migration inhibition.

What are the uses of Phenylbutazone?

• In humans: For management of rheumatoid arthritis, ankylosis spondylitis, and gout.
• In dogs: Osteoarthritis
• In horses: As analgesia for pain relief and musculoskeletal disorders, including tendinitis, overuse, sprains, and arthritis, or for antipyresis (reduction in fever).

What are the side effects?

Some of the common side effects include:

• Visible water retention
• Vomiting
• Stomach cramps
• Epigastric distress
• Headache
• Dizziness
• Rashes
• Ringing in the ears
• Involuntary quivering

Sometimes, there may be more serious side effects with this drug as:

• Allergic reaction
• Skin sores, especially on the face and in the mouth
• Signs of bleeding like throwing up or coughing blood, blood in the urine, abnormal vaginal bleeding, bruises without a cause, etc.
• Yellowing of the skin
• Blurred vision
• Aplastic anemia
• Chest pain or pressure
• Heart failure
• Depression
• Loss of hearing
• Ulcerations
• Liver and kidney problems

Medication management

The use of Bute is generally reserved for short-term administration in some selected patients. The medication should not be prescribed if the patient is allergic to the drug or in individuals/pets with bleeding disorders, intestinal ulcers, or in females who are pregnant or lactating. It should be used cautiously in patients with kidney or heart diseases.

Previous case history, especially for those who had episodes of stroke should be taken into account. The administration of the medicine must be stopped at the first instance of liver problems like jaundice, blood dyscrasia, and gastrointestinal tract infections.

Routine blood tests must be done after every two weeks to check the count of WBCs as the medicine in known to cause agranulocytosis. Regular monitoring of protein levels, urine analysis, and protein levels should also be checked, especially when intended for long-term use.

Stop the therapy in case there is a significant drop in WBC count or granulocytes or there is formation of black or tarry stools. Countermeasures should be taken immediately in such cases. 

If the patient misses any dose, he or she can take it close to the time of the next dose. The patient should not take two doses at once or have extra doses.

Drug interactions and toxicity

The following medications should be used with caution with Phenylbutazone: ACE (angiotensin-converting-enzyme) inhibitors, corticosteroids, methotrexate, NSAIDs, penicillin G, sulfonamides, antidepressants, phenobarbital, warfarin, digoxin, misoprostol, diuretics, and others.

The patient should not consume alcohol while taking this drug.

If you suspect any overdose or toxicity with the drug, the patient should be closely monitored and emergency care should be given, if needed.

What is the veterinary use of Phenylbutazone?

It is usually given to pet animals (but not farm animals) for treating inflammation and pain. Phenylbutazone for dogs is recommended occasionally for the long-term pain management of osteoarthritis.

Always opt for oral administration for such long-term therapy. According to an experimental study in 8 dogs, bute and other NSAIDs like Indomethacin can be used to reduce pain and limping post-orthopaedic surgery in dogs (3).

For treatment in animals, especially in horses, the drug can be administered intravenously with 5 to 10mL per 450g of body weight. Intravenous injection can be administered up to a maximum of 5 days successively, followed by oral administration. Phenylbutazone is metabolized in animals usually within 8 hours so a third of the daily dose can be administered at an 8 hours interval. Some chronic conditions can correspond with phenylbutazone therapy but discontinuance of the treatment may cause a recurrence of the symptoms.

Stop Phenylbutazone use in animals in case of diarrhea, loss of blood from stomach or intestines, abdominal pain, labored breathing, agitation, confusion, movement disorder, skin rash, or any other symptoms mentioned above.

Availability of Phenylbutazone in India

In India Phenylbutazone is available in tablet form as:

Description: Round, White, Sugar-coated Tablets Pack:  500 Tablets	Description: Round, White/Yellow, Sugar-coated Tablets Pack:  500 Tablets
Description: Round, Black, Film-coated Tablets Pack:  1000 Tablets	Description: Round, Orange, Film-coated Tablets Pack: 2000 Tablets

Phenylbutazone tablet brand name

It is available as Winopyrine tablets from Therawin Formulations.

Apart from this Phenylbutazone Tablets are available for contract or third-party manufacturing as:

Description: Round/Oval,  Film/Sugar Coated Tablets
Pack:  Blister / Strip / Alu-Alu / Jars

Dosage for Phenylbutazone

The drug can be administered orally in the form of Phenylbutazone tablets, powder, paste, or granules. Each dose should be taken immediately after the meal. For usage in animals, it may also be given in the form of an intravenous injection.

For successful treatment, use a relatively higher dose in the first 48 hours then gradually maintain a low dose until you get the desired clinical response. The medicine usually takes effect quickly (within 24 hours) with immediate improvement in clinical signs. If no significant clinical response is seen within 5 days, then a revaluation of the diagnosis is needed.

How to store Phenylbutazone?

The drug should be stored at room temperature in a cool and dry place. Keep it out of reach of children and pets.

To learn more about ordering and contract manufacturing of Phenylbutazone in India, get in touch using the form on this page.