Phenylbutazone

Phenylbutazone is a Analgesic and Antipyretic belonging to Non-Steroidal anti-inflammatory Drug

Phenylbutazone is used in the treatment of rheumatoid disorder and gout.

Phenylbutazone is Well absorbed from GI tract and get distributed in Most body tissues and synovial spaces; protein binding: 98% with Hepatic metabolism and get excreted Via urine as metabolites (99%).

Phenylbutazone shows common side effects like vomiting, indigestion, flatulence, nausea, abdominal pain, constipation, epigastric pain, diarrhoea, large intestine carcinoma

Phenylbutazone is available in tablets and injection.

Phenylbutazone is available in India, Germany, Canada, France, USA.

Phenylbutazone binds to and inactivates prostaglandin H synthase and prostacyclin synthase through peroxide (H2O2) mediated deactivation. The reduced production of prostaglandin leads to reduced inflammation of the surrounding tissues.

Phenylbutazone is available in the form of tablets and injection.

Phenylbutazone is used in the treatment of rheumatoid disorder and gout.

Phenylbutazone is derived from pyrazolone and is an NSAID used only in acute conditions due to its toxicity. It has anti-inflammatory, antipyretic, uricosuric, and analgesic properties; these actions are due primarily to prostaglandin inhibition, leukocyte migration inhibition, and lysosomal enzyme stabilization.

Phenylbutazone is approved for use in the following clinical indications

rheumatoid disorder and gout.

Oral

Rheumatic disorders

Adult: Up to 600 mg daily in divided doses. Reduce dose to the lowest effective dose after 1-3 days. Usual max: Up to 1 wk.

Oral

Acute gout

Adult: Up to 800 mg daily may be needed. Reduce to the lowest effective dose after 1-3 days. Usual max duration: Up to 1 wk.

Phenylbutazone is available in the dosage strength of 100 mg, 200 mg/ml.

Phenylbutazone is available in the form of tablets and injection.

Take after eating and with a full glass of water to decrease gastric upset.

Phenylbutazone is contraindicated in patients with:

Phenylbutazone should not be administered to animals with serious hepatic, renal or cardiac pathology, or those with a history of blood dyscrasia.

• Use with caution in animals with a history of drug allergy.

Stop medication at the first sign of gastrointestinal upset, jaundice or blood dyscrasia. Authenticated cases of agranulocytosis associated with phenylbutazone have occured in man. Phenylbutazone induced blood dyscrasias have been reported in dogs. Throbocytopenia and leukopenia are early manifestations followed by nonregenerative anemia. The occurrence of this reaction is not dose depended and is unpredictable. To guard against this possibility, conduct routine blood counts at not more than 7 day intervals during the early course of therapy, and at intervals of not more than 14 days throughout the course of therapy. Any significant fall in the total white count, relative decrease in granulocytes or black or tarry stools should be regarded as a signal for immediate cessation of therapy and institution of appropriate treatment.

• When treating inflammatory conditions associated with infection, specific anti-infective therapy is required.

• Response to phenylbutazone therapy is prompt, usually occurring within 24 hours. If no significant clinical response is evident after 5 days of therapy, re-evaluate diagnosis and therapeutic regimen.

Phenylbutazone may cause liver problems, and using it with substantial quantities of ethanol may increase that risk.

Food may decrease the rate but not the extent of absorption. Phenylbutazone peak serum levels may be delayed if taken with food. Management: Administer with food or milk to minimize GI upset.

• Common Adverse Effects: Tachycardia, hypotension, myocarditis, atrial fibrillation, atrial flutter, angina, CHF, myocardial depression, pericardial effusion/pericarditis, dizziness

• Less Common Adverse effects: Toxic Epidermal Necrolysis, Cutaneous Vasculitis, Parotitis, GI Disorders, Anemia, Thrombocytopenia, Coagulopathy, Leukopenia, Neutropenia, Agranulocytosis, Granulocytopenia, Red Blood Cell Aplasia, Hepatitis, Primary Biliary Cirrhosis

• Rare Adverse Effects: Myoglobinuria, Glomerulonephritis, Renal Vasculitis, Pulmonary Edema, Pulmonary Vasculitis, SLE, and Lymphadenopathy.

May reduce phenytoin or warfarin metabolism and methotrexate excretion.

The common side effects of Phenylbutazone include the following :

Vomiting, Indigestion, Flatulence, Nausea, Abdominal Pain, Constipation, Epigastric Pain, Diarrhea, Large Intestine Carcinoma.

Abdominal pain, agitation, ataxia, chest pain, cholestatic jaundice, coagulopathy, colitis, coma, dermatitis, diarrhea, drowsiness, dyssomnia, erythema multiforme, exfoliative dermatitis, fecal discoloration, gastritis, hematuria, GI bleeding, hyperventilation, hypotension, hypothyroidism, jaundice, lichenoid eruptions, pemphigus, periarteritis nodosa, pericarditis, photosensitivity, respiratory arrest, rhabdomyolysis, seizures, stomatitis, toxic epidermal necrolysis, urine discoloration. Treatment is supportive; multiple doses of charcoal may be needed to reduce the risk for delayed toxicities.

• Pharmacodynamics

Phenylbutazone is a synthetic, pyrazolone derivative. It is a nonhormonal anti-inflammatory, antipyretic compound useful in the management of inflammatory conditions. The apparent analgesic effect is probably related mainly to the compound's anti-inflammatory properties and arise from its ability to reduce production of prostaglandin H and prostacyclin. Prostaglandins act on a variety of cells such as vascular smooth muscle cells causing constriction or dilation, on platelets causing aggregation or disaggregation and on spinal neurons causing pain. Prostacylcin causes vascular constriction platelet disaggregation

• Pharmacokinetics

Absorption: Oral: Well absorbed from GI tract.

Distribution: Most body tissues and synovial spaces; protein binding: 98%.

Metabolism: Hepatic, to Phenylbutazone and hydrPhenylbutazone; half-life: 50-100 hr (increases with hepatic impairment); time to peak: within 30-60 min.

Excretion: Via urine as metabolites (99%).

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1364710/
2. https://reference.medscape.com/drug/colestid-Phenylbutazone -342452
3. https://go.drugbank.com/drugs/DB00375
4. https://www.sciencedirect.com/topics/medicine-and-dentistry/Phenylbutazone
5. https://europepmc.org/article/med/6988203