Parofen (Acetaminophen,Ibuprofen)

Uses

Acetaminophen is an analgesic drug used alone or in combination with opioids for pain management, and as an antipyretic agent.

In general, acetaminophen is used for the treatment of mild to moderate pain and reduction of fever. It is available over the counter in various forms, the most common being oral forms.

Acetaminophen injection is indicated for the management of mild to moderate pain, the management of moderate to severe pain with adjunctive opioid analgesics, and the reduction of fever.

Because of its low risk of causing allergic reactions, this drug can be administered in patients who are intolerant to salicylates and those with allergic tendencies, including bronchial asthmatics. Specific dosing guidelines should be followed when administering acetaminophen to children.

Ibuprofen is used

• For the treatment of sign and symptoms of rheumatoid arthritis, ankylosing spondylitis, osteoarthritis and other non-rheumatoid arthropathies,
• For the treatment of non-articular rheumatic conditions, such as frozen shoulder, bursitis, tendinitis, tenosynovitis and low back pain,
• For the treatment of soft tissue injuries such as sprain, strain and post operative pain
• For the treatment of dysmenorrhoea,
• For the treatment of dental pain.
• For the treatment of cold & fever.

Parofen (Acetaminophen,Ibuprofen) is also used to associated treatment for these conditions: Acute Gouty Arthritis, Acute Musculoskeletal Pain, Allergies, Ankylosing Spondylitis (AS), Arthritis, Chills, Cold, Cold Symptoms, Common Cold, Common Cold/Flu, Cough, Cough caused by Common Cold, Coughing caused by Flu caused by Influenza, Dyskinesia of the Biliary Tract, Dyskinesia of the Urinary Tract, Febrile Convulsions, Febrile Illness Acute, Fever, Fibromyalgia Syndrome, Flu caused by Influenza, Headache, Joint dislocations, Menstrual Distress (Dysmenorrhea), Mild pain, Muscle Inflammation, Muscle Injuries, Muscle Spasms, Musculoskeletal Pain, Nasal Congestion, Neuralgia, Osteoarthritis (OA), Pain, Pollen Allergy, Postoperative pain, Premenstrual cramps, Rheumatoid Arthritis, Rhinopharyngitis, Rhinorrhoea, Severe Pain, Sinusitis, Soreness, Muscle, Spasms, Spastic Pain of the Gastrointestinal Tract, Sprains, Tension Headache, Toothache, Upper Respiratory Tract Infection, Whiplash Syndrome, Acute Torticollis, Mild to moderate pain, Minor aches and pains, Minor pain, Moderate Pain, Airway secretion clearance therapy, Antispasmodic, BronchodilationAnkylosing Spondylitis (AS), Common Cold, Cystic Fibrosis (CF), Fever, Gastric Ulcer, Gouty Arthritis, Headache, Insomnia, Juvenile Idiopathic Arthritis (JIA), Menstrual Distress (Dysmenorrhea), Migraine, Mild pain, Nasal Congestion, Osteoarthritis (OA), Pain, Pain, Acute, Pain, Inflammatory, Patent Ductus Arteriosus (PDA), Pericarditis, Primary Dysmenorrhoea, Rheumatoid Arthritis, Severe Pain, Sinus pressure, Mild to moderate pain, Minor aches and pains, Moderate Pain

How Parofen (Acetaminophen,Ibuprofen) works

According to its FDA labeling, acetaminophen's exact mechanism of action has not been fully established - despite this, it is often categorized alongside NSAIDs (nonsteroidal anti-inflammatory drugs) due to its ability to inhibit the cyclooxygenase (COX) pathways. It is thought to exert central actions which ultimately lead to the alleviation of pain symptoms.

One theory is that acetaminophen increases the pain threshold by inhibiting two isoforms of cyclooxygenase, COX-1 and COX-2, which are involved in prostaglandin (PG) synthesis. Prostaglandins are responsible for eliciting pain sensations. Acetaminophen does not inhibit cyclooxygenase in peripheral tissues and, therefore, has no peripheral anti-inflammatory effects. Though acetylsalicylic acid (aspirin) is an irreversible inhibitor of COX and directly blocks the active site of this enzyme, studies have shown that acetaminophen (paracetamol) blocks COX indirectly. Studies also suggest that acetaminophen selectively blocks a variant type of the COX enzyme that is unique from the known variants COX-1 and COX-2. This enzyme has been referred to as COX-3. The antipyretic actions of acetaminophen are likely attributed to direct action on heat-regulating centers in the brain, resulting in peripheral vasodilation, sweating, and loss of body heat. The exact mechanism of action of this drug is not fully understood at this time, but future research may contribute to deeper knowledge.

The exact mechanism of action of ibuprofen is unknown. However, ibuprofen is considered an NSAID and thus it is a non-selective inhibitor of cyclooxygenase, which is an enzyme involved in prostaglandin (mediators of pain and fever) and thromboxane (stimulators of blood clotting) synthesis via the arachidonic acid pathway.

Ibuprofen is a non-selective COX inhibitor and hence, it inhibits the activity of both COX-1 and COX-2. The inhibition of COX-2 activity decreases the synthesis of prostaglandins involved in mediating inflammation, pain, fever, and swelling while the inhibition of COX-1 is thought to cause some of the side effects of ibuprofen including GI ulceration.

Dosage

Parofen (Acetaminophen,Ibuprofen) dosage

Oral Administrations-

For Children:

• 20 mg per kg body weight daily in divided doses. In children weighing less than 30 kg the total daily dosage should not exceed 500 mg. If gastrointestinal disturbances occur Ibuprofenshould be given with food or milk.
• 1-2 years: 1/2 tea spoonful (2.5 ml) 3-4 times daily;
• 3-7 years: 1 tea spoonful (5 ml) 3-4 times daily;
• 8-12 years: 2 tea spoonful (10 ml) 3-4 times daily. Ibuprofenis not recommended for children under 1 year.

For adult:

• For arthritic pain: The dosage range is from 0.9 to 2.4 g per day. The usual dose is 400 mg, 3-4 times per day, preferably after food. The dose may be raised to a maximum of 2.4 g daily depending on the severity of symptom at the time of initiating drug therapy or as patients fail to respond. After a satisfactory response has been achieved the patients dose should be reviewed and adjusted as required and tapered gradually.
• For mild to moderate pain: 400 mg 6 hourly or as demanded by the condition.
• For dysmenorrhoea: 400 mg every 4 hours or as demanded by the condition.

Topical Administrations-

Pain and inflammation associated with musculoskeletal and joint disorder: As 5% cream, foam, gel, spray soln or 10% gel: Apply onto affected area.

Side Effects

Usually Ibuprofen has a low incidence of side effects. The most frequent side effects are gastrointestinal disturbances. Peptic ulceration and gastrointestinal bleeding have occasionally been reported. Other side effects include headache, dizziness, nervousness, skin rash, pruritus, drowsiness, insomnia, blurred vision and other ocular reactions, hypersensitivity reaction, abnormal liver function test, impairment of renal function, agranulocytosis and thrombocytopenia.

Toxicity

LD50 = 338 mg/kg (oral, mouse); LD50 = 1944 mg/kg (oral, rat)

Overdose and liver toxicity

Acetaminophen overdose may be manifested by renal tubular necrosis, hypoglycemic coma, and thrombocytopenia. Sometimes, liver necrosis can occur as well as liver failure. Death and the requirement of a liver transplant may also occur. Metabolism by the CYP2E1 pathway releases a toxic acetaminophen metabolite known as N-acetyl-p-benzoquinoneimine(NAPQI). The toxic effects caused by this drug are attributed to NAPQI, not acetaminophen alone.

Carcinogenesis

Long-term studies in mice and rats have been completed by the National Toxicology Program to study the carcinogenic risk of acetaminophen. In 2-year feeding studies, F344/N rats and B6C3F1 mice consumed a diet containing acetaminophen up to 6,000 ppm. Female rats showed evidence of carcinogenic activity demonstrated by a higher incidence of mononuclear cell leukemia at doses 0.8 times the maximum human daily dose (MHDD). No evidence of carcinogenesis in male rats (0.7 times) or mice (1.2 to 1.4 times the MHDD) was noted. The clinical relevance of this finding in humans is unknown.

Mutagenesis

Acetaminophen was not found to be mutagenic in the bacterial reverse mutation assay (Ames test). Despite this finding, acetaminophen tested positive in the in vitro mouse lymphoma assay as well as the in vitro chromosomal aberration assay using human lymphocytes. In published studies, acetaminophen has been reported to be clastogenic (disrupting chromosomes) when given a high dose of 1,500 mg/kg/day to the rat model (3.6 times the MHDD). No clastogenicity was observed at a dose of 750 mg/kg/day (1.8 times the MHDD), indicating that this drug has a threshold before it may cause mutagenesis. The clinical relevance of this finding in humans is unknown.

Impairment of Fertility

In studies conducted by the National Toxicology Program, fertility assessments have been performed in Swiss mice in a continuous breeding study. No effects on fertility were seen.

Use in pregnancy and nursing

The FDA label for acetaminophen considers it a pregnancy category C drug, meaning this drug has demonstrated adverse effects in animal studies. No human clinical studies in pregnancy have been done to this date for intravenous acetaminophen. Use acetaminophen only when necessary during pregnancy. Epidemiological data on oral acetaminophen use in pregnant women demonstrate no increase in the risk of major congenital malformations. While prospective clinical studies examining the results of nursing with acetaminophen use have not been conducted, acetaminophen is found secreted in human milk at low concentrations after oral administration. Data from more than 15 nursing mothers taking acetaminophen was obtained, and the calculated daily dose of acetaminophen that reaches the infant is about 1 to 2% of the maternal dose. Caution should be observed when acetaminophen is taken by a nursing woman.

The symptoms of overdose are presented in individuals that consumed more than 99 mg/kg. Most common symptoms of overdose are abdominal pain, nausea, vomiting, lethargy, vertigo, drowsiness (somnolence), dizziness and insomnia. Other symptoms of overdose include headache, loss of consciousness, tinnitus, CNS depression, convulsions and seizures. May rarely cause metabolic acidosis, abnormal hepatic function, hyperkalemia, renal failure, dyspnea, respiratory depression, coma, acute renal failure, and apnea (primarily in very young pediatric patients).

The reported LD50 of ibuprofen is of 636 mg/kg in rat, 740 mg/kg in mouse and 495 mg/kg in guinea pig.

Precaution

Ibuprofen should be given with caution to patients with bleeding disorders, cardiovascular diseases, peptic ulceration or a history of such ulceration and in those who are receiving coumarin anticoagulants and in patients with renal or hepatic impairment.

Interaction

Increased risk of GI bleeding with warfarin, corticosteroids, SSRIs and aspirin. May reduce the natriuretic effects of diuretics. Reduced antihypertensive effect of ACE inhibitors and angiotensin II receptor antagonists. May increase toxicity of lithium and methotrexate. Increased nephrotoxicity with ciclosporin and tacrolimus.

Volume of Distribution

Volume of distribution is about 0.9L/kg. 10 to 20% of the drug is bound to red blood cells. Acetaminophen appears to be widely distributed throughout most body tissues except in fat.

The apparent volume of distribution of ibuprofen is of 0.1 L/kg.

Elimination Route

Acetaminophen has 88% oral bioavailability and reaches its highest plasma concentration 90 minutes after ingestion. Peak blood levels of free acetaminophen are not reached until 3 hours after rectal administration of the suppository form of acetaminophen and the peak blood concentration is approximately 50% of the observed concentration after the ingestion of an equivalent oral dose (10-20 mcg/mL).

The percentage of a systemically absorbed rectal dose of acetaminophen is inconsistent, demonstrated by major differences in the bioavailability of acetaminophen after a dose administered rectally. Higher rectal doses or an increased frequency of administration may be used to attain blood concentrations of acetaminophen similar to those attained after oral acetaminophen administration.

It is very well absorbed orally and the peak serum concentration can be attained in 1 to 2 hours after extravascular administration. When ibuprofen is administered immediately after a meal there is a slight reduction in the absorption rate but there is no change in the extent of the absorption.

When orally administered, the absorption of ibuprofen in adults is very rapidly done in the upper GI tract. The average Cmax, Tmax and AUC ranges around 20 mcg/ml, 2 h and 70 mcg.h/ml. These parameters can vary depending on the enantiomer form, route, and dose of administration.

Half Life

The half-life for adults is 2.5 h after an intravenous dose of 15 mg/kg. After an overdose, the half-life can range from 4 to 8 hours depending on the severity of injury to the liver, as it heavily metabolizes acetaminophen.

The serum half-life of ibuprofen is 1.2-2 hours. In patients with a compromised liver function, the half-life can be prolonged to 3.1-3.4 hours.

Clearance

Adults: 0.27 L/h/kg following a 15 mg/kg intravenous (IV) dose. Children: 0.34 L/h/kg following a 15 mg/kg intravenous (IV dose).

The clearance rate ranges between 3-13 L/h depending on the route of administration, enantiomer type and dosage.

Elimination Route

Acetaminophen metabolites are mainly excreted in the urine. Less than 5% is excreted in the urine as free (unconjugated) acetaminophen and at least 90% of the administered dose is excreted within 24 hours.

Ibuprofen is rapidly metabolized and eliminated in the urine thus, this via accounts for more than 90% of the administered dose. It is completely eliminated in 24 hours after the last dose and almost all the administered dose goes through metabolism, representing about 99% of the eliminated dose. The biliary excretion of unchanged drug and active phase II metabolites represents 1% of the administered dose.

In summary, ibuprofen is excreted as metabolites or their conjugates. The elimination of ibuprofen is not impaired by old age or the presence of renal impairment.

Pregnancy & Breastfeeding use

Ibuprofen is not recommended during pregnancy or for use in nursing mothers.

Contraindication

Ibuprofen should not be given to patients with hypersensitivity to lbuprofen and to individuals who show nasal polyps, angioedema, bronchospastic reactivity to aspirin or other non-steroidal anti-inflammatory drug. Ibuprofen is contraindicated in patients with active or previous peptic ulceration & gastro-intestinal ulceration or bleeding.

Acute Overdose

Gastric lavage, correction of blood electrolytes (if necessary). There is no specific antidote for Ibuprofen

Storage Condition

Keep in a cool & dry place. Keep out of the reach of children.

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