Oronac Mr

Uses

Chlorzoxazone is a drug with muscle relaxant properties that is used as an adjunct to physical therapy and analgesics to treat stiffness and pain caused by a variety of musculoskeletal conditions.

For the relief of discomfort associated with acute painful musculoskeletal conditions.

Diclofenac Sodium ophthalmic preparation is used for-

• Inhibition of miosis during cataract surgery.
• Post-operative inflammation after cataract surgery and other ocular surgical procedures.
• Pre-operative and post-operative prevention of cystoid macular edema (CME) associated with lens extraction & intraocular lens implantation.
• Post-traumatic inflammation in penetrating and non- penetrating wounds (as an adjuvant to local anti-infective therapy).
• Non-infected chronic conjunctivitis, keratoconjunctivitis.

Paracetamol IV is used for the management of mild to moderate pain, the management of moderate to severe pain with adjunctive opioid analgesics, the reduction of fever.

Paracetamol is a non-salicylate antipyretic and non-opioid analgesic agent. Paracetamol IV injection is a sterile, clear, colorless, non pyrogenic, isotonic formulation of Paracetamol intended for intravenous infusion.

Oronac Mr is also used to associated treatment for these conditions: Pain, Moderate Muscle Spasm, Severe Muscle SpasmActinic Keratosis (AK), Acute Arthritis, Acute Gouty Arthritis, Acute Migraine, Acute Musculoskeletal Pain, Ankylosing Spondylitis (AS), Common Cold, Fever, Gouty Arthritis, Inflammation, Inflammatory Disease of the Oral Cavity, Inflammatory Disease of the throat, Inflammatory Reaction of the Nerve, Joint Pain, Juvenile Idiopathic Arthritis (JIA), Menstrual Distress (Dysmenorrhea), Muscle Inflammation, Ocular Inflammation, Operation site inflammation, Osteoarthritis (OA), Osteoarthritis of the Knee, Pain, Pain, Nerve, Pericarditis, Photophobia, Postoperative pain, Primary Dysmenorrhoea, Radicular Pain, Rheumatic Pain, Rheumatism, Rheumatoid Arthritis, Seasonal Allergic Conjunctivitis, Soreness, Muscle, Spinal pain, Tendon pain, Vertebral column pain, Acute Musculoskeletal injury, Acute, moderate, severe Pain, Inflammatory, Localized soft tissue rheumatism, Mild to moderate joint pain, Mild to moderate pain, Minor pain, Perioperative miosisAcute 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, Bronchodilation

How Oronac Mr works

Chlorzoxazone inhibits degranulation of mast cells, subsequently preventing the release of histamine and slow-reacting substance of anaphylaxis (SRS-A), mediators of type I allergic reactions. Chlorzoxazone also may reduce the release of inflammatory leukotrienes. Chlorzoxazone may act by inhibiting calcium and potassium influx which would lead to neuronal inhibition and muscle relaxation. Data available from animal experiments as well as human study indicate that chlorzoxazone acts primarily at the level of the spinal cord and subcortical areas of the brain where it inhibits multisynaptic reflex arcs involved in producing and maintaining skeletal muscle spasm

Diclofenac inhibits cyclooxygenase-1 and -2, the enzymes responsible for production of prostaglandin (PG) G₂ which is the precursor to other PGs. These molecules have broad activity in pain and inflammation and the inhibition of their production is the common mechanism linking each effect of diclofenac.

PGE₂ is the primary PG involved in modulation of nociception. It mediates peripheral sensitization through a variety of effects. PGE₂ activates the G_q-coupled EP₁ receptor leading to increased activity of the inositol trisphosphate/phospholipase C pathway. Activation of this pathway releases intracellular stores of calcium which directly reduces action potential threshold and activates protein kinase C (PKC) which contributes to several indirect mechanisms. PGE₂ also activates the EP₄ receptor, coupled to G_s, which activates the adenylyl cyclase/protein kinase A (AC/PKA) signaling pathway. PKA and PKC both contribute to the potentiation of transient receptor potential cation channel subfamily V member 1 (TRPV1) potentiation, which increases sensitivity to heat stimuli. They also activate tetrodotoxin-resistant sodium channels and inhibit inward potassium currents. PKA further contributes to the activation of the P2X3 purine receptor and sensitization of T-type calcium channels. The activation and sensitization of depolarizing ion channels and inhibition of inward potassium currents serve to reduce the intensity of stimulus necessary to generate action potentials in nociceptive sensory afferents. PGE₂ act via EP₃ to increase sensitivity to bradykinin and via EP₂ to further increase heat sensitivity. Central sensitization occurs in the dorsal horn of the spinal cord and is mediated by the EP₂ receptor which couples to G_s. Pre-synaptically, this receptor increases the release of pro-nociceptive neurotransmitters glutamate, CGRP, and substance P. Post-synaptically it increases the activity of AMPA and NMDA receptors and produces inhibition of inhibitory glycinergic neurons. Together these lead to a reduced threshold of activating, allowing low intensity stimuli to generate pain signals. PGI₂ is known to play a role via its G_s-coupled IP receptor although the magnitude of its contribution varies. It has been proposed to be of greater importance in painful inflammatory conditions such as arthritis. By limiting sensitization, both peripheral and central, via these pathways NSAIDs can effectively reduce inflammatory pain.

PGI₂ and PGE₂ contribute to acute inflammation via their IP and EP₂ receptors. Similarly to β adrenergic receptors these are G_s-coupled and mediate vasodilation through the AC/PKA pathway. PGE₂ also contributes by increasing leukocyte adhesion to the endothelium and attracts the cells to the site of injury. PGD₂ plays a role in the activation of endothelial cell release of cytokines through its DP₁ receptor. PGI₂ and PGE₂ modulate T-helper cell activation and differentiation through IP, EP₂, and EP₄ receptors which is believed to be an important activity in the pathology of arthritic conditions. By limiting the production of these PGs at the site of injury, NSAIDs can reduce inflammation.

PGE₂ can cross the blood-brain barrier and act on excitatory G_q EP₃ receptors on thermoregulatory neurons in the hypothalamus. This activation triggers an increase in heat-generation and a reduction in heat-loss to produce a fever. NSAIDs prevent the generation of PGE₂ thereby reducing the activity of these neurons.

Dosage

Oronac Mr dosage

Ophthalmic (Adult)-

• Postoperative ocular inflammation: Instill into the appropriate eye 4 times daily starting 24 hr after surgery for up to 28 days.
• Inflammation and discomfort after strabismus surgery: Instill 1 drop 4 times daily for the 1st wk; then tid in the 2nd wk, bid in the 3rd wk, and as required for the 4th wk.
• Pain and discomfort after radial keratotomy: Instill 1 drop before surgery followed by 1 drop immediately after surgery, and then 1 drop 4 times daily for up to 2 days.
• Pain after accidental trauma: Instill 1 drop 4 times daily for up to 2 days.
• Control of inflammation after argon laser trabeculoplasty:Instill 1 drop 4 times during the 2 hr before procedure followed by 1 drop 4 times daily, up to 7 days after procedure.
• Prophylaxis of intra-operative miosis: Instill into appropriate eye 4 times w/in 2 hr before surgery.
• Post-photorefractive keratectomy pain:Instill into the affected eye twice, an hr before surgery, then 1 drop twice at 5-min intervals immediately after surgery, then every 2-5 hr while awake for up to 24 hr.
• Seasonal allergic conjunctivitis:Instill 1 drop before surgery followed by 1 drop immediately after surgery, and then 1 drop 4 times daily for up to 2 days.

Adults and adolescents weighing 50 kg and over: the recommended dosage of Paracetamol IV is 1000 mg every 6 hours or 650 mg every 4 hours, with a maximum single dose of Paracetamol IV of 1000 mg, a minimum dosing interval of 4 hours, and a maximum daily dose of Paracetamol of 4000 mg per day.

Adults and adolescents weighing under 50 kg: the recommended dosage of Paracetamol IV is 15 mg/kg every 6 hours or 12.5 mg/kg every 4 hours, with a maximum single dose of Paracetamol IV of 15 mg/kg, a minimum dosing interval of 4 hours, and a maximum daily dose of Paracetamol of 75 mg/kg per day.

Children >2 to 12 years of age: the recommended dosage of Paracetamol IV is 15 mg/kg every 6 hours or 12.5 mg/kg every 4 hours, with a maximum single dose of Paracetamol IV of 15 mg/kg, a minimum dosing interval of 4 hours, and a maximum daily dose of Paracetamol of 75 mg/kg per day.

Side Effects

Mild to moderate burning sensation in 5-15% patients which is transient in nature and almost never necessitated discontinuation of treatment. Other less common side-effects are sensitivity to light, bad taste, feeling of pressure, allergic reactions etc.

As all paracetamol products, adverse drug reactions are rare (>1/10000, <1/1000) or very rare (<1/10000). Frequent adverse reactions at injection site have been reported during clinical trials (pain and burning sensation). Very rare cases of hypersensitivity reactions ranging from simple skin rash or urticaria to anaphylactic shock have been reported and require discontinuation of treatment. Cases of erythema, flushing, pruritus and tachycardia have been reported.

Toxicity

Oral, mouse: LD₅₀ = 440 mg/kg; Oral, rat: LD₅₀ = 763 mg/kg; Symptoms of overdose include diarrhea, dizziness, drowsiness, headache, light-headedness, nausea, and vomiting.

Symptoms of overdose include lethargy, drowsiness, nausea, vomiting, and epigastric pain, and gastrointestinal bleeding. Hypertension, acute renal failure, respiratory depression and coma occur rarely. In case of overdose, provide supportive care and consider inducing emesis and administering activated charcoal if overdose occurred less than 4 hours prior.

Precaution

Diclofenac eye drops may mask the signs of infection. So physicians should be alert to the development of infections in patients receiving the drug. During prolonged use, it is recommended that physicians conduct periodic examinations of the eye, including measurement of the intraocular pressure. Contact lenses should not be worn during treatment.

Administration of Paracetamol in doses higher than recommended may result in hepatic injury, including the risk of severe hepatotoxicity and death. Do not exceed the maximum recommended daily dose of Paracetamol. Use caution when administering Paracetamol in patients with the following conditions: hepatic impairment or active hepatic disease, alcoholism, chronic malnutrition, severe hypovolemia (e.g., due to dehydration or blood loss), or severe renal impairment (creatinine clearance < 30 ml/min). There were infrequent reports of life-threatening anaphylaxis requiring emergent medical attention. Discontinue Paracetamol IV immediately if symptoms associated with allergy or hypersensitivity occurs. Do not use Paracetamol IV in patients with Paracetamol allergy.

Interaction

No drug interaction is reported. There should be at least 5 minutes interval when another ophthalmic solution (e.g., steroid) is given.

Volume of Distribution

Diclofenac has a total volume of distribution of 5-10 L or 0.1-0.2 L/kg. The volume of the central compartment is 0.04 L/kg. Diclofenac distributes to the synovial fluid reaching peak concentration 2-4h after administration. There is limited crossing of the blood brain barrier and cerebrospinal fluid concentrations only reach 8.22% of plasma concentrations. Doses of 50 mg delivered via intramuscular injection produced no detectable diclofenac concentrations in breast milk, however metabolite concentrations were not investigated. Diclofenac has been shown to cross the placenta in mice and rats but human data is unavailable.

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.

Elimination Route

Diclofenac is completely absorbed from the GI tract but likely undergoes significant first pass metabolism with only 60% of the drug reaching systemic circulation unchanged . Many topical formulations are absorbed percutaneous and produce clinically significant plasma concentrations. Absorption is dose proportional over the range of 25-150 mg. Tmax varies between formulations with the oral solution reaching peak plasma concentrations in 10-40min, the enteric coated tablet in 1.5-2h, and the sustained- and extended-release formulations prolonging Tmax even further. Administration with food has no significant effects on AUC but does delay Tmax to 2.5-12h.

Half Life

The terminal half-life of diclofenac is approximately 2 h, however the apparent half-life including all metabolites is 25.8-33 h.

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.

Clearance

Diclofenac has a plasma clearance 16 L/h.

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).

Elimination Route

Chlorzoxazone is rapidly metabolized and is excreted in the urine, primarily in a conjugated form as the glucuronide.

Diclofenac is mainly eliminated via metabolism. Of the total dose, 60-70% is eliminated in the urine and 30% is eliminated in the feces. No significant enterohepatic recycling occurs.

Pregnancy & Breastfeeding use

The safety of Diclofenac eye drops in pregnancy & lactation has not been established and its use therefore is not recommended unless the potential benefit to the mother outweighs the possible risk to the child.

Pregnancy Category C. There are no studies of intravenous Paracetamol in pregnant women; however, epidemiological data on oral Paracetamol use in pregnant women show no increased risk of major congenital malformations. Animal reproduction studies have not been conducted with IV Paracetamol and it is not known whether Paracetamol IV can cause fetal harm when administered to a pregnant woman. Paracetamol IV should be given to a pregnant woman only if clearly needed. There are no adequate and well-controlled studies with Paracetamol IV during labor and delivery; therefore, it should be used in such settings only after a careful benefit-risk assessment. While studies with Paracetamol IV have not been conducted, Paracetamol is secreted in human milk in small quantities after oral administration.

Contraindication

Hypersensitivity to any of the components Like other non steroidal anti-inflammatory agents, Diclofenac Sodium eye drops is contraindicated in patients in whom attacks of asthma, urticaria or acute rhinitis have been observed following application of acetyl salicylic acid or other cyclo-oxygenase inhibitors

Paracetamol is contraindicated in patients with known hypersensitivity to its active ingredient or to any of the excipients in the intravenous formulation. Also contraindicated in patients with severe hepatic impairment or severe active liver disease

Special Warning

Pediatric Use: The safety and effectiveness of Paracetamol IV for the treatment of acute pain and fever in pediatric patients ages 2 years and older is supported by evidence from adequate and well-controlled studies of Paracetamol IV in adults.

Geriatric use: No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger patients.

Patients with Hepatic Impairment: Paracetamol is contraindicated in patients with severe hepatic impairment or severe active liver disease and should be used with caution in patients with hepatic impairment or active liver disease. A reduced total daily dose of Paracetamol may be warranted.

Patients with Renal Impairment: In cases of severe renal impairment (creatinine clearance < 30 ml/min), longer dosing intervals and a reduced total daily dose of Paracetamol may be warranted.

Acute Overdose

Accidental ingestion of Diclofenac Sodium presents virtually no risk of unwanted effects, since one 5 ml bottle of eye drop solution contains only 5 mg of Diclofenac Sodium, which is equivalent to about 3% of the recommended maximum oral dose for adults.

Storage Condition

Close the bottle immediately after use. Do not use for more than four weeks after opening. Store at room temperature.

Store in a cool & dry place & away from children. For single use only. The product should be used within 6 hours after opening. Do not refrigerate or freeze.

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