Divon Rb

Uses

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.

Short-term treatment in healing and symptomatic relief of duodenal ulcers and erosive or ulcerative Gastroesophageal Reflux Disease (GERD).

Maintaining healing and reducing relapse rates of heartburn symptoms in patients with GERD.

Treatment of daytime and night time heartburn and other symptoms associated with GERD.

Long-term treatment of pathological hypersecretory conditions, including Zollinger Ellison Syndrome.

In combination with Amoxicillin and Clarithromycin to eradicate Helicobacter pylori.

Divon Rb is also used to associated treatment for these conditions: Actinic 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 miosisDuodenal Ulcer, Gastric Ulcer, Gastro-esophageal Reflux Disease (GERD), Heartburn, Helicobacter Pylori Infection, NSAID Associated Gastric Ulcers, Non-erosive Reflux Esophagitis Disease (NERD), Vomiting, Zollinger-Ellison Syndrome, Erosive reflux esophagitis

How Divon Rb works

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.

Rabeprazole belongs to a class of antisecretory compounds (substituted benzimidazole proton-pump inhibitors) that do not exhibit anticholinergic or histamine H2-receptor antagonist properties, but suppress gastric acid secretion by inhibiting the gastric H⁺/K⁺ATPase (hydrogen-potassium adenosine triphosphatase) at the secretory surface of the gastric parietal cell. Because this enzyme is regarded as the acid (proton) pump within the parietal cell, rabeprazole has been characterized as a gastric proton-pump inhibitor. Rabeprazole blocks the final step of gastric acid secretion. In gastric parietal cells, rabeprazole is protonated, accumulates, and is transformed to an active sulfenamide. When studied in vitro, rabeprazole is chemically activated at pH 1.2 with a half-life of 78 seconds.

Dosage

Divon Rb 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.

Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD): 20 mg to be taken once daily for 4 to 8 weeks. For those patients who have not healed after 8 weeks of treatment, an additional 8 week course may be considered.

Maintenance of Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD Maintenance): The recommended adult oral dose is 20 mg once daily.

Treatment of Symptomatic Gastroesophageal Reflux Disease (GERD):The recommended adult oral dose is 20 mg once daily for 4 weeks. If symptoms do not resolve completely after 4 weeks, an additional course of treatment may be considered.

Healing of Duodenal Ulcers:The recommended adult oral dose is 20 mg once daily after the morning meal for a period up to four weeks. Most patients with duodenal ulcer heal within four weeks. A few patients may require additional therapy to achieve healing.

Helicobacter pylori Eradication:To Reduce the Risk of Duodenal Ulcer Recurrence-

• Rabeprazole Sodium 20 mg Twice Daily for 7 Days
• Amoxicillin 1000 mg Twice Daily for 7 Days
• Clarithromycin 500 mg Twice Daily for 7 Days

All three medications should be taken twice daily with the morning and evening meals. It is important that patients comply with the full 7-day regimen.

Treatment of Pathological Hypersecretory Conditions Including Zollinger-Ellison Syndrome: The dosage of Rabeprazole Sodium in patients with pathologic hypersecretory conditions varies with the individual patient. The recommended adult oral starting dose is 60 mg once a day. Doses should be adjusted to individual patient needs and should continue for as long as clinically indicated. Some patients may require divided doses. Doses up to 100 mg QD and 60 mg BID have been administered. Some patients with Zollinger-Ellision syndrome have been treated continuously with Rabeprazole Sodium for up to one year.

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.

Rabeprazole Sodium may sometimes cause headache, diarrhoea, abdominal pain, vomiting, constipation, dry mouth, increased or decreased appetite, muscle pain, drowsiness and dizziness.

Toxicity

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 Rabeprazole Sodium to patients with mild to moderate liver impairment resulted in increased exposure and decreased elimination. Caution should be exercised in patients with severe hepatic impairment.

Interaction

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

Rabeprazole is metabolized by the Cytochrome P-450 (CYP-450) drug metabolizing enzyme system. Rabeprazole does not have clinically significant interactions with other drugs metabolized by the CYP-450 system,such as Warfarin and Theophylline given as single oral dose, Diazepam as a single intravenous dose, and Phenytoin given as a single intravenous dose. In normal subjects, co-administration of Rabeprazole 20 mg QD resulted in an approximately 30% decrease in the bioavailability of Ketoconazole and increase in the AUC and Cmax for digoxin of 90% and 29% respectively.

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.

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.

Absolute bioavailability is approximately 52%.

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.

1-2 hours (in plasma)

Clearance

Diclofenac has a plasma clearance 16 L/h.

Elimination Route

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.

Following a single 20 mg oral dose of 14C-labeled rabeprazole, approximately 90% of the drug was eliminated in the urine, primarily as thioether carboxylic acid; its glucuronide, and mercapturic acid metabolites.

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.

Rabeprazole is FDA Pregnancy Category B. No data is available on administration of Rabeprazole to pregnant women. However this drug should be used during pregnancy, only if clearly needed. There are no data on the excretion of Rabeprazole into the breast milk. A decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the benefit of the drug to the mother.

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

Rabeprazole Sodium is contraindicated in patient with known hypersensitivity to Rabeprazole or to any component in the product.

Special Warning

Use in pediatric patients: The safety and effectiveness of Rabeprazole in pediatric patients have not been established.

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.

There has been no experience with large overdoses with Rabeprazole. No specific antidote for Rabeprazole is known. Rabeprazole is extensively protein bound and is not readily dialyzable. In the event of overdosage, treatment should be symptomatic and supportive.

Storage Condition

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

Store below 25°C, protected from light and moisture. Keep all medicines out of the reach of the children.

Innovators Monograph

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