Actions of Diclofenac in details
Percutaneous anti-inflammatory agent.
Diclofenac is an anti-inflammatory and analgesic preparation for topical application. Its active substance corresponds to 1% Diclofenac. The white, creamy, non-greasy preparation is easy to rub into the skin, and its aqueous-alcoholic base gives it a soothing and cooling effect.
Diclofenac has been shown in experiments to inhibit prostaglandin biosynthesis and this is regarded as an important factor in its mechanism of action.
In inflammation of traumatic or rheumatic origin, Diclofenac has been shown to relieve pain, reduce oedema and shorten the time to return of normal function.
Pharmacokinetics: Absorption: The amount of Diclofenac absorbed through the skin is proportional to the contact time and skin area covered with Diclofenac and depends on the total topical dose and on skin hydration. About 6% of the active substance is absorbed after topical application of Diclofenac 2.5 g/500 cm2, as determined by reference to total renal elimination compared with Voltaren tablets. Absorption of Diclofenac increases 3-fold if an occlusive dressing is applied for 10 hrs.
Distribution: Diclofenac can be detected in the plasma, synovial tissue and synovial fluid after topical application of Diclofenac to the wrists and knees. Peak plasma concentrations of Diclofenac are about 100 times lower after topical application of Diclofenac than after oral administration of Voltaren tablet. 99.7% of Diclofenac binds to serum proteins, mainly to albumin (99.4%).
Metabolism: Biotransformation of Diclofenac takes place partly by glucuronidation of the intact molecule, but mainly by single or multiple hydroxylation resulting in several phenolic metabolites, most of which are converted to glucuronide conjugates. Two of these phenolic metabolites are biologically active, but to a much lesser extent than Diclofenac.
Elimination: Total systemic clearance of Diclofenac from the plasma is 263 ± 56 mL/min (mean value ± standard deviation). The terminal plasma half-life is 1-2 hrs. Four of the metabolites, including the 2 active metabolites, also have a short plasma half-life (1-3 hrs). One metabolite, 3'-hydroxy-4'-methoxy-Diclofenac, has a much longer half-life, but this metabolite is virtually inactive.
Diclofenac and its metabolites are excreted mainly in the urine.
Kinetics in Special Clinical Situations: No accumulation of Diclofenac and its metabolites should occur in patients with renal insufficiency.
In patients with chronic hepatitis or nondecompensated liver cirrhosis, the kinetics and metabolism of Diclofenac are the same as in patients without liver disease.
How should I take Diclofenac?
Take Diclofenac exactly as directed on the label, or as prescribed by your doctor. Your doctor may occasionally change your dose to make sure you get the best results. Do not take this medicine in larger amounts or for longer than recommended. Use the lowest dose that is effective in treating your condition.
For treatment of pain or primary dysmenorrhea the recommended dosage of Diclofenac is 50 mg three times daily. In some patients an initial dose of 100 mg of Diclofenac, followed by 50 mg doses, may provide better relief.
For the relief of osteoarthritis the recommended dosage of Diclofenac is 100-150 mg/day in divided doses, i.e. 50 mg two or three times a day.
For the relief of rheumatoid arthritis the recommended dosage is 150-200 mg/day in divided doses, i.e. 50 mg three or four times a day.
Different formulations of Diclofenac, Voltaren (Diclofenac tablets) and Diclofenac (Diclofenac potassium immediate-release tablets) are not necessarily equivalent in strength even if the milligram strength is the same.
If you use Diclofenac long-term, you may need frequent medical tests.
Store at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use.
Read all patient information, medication guides, and instruction sheets provided to you. Ask your doctor or pharmacist if you have any questions.
Diclofenac administration
Take exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.
If you switch brands of Diclofenac, your dose needs may change. Follow your doctor's instructions about how much medicine to take.
Do not crush, chew, or break an extended-release tablet. Swallow it whole. Breaking the pill may cause too much of the drug to be released at one time.
Dissolve the Diclofenac powder (Diclofenac) with 1 to 2 ounces of water. Do not use any other type of liquid. Stir this mixture and drink all of it right away. Diclofenac powder works best if you take it on an empty stomach.
Call your doctor if your headache does not completely go away after taking Diclofenac. Do not take a second dose of Diclofenac powder without your doctor's advice.
Do not crush, chew, or break an enteric-coated pill. Swallow the pill whole. The enteric-coated pill has a special coating to protect your stomach. Breaking the pill could damage this coating.
If you use this medication long-term, your liver function will need to be checked with frequent blood tests. Visit your doctor regularly.
Store at room temperature away from moisture and heat.
Diclofenac pharmacology
Mechanism Of Action
Diclofenac has analgesic, anti-inflammatory, and antipyretic properties.
The mechanism of action of Diclofenac, like that of other NSAIDs, is not completely understood but involves inhibition of cyclooxygenase (COX-1 and COX-2).
Diclofenac is a potent inhibitor of prostaglandin synthesis in vitro. Diclofenac concentrations reached during therapy have produced in vivo effects. Prostaglandins sensitize afferent nerves and potentiate the action of bradykinin in inducing pain in animal models. Prostaglandins are mediators of inflammation. Because Diclofenac is an inhibitor of prostaglandin synthesis, its mode of action may be due to a decrease of prostaglandins in peripheral tissues.
Pharmacodynamics
The effect of Diclofenac on QTc prolongation was evaluated in a randomized, double-blind, positive (moxifloxacin 400 mg) - and placebo-controlled crossover study in healthy subjects. A total of 70 subjects was administered Diclofenac 37.5 mg and 75 mg. In a study with demonstrated ability to detect small effects, the upper bound of the 90% confidence interval for the largest placebo-adjusted, baseline-corrected QTc based on Fridericia correction method (QTcF) was below 10 ms, the threshold for regulatory concern.
Pharmacokinetics
Following intravenous administration of Diclofenac to healthy volunteers, plasma concentrations of Diclofenac exceed that of immediate-release oral Diclofenac for the first 45 minutes reaching a maximum of 4.8-fold 5 minutes after administration.
The pharmacokinetics of Diclofenac following intravenous administration of Diclofenac and oral doses of immediate-release Diclofenac are compared in Table 3.
Table 3: Single-dose and Multiple-dose Pharmacokinetics of Diclofenac (Diclofenac) Injection and
Oral Immediate Release (IR) Diclofenac Potassium
Figure 2: Pain Intensity Score Versus Time
References
- DailyMed. "DICLOFENAC EPOLAMINE: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
- NCIt. "Diclofenac: NCI Thesaurus (NCIt) provides reference terminology for many systems. It covers vocabulary for clinical care, translational and basic research, and public information and administrative activities.". https://ncit.nci.nih.gov/ncitbrowser... (accessed September 17, 2018).
- EPA DSStox. "Diclofenac: DSSTox provides a high quality public chemistry resource for supporting improved predictive toxicology.". https://comptox.epa.gov/dashboard/ds... (accessed September 17, 2018).
Reviews
The results of a survey conducted on ndrugs.com for Diclofenac are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Diclofenac. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.User reports
3 consumers reported administration
When best can I take Diclofenac, on an empty stomach, before or after food?ndrugs.com website users have also released a report stating that Diclofenac should be taken Empty stomach. In any case, this may not be the right description on how you ought to take this Diclofenac. Kindly visit your doctor for more medical advice in this regard. Click here to see other users view on when best the Diclofenac can be taken.
| Users | % | ||
|---|---|---|---|
| Empty stomach | 2 | 66.7% | |
| After food | 1 | 33.3% | |
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Information checked by Dr. Sachin Kumar, MD Pharmacology
