Drug Detail:Lofena (Diclofenac [ dye-kloe-fen-ak ])
Drug Class: Nonsteroidal anti-inflammatory drugs
Lofena - Clinical Pharmacology
Pharmacokinetics
Absorption
Diclofenac is 100% absorbed after oral administration compared to IV administration as measured by urine recovery. However, due to first pass metabolism, only about 50% of the absorbed dose is systemically available (see Table 1). In some fasting volunteers, measurable plasma levels are observed within 10 minutes of dosing with LOFENA. Peak plasma levels are achieved approximately 1 hour in fasting normal volunteers, with a range of .33 to 2 hours. Food has no significant effect on the extent of diclofenac absorption. However, there is usually a delay in the onset of absorption and a reduction in peak plasma levels of approximately 30%.
PK Parameter | Normal Healthy Adults (20-52 years) | |
---|---|---|
Mean | Coefficient of Variation (%) | |
Absolute Bioavailability (%) [N = 7] | 55 | 40 |
Tmax (hr)[N = 65] | 1.0 | 76 |
Oral Clearance (CL/F; mL/min) [N = 61] | 622 | 21 |
Renal Clearance (% unchanged drug in urine) [N = 7] | < 1 | - |
Apparent Volume of Distribution (V/F; L/kg) [N = 61] | 1.3 | 33 |
Terminal Half-life (hr) [N = 48] | 1.9 | 29 |
Contraindications
LOFENA™ is contraindicated in the following patients:
- Known hypersensitivity (e.g., anaphylactic reactions and serious skin reactions) to diclofenac or any components of the drug product (see WARNINGS: Anaphylactic Reactions, Serious Skin Reactions).
- History of asthma, urticaria, or allergic type reactions after taking aspirin or other NSAIDs. Severe, sometimes fatal, anaphylactic reactions to NSAIDs have been reported in such patients (see WARNINGS: Anaphylactic Reactions, Exacerbation of Asthma Related to Aspirin Sensitivity).
- In the setting of coronary artery bypass graft (CABG) surgery (see WARNINGS: Cardiovascular Thrombotic Events).
Warnings
Cardiovascular Thrombotic Events
Clinical trials of several COX-2 selective and nonselective NSAIDs of up to three years duration have shown an increased risk of serious cardiovascular (CV) thrombotic events, including myocardial infarction (MI) and stroke, which can be fatal. Based on available data, it is unclear that the risk for CV thrombotic events is similar for all NSAIDs. The relative increase in serious CV thrombotic events over baseline conferred by NSAID use appears to be similar in those with and without known CV disease or risk factors for CV disease. However, patients with known CV disease or risk factors had a higher absolute incidence of excess serious CV thrombotic events, due to their increased baseline rate. Some observational studies found that this increased risk of serious CV thrombotic events began as early as the first weeks of treatment. The increase in CV thrombotic risk has been observed most consistently at higher doses.
To minimize the potential risk for an adverse CV event in NSAID treated patients, use the lowest effective dose for the shortest duration possible. Physicians and patients should remain alert for the development of such events, throughout the entire treatment course, even in the absence of previous CV symptoms. Patients should be informed about the symptoms of serious CV events and the steps to take if they occur.
There is no consistent evidence that concurrent use of aspirin mitigates the increased risk of serious CV thrombotic events associated with NSAID use. The concurrent use of aspirin and an NSAID, such as diclofenac, increases the risk of serious gastrointestinal (GI) events (see WARNINGS: Gastrointestinal Bleeding, Ulceration, and Perforation).
Gastrointestinal Bleeding, Ulceration, and Perforation
NSAIDs, including diclofenac, cause serious gastrointestinal (GI) adverse events including inflammation, bleeding, ulceration, and perforation of the esophagus, stomach, small intestine, or large intestine, which can be fatal. These serious adverse events can occur at any time, with or without warning symptoms, in patients treated with NSAIDs. Only one in five patients, who develop a serious upper GI adverse event on NSAID therapy, is symptomatic. Upper GI ulcers, gross bleeding or perforation caused by NSAIDs occurred in approximately 1% of patients treated for 3-6 months, and in about 2%-4% of patients treated for one year. However, even short-term therapy is not without risk.
Hepatotoxicity
In clinical trials of diclofenac-containing products, meaningful elevations (i.e., more than 3 times the ULN) of AST (SGOT) were observed in about 2% of approximately 5,700 patients at some time during diclofenac treatment (ALT was not measured in all studies).
In a large, open-label, controlled trial of 3,700 patients treated with oral diclofenac sodium for 2-6 months, patients were monitored first at 8 weeks and 1,200 patients were monitored again at 24 weeks. Meaningful elevations of ALT and/or AST occurred in about 4% of patients and included marked elevations (greater than 8 times the ULN) in about 1% of the 3,700 patients. In that open-label study, a higher incidence of borderline (less than 3 times the ULN), moderate (3-8 times the ULN), and marked (greater than 8 times the ULN) elevations of ALT or AST was observed in patients receiving diclofenac when compared to other NSAIDs. Elevations in transaminases were seen more frequently in patients with osteoarthritis than in those with rheumatoid arthritis.
Almost all meaningful elevations in transaminases were detected before patients became symptomatic. Abnormal tests occurred during the first 2 months of therapy with diclofenac in 42 of the 51 patients in all trials who developed marked transaminase elevations.
In postmarketing reports, cases of drug-induced hepatotoxicity have been reported in the first month, and in some cases, the first 2 months of therapy, but can occur at any time during treatment with diclofenac. Postmarketing surveillance has reported cases of severe hepatic reactions, including liver necrosis, jaundice, fulminant hepatitis with and without jaundice, and liver failure. Some of these reported cases resulted in fatalities or liver transplantation.
In a European retrospective population-based, case-controlled study, 10 cases of diclofenac associated drug-induced liver injury with current use compared with nonuse of diclofenac were associated with a statistically significant 4-fold adjusted odds ratio of liver injury. In this particular study, based on an overall number of 10 cases of liver injury associated with diclofenac, the adjusted odds ratio increased further with female gender, doses of 150 mg or more, and duration of use for more than 90 days.
Physicians should measure transaminases at baseline and periodically in patients receiving long-term therapy with diclofenac, because severe hepatotoxicity may develop without a prodrome of distinguishing symptoms. The optimum times for making the first and subsequent transaminase measurements are not known. Based on clinical trial data and postmarketing experiences, transaminases should be monitored within 4 to 8 weeks after initiating treatment with diclofenac. However, severe hepatic reactions can occur at any time during treatment with diclofenac.
If abnormal liver tests persist or worsen, if clinical signs and/or symptoms consistent with liver disease develop, or if systemic manifestations occur (e.g., eosinophilia, rash, abdominal pain, diarrhea, dark urine, etc.), LOFENA should be discontinued immediately.
Inform patients of the warning signs and symptoms of hepatotoxicity (e.g., nausea, fatigue, lethargy, diarrhea, pruritus, jaundice, right upper quadrant tenderness, and "flu-like" symptoms). If clinical signs and symptoms consistent with liver disease develop, or if systemic manifestations occur (e.g., eosinophilia, rash, etc.), discontinue LOFENA immediately, and perform a clinical evaluation of the patient.
To minimize the potential risk for an adverse liver related event in patients treated with LOFENA use the lowest effective dose for the shortest duration possible. Exercise caution when prescribing LOFENA with concomitant drugs that are known to be potentially hepatotoxic (e.g., acetaminophen, antibiotics, anti-epileptics).
Hypertension
NSAIDs, including LOFENA can lead to new onset of hypertension or worsening of preexisting hypertension, either of which may contribute to the increased incidence of CV events.
Patients taking angiotensin converting enzyme (ACE) inhibitors, thiazides diuretics or loop diuretics may have impaired response to these therapies when taking NSAIDs (see PRECAUTIONS: Drug Interactions).
Monitor blood pressure (BP) during the initiation of NSAID treatment and throughout the course of therapy.
Heart Failure and Edema
The Coxib and traditional NSAID Trialists' Collaboration meta-analysis of randomized controlled trials demonstrated an approximately two-fold increase in hospitalization for heart failure in COX-2 selective-treated patients and nonselective NSAID treated patients compared to placebo- treated patients. In a Danish National Registry study of patients with heart failure, NSAID use increased the risk of MI, hospitalization for heart failure, and death.
Additionally, fluid retention and edema have been observed in some patients treated with NSAIDs. Use of diclofenac may blunt the CV effects of several therapeutic agents used to treat these medical conditions (e.g., diuretics, ACE inhibitors, or angiotensin receptor blockers [ARBs]) (see PRECAUTIONS: Drug Interactions).
Avoid the use of LOFENA in patients with severe heart failure unless the benefits are expected to outweigh the risk of worsening heart failure. If LOFENA is used in patients with severe heart failure, monitor patients for signs of worsening heart failure.
Renal Toxicity and Hyperkalemia
Renal Toxicity
Long-term administration of NSAIDs has resulted in renal papillary necrosis and other renal injury.
Renal toxicity has also been seen in patients in whom renal prostaglandins have a compensatory role in the maintenance of renal perfusion. In these patients, administration of an NSAID may cause a dose-dependent reduction in prostaglandin formation and, secondarily, in renal blood flow, which may precipitate overt renal decompensation. Patients at greatest risk of this reaction are those with impaired renal function, dehydration, hypovolemia, heart failure, liver dysfunction, those taking diuretics and ACE inhibitors or ARBs, and the elderly. Discontinuation of NSAID therapy is usually followed by recovery to the pretreatment state.
No information is available from controlled clinical studies regarding the use of LOFENA patients with advanced renal disease. The renal effects of LOFENA may hasten the progression of renal dysfunction in patients with preexisting renal disease.
Correct volume status in dehydrated or hypovolemic patients prior to initiating diclofenac potassium tablets. Monitor renal function in patients with renal or hepatic impairment, heart failure, dehydration, or hypovolemia during use of diclofenac potassium tablets (see PRECAUTIONS: Drug Interactions).
Avoid the use of diclofenac potassium tablets in patients with advanced renal disease unless the benefits are expected to outweigh the risk of worsening renal function. If diclofenac potassium tablets are used in patients with advanced renal disease, monitor patients for signs of worsening renal function.
Anaphylactic Reactions
Diclofenac has been associated with anaphylactic reactions in patients with and without known hypersensitivity to diclofenac and in patients with aspirin-sensitive asthma (see CONTRAINDICATIONS, WARNINGS: Exacerbation of Asthma Related to Aspirin Sensitivity).
Exacerbation of Asthma Related to Aspirin Sensitivity
A subpopulation of patients with asthma may have aspirin-sensitive asthma which may include chronic rhinosinusitis complicated by nasal polyps; severe, potentially fatal bronchospasm; and/or intolerance to aspirin and other NSAIDs. Because cross-reactivity between aspirin and other NSAIDs has been reported in such aspirin-sensitive patients, LOFENA is contraindicated in patients with this form of aspirin sensitivity (see CONTRAINDICATIONS). When LOFENA is used in patients with preexisting asthma (without known aspirin sensitivity), monitor patients for changes in the signs and symptoms of asthma.
Serious Skin Reactions
NSAIDs, including diclofenac, can cause serious skin adverse events such as exfoliative dermatitis, Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN), which can be fatal. These serious events may occur without warning. Inform patients about the signs and symptoms of serious skin reactions and discontinue the use of LOFENA at the first appearance of skin rash or any other sign of hypersensitivity. LOFENA is contraindicated in patients with previous serious skin reactions to NSAIDs (see CONTRAINDICATIONS).
Hematological Toxicity
Anemia has occurred in NSAID-treated patients. This may be due to occult or gross blood loss, fluid retention, or an incompletely described effect upon erythropoiesis. If a patient treated with LOFENA have any signs or symptoms of anemia, monitor hemoglobin or hematocrit.
NSAIDs, including LOFENA, may increase the risk of bleeding events. Co-morbid conditions such as coagulation disorders, concomitant use of warfarin and other anticoagulants, antiplatelet agents (e.g., aspirin), serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) may increase this risk. Monitor these patients for signs of bleeding (see PRECAUTIONS: Drug Interactions).
Precautions
Information for Patients
Advise the patient to read the FDA-approved patient labeling (Medication Guide) that accompanies each prescription dispensed. Inform patients, families, or their caregivers of the following information before initiating therapy with LOFENA and periodically during the course of ongoing therapy.
Cardiovascular Thrombotic Events
Advise patients to be alert for the symptoms of cardiovascular thrombotic events, including chest pain, shortness of breath, weakness, or slurring of speech, and to report any of these symptoms to their healthcare provider immediately (see WARNINGS: Cardiovascular Thrombotic Events).
Gastrointestinal Bleeding, Ulceration, and Perforation
Advise patients to report symptoms of ulcerations and bleeding, including epigastric pain, dyspepsia, melena, and hematemesis to their healthcare provider. In the setting of concomitant use of low-dose aspirin for cardiac prophylaxis, inform patients of the increased risk for the signs and symptoms of GI bleeding (see WARNINGS: Gastrointestinal Bleeding, Ulceration, and Perforation).
Laboratory Monitoring
Because serious GI bleeding, hepatotoxicity, and renal injury can occur without warning symptoms or signs, consider monitoring patients on long-term NSAID treatment with a CBC and a chemistry profile periodically (see WARNINGS: Gastrointestinal Bleeding, Ulceration and Perforation, and Hepatotoxicity).
Drug Interactions
See Table 2 for clinically significant drug interactions with diclofenac.
Drugs That Interfere with Hemostasis | |
Clinical Impact: |
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Intervention: | Monitor patients with concomitant use of LOFENA with anticoagulants (e.g., warfarin), antiplatelet agents (e.g., aspirin), selective serotonin reuptake inhibitors (SSRIs), and serotonin norepinephrine reuptake inhibitors (SNRIs) for signs of bleeding (see WARNINGS: Hematological Toxicity). |
Aspirin | |
Clinical Impact: | Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone (see WARNINGS: Gastrointestinal Bleeding, Ulceration, and Perforation). |
Intervention: | Concomitant use of LOFENA and analgesic doses of aspirin is not generally recommended because of the increased risk of bleeding (see WARNINGS: Hematological Toxicity). LOFENA is not a substitute for low dose aspirin for cardiovascular protection. |
ACE Inhibitors, Angiotensin Receptor Blockers, and Beta-Blockers | |
Clinical Impact: |
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Intervention: |
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Diuretics | |
Clinical Impact: | Clinical studies, as well as postmarketing observations, showed that NSAIDs reduced the natriuretic effect of loop diuretics (e.g., furosemide) and thiazide diuretics in some patients. This effect has been attributed to the NSAID inhibition of renal prostaglandin synthesis. |
Intervention: | During concomitant use of LOFENA with diuretics, observe patients for signs of worsening renal function, in addition to assuring diuretic efficacy including antihypertensive effects (see WARNINGS: Renal Toxicity and Hyperkalemia). |
Digoxin | |
Clinical Impact: | The concomitant use of diclofenac with digoxin has been reported to increase the serum concentration and prolong the half-life of digoxin. |
Intervention: | During concomitant use of LOFENA and digoxin, monitor serum digoxin levels. |
Lithium | |
Clinical Impact: | NSAIDs have produced elevations in plasma lithium levels and reductions in renal lithium clearance. The mean minimum lithium concentration increased 15%, and the renal clearance decreased by approximately 20%. This effect has been attributed to NSAID inhibition of renal prostaglandin synthesis. |
Intervention: | During concomitant use of LOFENA and lithium, monitor patients for signs of lithium toxicity. |
Methotrexate | |
Clinical Impact: | Concomitant use of NSAIDs and methotrexate may increase the risk for methotrexate toxicity (e.g., neutropenia, thrombocytopenia, renal dysfunction). |
Intervention: | During concomitant use of LOFENA and methotrexate, monitor patients for methotrexate toxicity. |
Cyclosporine | |
Clinical Impact: | Concomitant use of diclofenac potassium tablets and cyclosporine may increase cyclosporine's nephrotoxicity. |
Intervention: | During concomitant use of diclofenac potassium tablets and cyclosporine, monitor patients for signs of worsening renal function. |
NSAIDs and Salicylates | |
Clinical Impact: | Concomitant use of diclofenac with other NSAIDs or salicylates (e.g., diflunisal, salsalate) increases the risk of GI toxicity, with little or no increase in efficacy (see WARNINGS: Gastrointestinal Bleeding, Ulceration, and Perforation). |
Intervention: | The concomitant use of diclofenac with other NSAIDs or salicylates is not recommended. |
Pemetrexed | |
Clinical Impact: | Concomitant use of LOFENA and pemetrexed may increase the risk of pemetrexed associated myelosuppression, renal, and GI toxicity (see the pemetrexed prescribing information). |
Intervention: | During concomitant use of LOFENA and pemetrexed, in patients with renal impairment whose creatinine clearance ranges from 45 mL/min to 79 mL/min, monitor for myelosuppression, renal and GI toxicity. NSAIDs with short elimination half-lives (e.g., diclofenac, indomethacin) should be avoided for a period of two days before, the day of, and two days following administration of pemetrexed. In the absence of data regarding potential interaction between pemetrexed and NSAIDs with longer half-lives (e.g., meloxicam, nabumetone), patients taking these NSAIDs should interrupt dosing for at least five days before, the day of, and two days following pemetrexed administration. |
CYP2C9 Inhibitors or Inducers | |
Clinical Impact: | Diclofenac is metabolized by cytochrome P450 enzymes, predominantly by CYP2C9. Co-administration of diclofenac with CYP2C9 inhibitors (e.g., voriconazole) may enhance the exposure and toxicity of diclofenac whereas co-administration with CYP2C9 inducers (e.g., rifampin) may lead to compromised efficacy of diclofenac. |
Intervention: | A dosage adjustment may be warranted when diclofenac is administered with CYP2C9 inhibitors or inducers (see CLINICAL PHARMACOLOGY: Pharmacokinetics). |
Adverse Reactions/Side Effects
The following adverse reactions are discussed in greater detail in other sections of the labeling:
- Cardiovascular Thrombotic Events (see WARNINGS)
- GI Bleeding, Ulceration and Perforation (see WARNINGS)
- Hepatotoxicity (see WARNINGS)
- Hypertension (see WARNINGS)
- Heart Failure and Edema (see WARNINGS)
- Renal Toxicity and Hyperkalemia (see WARNINGS)
- Anaphylactic Reactions (see WARNINGS)
- Serious Skin Reactions (see WARNINGS)
- Hematologic Toxicity (see WARNINGS)
LOFENA
diclofenac potassium tablet, film coated |
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Labeler - CARWIN PHARMACEUTICAL ASSOCIATES, LLC (079217215) |