Naproxen Tablets 500mg
1.
NAME OF THE MEDICINAL PRODUCT
Naproxen 500mg Tablets
2 QUALITATIVE AND QUANTITATIVE COMPOSITION
Each tablet contains 500mg Naproxen BP
Excipients with known effect: Also contains 98.979 mg of lactose and 0.027 mg of sunset yellow (E110)
For the full list of excipients, see section 6.1
3 PHARMACEUTICAL FORM
Tablet.
Pale yellow, oblong tablets with N breakline 500 on one side and BL on the other
4. CLINICAL PARTICULARS
4.1. Therapeutic indications
Adults
Naproxen is indicated for the treatment of rheumatoid arthritis, osteoarthrosis (degenerative arthritis), ankylosing spondylitis, acute gout, acute musculoskeletal disorders and dysmenorrhoea.
Children
Juvenile rheumatoid arthritis
4.2 Posology and method of administration
Posology
Undesirable effects may be minimised by using the lowest effective dose for the shortest duration necessary to control symptoms (see section 4.4).
Adults
Rheumatoid arthritis, osteoarthritis and ankylosing spondylitis
The usual dose is 500mg to 1g per day taken in two doses at 12-hour intervals or alternatively, as a single administration. The size of the morning and evening doses can be adjusted on the basis of the predominant symptoms (ie night time pain or morning stiffness).
As a single administration of two tablets, morning or evening, in the following cases a loading dose of 750mg -1g per day for the acute phase is recommended:
1. In patients reporting severe night-time pain and / or morning stiffness.
2. In patients being switched to naproxen from a high dose of another antirheumatic compound.
3. In osteoarthrosis where pain is the predominant symptom.
Acute gout
The recommended dosage is 750mg at once then 250mg every eight hours until the attack has passed.
Acute musculoskeletal disorders and dysmenorrhoea
The recommended dosage is 500mg initially followed by 250mg at 6 to 8 hour intervals as needed, with a maximum of 1250mg daily after the first day.
Elderly
Studies indicate that although total plasma concentration of naproxen is unchanged, the unbound plasma fraction of naproxen is increased in the elderly. The implication of this finding for naproxen dosing is unknown. As with other drugs used in the elderly it is prudent to use the lowest effective dose and for the shortest duration possible as elderly patients are more prone to adverse events. The patient should be monitored regularly for GI bleeding during NSAID therapy. For the effect of reduced elimination in the elderly refer to Section 4.4.
Children (over 5 years)
For juvenile rheumatoid arthritis: 10mg/kg/day taken in 2 doses at 12-hour intervals. Naproxen is not recommended for use in any other indication in children under 16 years of age.
Renal/hepatic impairment
A lower dose should be considered in patients with renal or hepatic impairment. Naproxen is contraindicated in patients with baseline creatinine clearance less than 30 ml/minute because accumulation of naproxen metabolites has been seen in patients with severe renal failure or those on dialysis (see section 4.3).
Treatment should be reviewed at regular intervals and discontinued if no benefit is seen or intolerance occurs.
Method of administration
For oral administration.
To be taken preferably with or after food.
4.3 Contraindications
• Hypersensitivity to naproxen, naproxen sodium, or to any of the excipients listed in section 6.1
• Active or history of recurrent peptic ulcer/haemorrhage (two or more distinct episodes of proven ulceration or bleeding).
• History of gastrointestinal bleeding or perforation, related to previous NSAIDs therapy.
• Since the potential exists for cross-sensitivity reactions, naproxen should not be given to patients in whom aspirin or other non-steroidal anti-inflammatory/analgesic drugs induce the syndrome of asthma, rhinitis, nasal polyps, angioedema or urticaria. These reactions have the potential of being fatal. Severe anaphylactic-like reactions to naproxen have been reported in such patients.
• Severe heart failure, hepatic failure and renal failure (see section 4.4)
• During the third trimester of pregnancy (see section 4.6)
4.4 Special warnings and precautions for use
Undesirable effects may be minimised by using the lowest effective dose for the shortest duration necessary to control symptoms (see section 4.2, and GI and cardiovascular risks below).
Patients treated with NSAIDs long-term should undergo regular medical supervision to monitor for adverse events.
Elderly and/or debilitated patients
Elderly and/or debilitated patients are particularly susceptible to the adverse effects of NSAIDs, especially gastrointestinal bleeding and perforation, which may be fatal (see section 4.2). Prolonged use of NSAIDs in these patients is not recommended. Where prolonged therapy is required, patients should be reviewed regularly.
Respiratory disorders
Bronchospasm may be precipitated in patients suffering from, or with a history of, bronchial asthma or allergic disease.
Gastrointestinal bleeding, ulceration and perforation
GI bleeding, ulceration or perforation, which can be fatal, has been reported with all NSAIDs at any time during treatment, with or without warning symptoms or a previous history of serious GI events.
The risk of GI bleeding, ulceration or perforation is higher with increasing NSAID doses, in patients with a history of ulcer, particularly if complicated with haemorrhage or perforation (see section 4.3), in the elderly, when used with alcohol and in smoking.
These patients should commence treatment on the lowest dose available. Combination therapy with protective agents (e.g. misoprostol or proton pump inhibitors) should be considered for these patients, and also for patients requiring concomitant low dose aspirin, or other drugs likely to increase gastrointestinal risk (see below and section 4.5).
Patients with a history of GI toxicity, particularly when elderly, should report any unusual abdominal symptoms (especially GI bleeding) particularly in the initial stages of treatment.
Caution should be advised in patients receiving concomitant medications which could increase the risk of ulceration or bleeding, such as oral corticosteroids, anticoagulants such as warfarin, selective serotonin-reuptake inhibitors or anti-platelet agents such as aspirin (see section 4.5).
When GI bleeding or ulceration occurs in patients receiving naproxen, the treatment should be withdrawn.
NSAIDs should be given with care to patients with a history of gastrointestinal disease (ulcerative colitis, Crohn's disease) as these conditions may be exacerbated (see section 4.8).
Renal Effects
There have been reports of impaired renal function, renal failure, acute interstitial nephritis, haematuria, proteinuria, renal papillary necrosis and occasionally nephrotic syndrome associated with naproxen.
Cardiovascular, Renal and Hepatic Impairment
The administration of an NSAID may cause a dose dependent reduction in prostaglandin formation and precipitate renal failure. Patients at greatest risk of this reaction are those with impaired renal function, cardiac impairment, liver dysfunction, those taking diuretics, angiotensin converting enzyme inhibitors, angiotensin II receptor antagonists and the elderly. Renal function should be monitored in these patients (see also section 4.3).
Use in patients with impaired renal function
As naproxen is eliminated to a large extent (95%) by urinary excretion via glomerular filtration, it should be used with great caution in patients with impaired renal function and the monitoring of serum creatinine and/or creatinine clearance is advised and
patients should be adequately hydrated. Naproxen is contraindicated in patients having a baseline creatinine clearance of less than 20ml/minute.
Haemodialysis does not decrease the plasma concentration of naproxen because of the high degree of protein binding.
Certain patients, specifically those whose renal blood flow is compromised, such as in extracellular volume depletion, cirrhosis of the liver, sodium restriction, congestive heart failure, and pre-existing renal disease, should have renal function assessed before and during naproxen therapy. Some elderly patients in whom impaired renal function may be expected, as well as patients using diuretics, may also fall within this category. A reduction in daily dosage should be considered to avoid the possibility of excessive accumulation of naproxen metabolites in these patients.
Use in patients with impaired liver function
Chronic alcoholic liver disease and probably also other forms of cirrhosis reduce the total plasma concentration of naproxen, but the plasma concentration of unbound naproxen is increased. The implication of this finding for naproxen dosing is unknown but it is prudent to use the lowest effective dose. The product should be used with caution in patients with a history of, or in those with impaired liver function.
Haematological
Naproxen, in common with other NSAIDs, decreases platelet aggregation and prolongs bleeding time. This effect should be kept in mind when bleeding times are determined. Patients who have coagulation disorders or who are receiving drug therapy that affects haemostasis should be carefully observed when given naproxen (see section 4.5). Patients on full anticoagulant therapy (eg heparin or warfarin) may be at an increased risk of bleeding if given naproxen concurrently. Therefore, the benefits should be weighed against these risks.
Anaphylactic (anaphylactoid) reactions
Hypersensitivity reactions may occur in susceptible individuals. Anaphylactic (anaphylactoid) reactions may occur both in patients with and without a history of hypersensitivity or exposure to aspirin, other non-steroidal anti-inflammatory drugs or naproxen-containing products. They may also occur in individuals with a history of angio-oedema, bronchospastic reactivity (e.g. asthma), rhinitis and nasal polyps.
Anaphylactoid reactions, like anaphylaxis, may have a fatal outcome.
Oedema
Mild peripheral oedema has been observed in a few patients receiving naproxen. Although sodium retention has not been reported in metabolic studies, it is possible that patients with questionable or compromised function may be at a greater risk when taking naproxen.
Steroids
If steroid dosage is reduced or eliminated during therapy, the steroid dosage should be reduced slowly and the patients must be observed closely for any evidence of adverse effects, including adrenal insufficiency and exacerbation of symptoms of arthritis.
Ocular effects
Studies have not shown changes in the eye attributable to naproxen administration. In rare cases, adverse ocular disorders including papillitis, retrobulbar optic neuritis and papilloedema, have been reported in users of NSAIDs including naproxen, although a cause-and-effect relationship cannot be established; accordingly, patients who develop visual disturbances during treatment with naproxen-containing products should have an ophthalmological examination.
Cardiovascular and cerebrovascular effects
Appropriate monitoring and advice are-required for patients with a history of hypertension and/or mild to moderate congestive heart failure as fluid retention and oedema have been reported in association with NSAID therapy. Clinical trial and epidemiological data suggest that use of coxibs and some NSAIDs (particularly at high doses and in long term treatment) may be associated with a small increased risk of arterial thrombotic events (for example myocardial infarction or stroke). Although data suggest that the use of naproxen (1000 mg daily) may be associated with a lower risk, some risk cannot be excluded.
Patients with uncontrolled hypertension, congestive heart failure, established ischaemic heart disease, peripheral arterial disease, and/or cerebrovascular disease should only be treated with naproxen after careful consideration. Similar consideration should be made before initiating longer-term treatment of patients with risk factors for cardiovascular events (e.g. hypertension, hyperlipidaemia, diabetes mellitus, smoking).
SLE and mixed connective tissue disease
In patients with systemic lupus erythematosus (SLE) and mixed connective tissue disorders there may be an increased risk of aseptic meningitis (see section 4.8).
Dermatological
Serious skin reactions, some of them fatal, including exfoliative dermatitis, Stevens-Johnson syndrome, and toxic epidermal necrolysis, have been reported very rarely in association with the use of NSAIDs (see section 4.8). Patients appear to be at highest risk for these reactions early in the course of therapy: the onset of the reaction occurring in the majority of cases within the first month of treatment. Naproxen should be discontinued at the first appearance of skin rash, mucosal lesions, or any other sign of hypersensitivity.
Precautions related to fertility
The use of Naproxen as with any drug known to inhibit cyclooxygenase/prostaglandin synthesis, may impair female fertility and is not recommended in women attempting to conceive. In women who have difficulties conceiving or who are undergoing investigation of infertility, withdrawal of Naproxen should be considered.
Combination with other NSAIDs
The combination of naproxen-containing products and other NSAIDs, including cyclooxygenase-2 selective inhibitors, is not recommended, because of the cumulative risks of inducing serious NSAID-related adverse events.
The use of Naproxen with concomitant NSAIDs including cyclooxygenase-2 selective inhibitors should be avoided (see section 4.5).
The antipyretic and anti-inflammatory activities of naproxen may reduce fever and inflammation thereby diminishing their utility as diagnostic signs
Interference in tests
Naproxen therapy should be temporarily withdrawn 48 hours before adrenal function tests are performed as it may artifactually interfere with some tests for 17-ketogenic steroids. Similarly, naproxen may interfere with some assays of urinary 5-hydroxyindoleacetic acid.
Sporadic abnormalities in laboratory tests (e.g. liver function test) have occurred in patients on naproxen therapy, but no definite trend was seen in any test indicating toxicity.
Medication Overuse Headache (MOH)
After long term treatment with analgesics, headache may develop or aggravate. Headache caused by overuse of analgesics (MOH - medication-overuse headache) should be suspected in patients who have frequent or daily headaches despite (or because of) regular use of analgesics. Patients with medication overuse headache should not be treated by increasing the dose. In such cases the use of analgesics should be discontinued in consultation with a doctor.
Important information regarding the ingredients of this medicine This medicinal product contains Lactose. Patients with rare hereditary problems of galactose intolerance, the Lapp lactose deficiency or glucose-galactose malabsorption should not take this medicine.
Naproxen Tablets also contain Sunset yellow, which may cause allergic reactions.
4.5 Interaction with other medicinal products and other forms of interaction
Colestyramine
Concomitant administration of antacid or colestyramine can delay the absorption of naproxen but does not affect its extent. Naproxen should be taken at least one hour before or four to six hours after colestyramine.
Anti-coagulants
It is considered unsafe to take NSAIDs in combination with anti-coagulants such as warfarin or heparin unless under direct medical supervision, as NSAIDs may enhance the effects of anti-coagulants (see Section 4.4).
Due to the high plasma protein binding of naproxen, patients simultaneously receiving hydantoins, anticoagulants or a highly protein-bound sulphonamide should be observed for signs of overdosage of these drugs. Patients simultaneously receiving Naproxen and a hydantoin, sulphonamide or sulphonylurea should be observed for adjustment of dose if required. No interactions have been observed in clinical studies with naproxen and anticoagulants or sulphonylureas, but caution is nevertheless advised since interaction has been seen with other non-steroidal agents of this class.
Lithium
NSAIDs, including naproxen, have been reported to increase steady state plasma lithium levels by inhibition of renal lithium clearance. Decreased elimination of lithium. It is recommended that these levels are monitored whenever initiating, adjusting or discontinuing naproxen.
Probenecid
Probenecid given concurrently increases naproxen plasma levels and extends its plasma half-life considerably.
Methotrexate
Caution is advised where methotrexate is administered concurrently because of possible enhancement of its toxicity, since naproxen, among other nonsteroidal antiinflammatory drugs decreases the elimination of methotrexate.
Diuretics
NSAIDs may reduce the effect of diuretics and antihypertensive medicinal products. The risk of acute renal insufficiency, which is usually reversible, may be increased in some patients with compromised renal function (e.g. dehydrated patients or elderly patients) when angiotensin II receptor antagonists are combined with NSAIDs. Therefore, the combination should be administered with caution, especially in the elderly. Patients should be adequately hydrated and consideration should be given to monitoring of renal function after initiation of concomitant therapy, and periodically thereafter. Diuretics can increase the risk of nephrotoxicity of NSAIDs. The natriuretic effect of furosemide has been reported to be inhibited by some drugs of this class.
Other analgesics including cyclooxygenase-2 selective inhibitors
Avoid concomitant use of two or more NSAIDs (including aspirin) as this may increase
the risk of adverse effects (see section 4.4).
Anti-hypertensives
Naproxen and other non-steroidal anti-inflammatory drugs can reduce the antihypertensive effect of anti-hypertensives. Concomitant use of NSAIDs with ACE inhibitors or angiotensin-II receptor antagonists may increase the risk of renal impairment, especially in patients with pre-existing poor renal function (see section 4.4).
Cardiac glycosides
NSAIDs may exacerbate cardiac failure, reduce GFR and increase plasma glycoside levels when co-administered with cardiac glycosides.
Ciclosporin
As with all NSAIDs caution is advised when ciclosporin is co-administered because of the increased risk of nephrotoxicity.
Mifepristone
NSAIDs should not be used for 8-12 days after mifepristone administration as NSAIDs can reduce the effect of mifepristone.
Cortisosteroids
As with all NSAIDs, caution should be taken when co-administering with corticosteroids because of the increased risk of gastrointestinal ulceration or bleeding.
Quinolone antibiotics
Animal data indicate that NSAIDs can increase the risk of convulsions associated with quinolone antibiotics. Patients taking NSAIDs and quinolones may have an increased risk of developing convulsions.
Anti-platelet agents and selective serotonin reuptake inhibitors (SSRls)
There is an increased risk of gastrointestinal bleeding (see Section 4.4) when antiplatelet agents and selective serotonin reuptake inhibitors (SSRIs) are combined with NSAIDs.
Tacrolimus
Possible increased risk of nephrotoxicity when NSAIDs are given with tacrolimus. Zidovudine
Increased risk of haematological toxicity when NSAIDs are given with zidovudine. There is evidence of an increased risk of haemarthroses and haematoma in HIV(+) haemophiliacs receiving concurrent treatment with zidovudine and ibuprofen.
Bisphosphonates
Concomitant use of bisphosphonates and NSAIDs may increase the risk of gastric mucosal damage.
4.6 Fertility, Pregnancy and Lactation
Pregnancy
Inhibition of prostaglandin synthesis may adversely affect the pregnancy and/or the embryo/foetal development. Data from epidemiological studies suggest an increased risk of miscarriage and of cardiac malformation after use of a prostaglandin synthesis inhibitor in early pregnancy. The absolute risk for cardiovascular malformation was increased from less than 1%, up to approximately 1.5%. The risk is believed to increase with dose and duration of therapy. In animals, administration of a prostaglandin synthesis inhibitor has been shown to result in increased pre- and post- implantation loss and embryo-foetal lethality. In addition, increased incidences of various malformations, including cardiovascular, have been reported in animals given a prostaglandin synthesis inhibitor during the organogenetic period. During the first and second trimester of pregnancy, naproxen should not be given unless clearly necessary.
If naproxen is used by a woman attempting to conceive, or during the first and second trimester of pregnancy, the dose should be kept as low and duration of treatment as short as possible.
During the third trimester of pregnancy, all prostaglandin synthesis inhibitors may expose the foetus to:
- cardiopulmonary toxicity (with premature closure of the ductus arteriosus and pulmonary hypertension);
- renal dysfunction, which may progress to renal failure with oligo-hydramniosis; the mother and the neonate, at the end of pregnancy to:
- possible prolongation of bleeding time, an anti-aggregating effect which may occur even at very low doses.
- inhibition of uterine contractions resulting in delayed or prolonged labour. Consequently naproxen is contraindicated during the last trimester of pregnancy.
Lactation
In limited studies so far available, NSAIDs can appear in breast milk in very low concentrations. NSAIDs should, if possible, be avoided when breastfeeding. See section 4.4 for use regarding female fertility.
4.7 Effects on ability to drive and use machines
Some patients may experience drowsiness, dizziness, vertigo, insomnia, fatigue, visual disturbances or depression with the use of Naproxen. If patients experience these or similar undesirable effects, they should not drive or operate machinery.
4.8 Undesirable effects
The following adverse events have been reported with NSAIDs and with naproxen. Gastrointestin al
The most commonly-observed adverse events are gastrointestinal in nature.
Peptic ulcers, perforation or GI bleeding, sometimes fatal, particularly in the elderly, may occur (See section 4.4). Nausea, vomiting, diarrhoea, flatulence, constipation,
dyspepsia, abdominal pain, melaena, haematemesis, ulcerative stomatitis, exacerbation of colitis and Crohn's disease (See section 4.4) have been reported following administration. Less frequently, gastritis has been observed.
Oedema, hypertension and cardiac failure have been reported in association with NSAID treatment.
|
System Organ Class |
Common (> 1/100 < 1/10) |
Uncommon (> 1/1000 < 1/100) |
Rare (> 1/10,000 < 1/1000) |
Very Rare (< 1/10,00) |
Frequency not known (cannot be estimated from the available data) |
|
Blood and lymphatic system disorders |
haemolytic anaemia |
granulo- cyctopenia, thrombo cytopenia, agranulocytosis |
aplastic anaemia, neutropenia | ||
|
Immune system disorders |
allergic and hypersensitivity reactions, anaphylaxis | ||||
|
Metabolism and nutrition disorders |
hyperkalaemia | ||||
|
Psychiatric disorders |
depression, cognitive dysfunction, insomnia, loss of concentration, abnormal dreams |
hallucinations | |||
|
Nervous system disorders |
confusion, dizziness, drowsiness, headache |
convulsions, aseptic meningitis* |
vertigo, paraesthesia, malaise, exacerbation of Parkinson's disease | ||
|
Eye disorders |
visual disturbances |
optic neuritis, papilloedema | |||
|
Ear and labyrinth disorders |
tinnitus |
hearing impairment |
|
Cardiac disorders |
palpitations | ||||
|
Vascular disorders |
vasculitis |
arterial thrombotic events e.g. myocardial infarction or stroke(see 4.4) | |||
|
Respiratory, thoracic and mediastinal disorders |
aggravated asthma, eosinophilic pneumontitis |
bronchospasm, dyspnoea, rhinitis, pulmonary oedema | |||
|
Gastro intestinal disorders |
pancreatitis |
thirst | |||
|
Hepatobiliary |
hepatitis (sometimes fatal), jaundice |
abnormal liver function, | |||
|
Skin and subcutaneous tissue disorders |
rash, pruritis, purpura |
urticaria, photosensitivity |
alopecia, pseudo porphyria |
erythema multiforme, Stevens Johnsons syndrome, toxic epidermal necrosis, epidermolysis bullosa |
angio-oedema, epidermal necrosis, exfoliative and bullous dermatoses, lichen planus |
|
Musculoskeletal and connective tissue disorders |
myalgia, muscle weakness | ||||
|
Renal and urinary disorders |
glomerular nephritis, haematuria, interstitial nephritis, nephritic syndrome, renal papillary necrosis |
renal failure, nephropathy, increase in serum creatinine | |||
|
Reproductive system and breast |
impaired female fertility (see 4.4) |
|
disorders | |||||
|
General disorders and administration site complications |
fatigue |
mild peripheral oedema, pyrexia | |||
|
*especiall |
y in patients wit |
i existing auto-immune disorders, such as systemic lupus | |||
erythematosus, mixed connective tissue disease, with symptoms such as stiff neck headache, nausea, vomiting, fever and disorientation.
Clinical trial and epidemiological data suggests that use of some NSAIDs (particularly at high doses and in long term treatment) may be associated with an increased risk of arterial thrombotic events (for example myocardial infarction or stroke (see section 4.4).
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme website: www.mhra.gov.uk/yellowcard.
4.9 Overdose
Symptoms
Symptoms include headache, heartburn, nausea, vomiting, epigastric pain, gastrointestinal bleeding, rarely diarrhoea, disorientation, excitation, coma, drowsiness, dizziness, tinnitus, fainting, occasionally convulsions. In cases of significant poisoning acute renal failure and liver damage are possible.
Respiratory depression may occur after the ingestion of NSAIDs but are rare.
In one case of naproxen overdose, transient prolongation of the prothrombin time due to hypothrombinaemia may have been due to selective inhibition of the synthesis of vitamin-K dependent clotting factors.
In cases of significant poisoning acute renal failure and liver damage are possible. It is not known what dose of the drug would be life-threatening.
Management
Patients should be treated symptomatically as required. Within one hour of ingestion of a potentially toxic amount activated charcoal should be considered. Alternatively in adults gastric lavage should be considered within one hour of ingestion of a potentially life-threatening overdose.
Good urine output should be ensured.
Renal and liver function should be closely monitored.
Patients should be observed for at least four hours after ingestion of potentially toxic amounts.
Frequent or prolonged convulsions should be treated with intravenous diazepam.
Other measures may be indicated by the patient's clinical condition.
Haemodialysis does not decrease the plasma concentration of naproxen because of the high degree of protein binding. However, haemodialysis may still be appropriate in a patient with renal failure who has taken naproxen.
5 PHARMACOLOGICAL PROPERTIES
5.1 Pharmacodynamic properties
Naproxen is a non-steroidal anti-inflammatory analgesic compound. Naproxen reduces the synthesis of prostaglandins primarily by inhibiting the enzyme cyclo-oxygenase. Naproxen has been shown to have anti-inflammatory activity in a number of experimental models. Naproxen inhibits prostaglandin E2 synthesis in vitro by human rheumatoid synovial microsomes. It also inhibits prostaglandin E2 production by phytohaemagglutin-stimulated peripheral blood mononuclear cells. At 10-4 M (23mg.1-1) naproxen inhibits neutral protease activity derived from human polymorphonuclear leucocytes. Naproxen also inhibits in vitro the activity of cathepsin-P and other hydrolytic enzymes derived from lysosomes. Naproxen is a potent in inhibitor of leucocyte migration and produces effects comparable to those of colchicine.
5.2 Pharmacokinetic properties
Naproxen is completely absorbed from the gastro-intestinal tract, and peak plasma levels are reached in 2 to 4 hours. Naproxen is present in the blood mainly as unchanged drug, extensively bound to plasma proteins. The plasma half-life is between 12 and 15 hours, enabling a steady state to be achieved within 3 days of initiation of therapy on a twice daily dose regimen. The degree of absorption is not significantly affected by either foods or most antacids. Excretion is almost entirely via the urine, mainly as conjugated naproxen, with some unchanged drug. Metabolism in children is similar to that in adults. Approximately 95% of a dose is excreted in urine as naproxen and 6-O-desmethylnaproxen and their conjugates. Less than 3% of a dose has been recovered in the faeces. Naproxen crosses the placenta and is excreted in breast milk.
Chronic alcoholic liver disease reduces the total plasma concentration of naproxen but the concentration of unbound naproxen increases. In the elderly, the unbound plasma concentration of naproxen is increased although total plasma concentration is unchanged.
5.3 Preclinical safety data
Carcinogenicity
Naproxen was administered with food to Sprague-Dawley rats for 24 months at doses of 8, 16 and 24mg/kg/day. Naproxen was not carcinogenic in rats.
Mutagenicity
Mutagenicity was not seen in Salmonella typhimurium (5 cell lines), Sachharomyces cerevisisae (1 cell line), and mouse lymphoma tests.
Fertility
Naproxen did not affect the fertility of rats when administered orally at doses of 30mg/kg/day to males and 20mg/kg/day to females.
Teratogenicity
Naproxen was not teratogenic when administered orally at doses of 20mg/kg/day during organogenesis to rats and rabbits.
Perinatal/Postnatal Reproduction
Oral administration of naproxen to pregnant rats at doses of 2, 10 and 20mg/kg/day during the third trimester of pregnancy resulted in difficult labour. These are known effects of this class of compounds and were demonstrated in pregnant rats with aspirin and indometacin.
PHARMACEUTICAL PARTICULARS
6
6.1 List of excipients
Sodium lauryl sulphate, lactose, quinoline yellow E104, sunset yellow E110, maize starch, crospovidone, magnesium stearate.
6.2 Incompatibilities
None known.
6.3 Shelf life
3 years.
6.4 Special precautions for storage
Store in a cool dry place.
Protect from light. Do not store above 25°C
6.5 Nature and contents of container
1. Polypropylene tubes fitted with low-density polyethylene caps.
2. Tracer Packs: Child resistant containers consisting of polypropylene tubes fitted with high density polyethylene caps.
Pack sizes: 28, 56, 100 and 500 tablets.
3. PVC/Aluminium
Pack sizes : 28,56,84 and 112 tablets .
6.6 Special precautions for disposal
None stated.
7 MARKETING AUTHORISATION HOLDER
Bristol Laboratories Limited
Unit 3, Canalside, Northbridge road
Berkhamsted
Herts
HP4 1EG
UK
8 MARKETING AUTHORISATION NUMBER(S)
PL 17907/0340
9 DATE OF FIRST AUTHORISATION/RENEWAL OF THE
AUTHORISATION
22 April 2002
10 DATE OF REVISION OF THE TEXT
25/05/2016