Ketoprofen-sf
Poland
Table of Contents
Package leaflet: Information for the patient
Ketoprofen-SF, 50 mg, hard capsules
Ketoprofen-SF, 100 mg, hard capsules
Ketoprofenum
Please read this leaflet carefully before taking this medicine, because it contains
important information for the patient.
- Keep this leaflet, as you may need to read it again.
- If you have any questions, please consult your doctor or pharmacist.
- This medicine has been prescribed for a specific individual. Do not pass it on to others. This medicine may harm others, even if their symptoms are the same.
- If you experience any adverse reactions, including any adverse reactions not listed in this leaflet, inform your doctor or pharmacist. See section 4.
Table of contents of the leaflet
- What Ketoprofen-SF is and what it is used for
- Important information before taking Ketoprofen-SF
- How to take Ketoprofen-SF
- Possible side effects
- How to store Ketoprofen-SF
- Contents of the pack and other information
1. What Ketoprofen-SF is and what it is used for
Ketoprofen-SF is used for symptomatic treatment of pain and inflammation in the following conditions:
- Acute arthritis,
- Chronic arthritis, especially rheumatoid arthritis (chronic polyarthritis),
- Ankylosing spondylitis (Bechterew's disease) and other rheumatic inflammatory conditions of the spine,
- Exacerbation of osteoarthritis and spinal osteoarthritis (degenerative joint disease).
2. Important information before using Ketoprofen-SF
When not to use Ketoprofen-SF:
- if the patient is allergic to ketoprofen or any of the other ingredients of this medicine (listed in section 6),
- if the patient has ever experienced bronchospasm, asthma attack, nasal mucosal swelling (rhinitis), skin reactions (urticaria) or other allergic reactions after taking ketoprofen, acetylsalicylic acid or other nonsteroidal anti-inflammatory drugs (NSAIDs). Anaphylactic reactions, which may be severe and rarely fatal, have been reported in such patients (see section 4),
- if the patient has previously experienced skin hypersensitivity reactions to light (photoallergic or phototoxic reactions) during treatment with ketoprofen or fibrates (medicines that lower blood lipid levels),
- if the patient has unexplained disorders of the blood-forming system (the system responsible for blood component production),
- if the patient has active gastrointestinal ulcer (peptic ulcer of the stomach and/or duodenum) or a history of gastrointestinal bleeding, ulceration or perforation,
- if the patient has a bleeding tendency,
- if the patient has bleeding into the brain (cerebral haemorrhage) or other active bleeding,
- if the patient has severe heart failure,
- if the patient has severe liver or kidney function disorders,
- during the last three months of pregnancy.
Warnings and precautions
Before starting treatment with Ketoprofen-SF, discuss this with your doctor or pharmacist.
Inform your pharmacist or doctor if the patient has an infection – see below, section titled "Infections".
The section "Warnings and precautions" contains information on when the patient may take Ketoprofen-SF only under certain conditions (i.e. with longer intervals between doses or lower doses, with simultaneous monitoring of organ function). However, even in such cases, special caution is required. For further information, please consult your doctor.
This section also applies to patients who have previously experienced the situations described below.
Taking the medicine at the lowest effective dose for the shortest duration necessary to relieve symptoms reduces the risk of adverse effects.
Effects on the gastrointestinal tract (stomach and intestines)
Avoid concomitant use of Ketoprofen-SF with other NSAIDs (nonsteroidal anti-inflammatory drugs), including so-called selective cyclooxygenase-2 inhibitors.
Elderly patients
When using NSAIDs, the risk of adverse effects, particularly gastrointestinal bleeding or perforation, which may be fatal, is higher in elderly patients. For this reason, elderly patients require special medical care.
Gastrointestinal bleeding, ulcers and perforations
Gastrointestinal bleeding, ulceration or perforation, which may be fatal, have been reported with all NSAIDs, at any time during treatment, with or without warning symptoms or serious gastrointestinal events in history.
Epidemiological data indicate that ketoprofen use may be associated with increased gastrointestinal toxicity compared to other NSAIDs, especially when higher doses are used.
The risk of gastrointestinal bleeding, ulceration or perforation increases with higher NSAID doses, in patients with a history of peptic ulcer disease, particularly if complicated by bleeding or perforation (see section 2 "When not to use Ketoprofen-SF"), and in elderly patients. Therefore, treatment in elderly patients should be initiated with the lowest available dose.
Consideration should be given to co-therapy with protective agents (e.g. misoprostol or proton pump inhibitors) in these patients, as well as in patients requiring concomitant treatment with low-dose acetylsalicylic acid and other medicines increasing the risk of gastrointestinal adverse effects.
Patients, especially elderly ones, should report any unusual abdominal symptoms (particularly gastrointestinal bleeding), especially at the beginning of treatment.
Caution is advised in patients taking concomitant medications that may increase the risk of ulcers or bleeding, such as oral corticosteroids, anticoagulants (blood thinners) such as warfarin, selective serotonin reuptake inhibitors (used, among others, in depression treatment), or antiplatelet agents such as acetylsalicylic acid (see section "Ketoprofen-SF and other medicines").
If gastrointestinal ulceration or bleeding occurs, Ketoprofen-SF should be discontinued immediately.
NSAIDs should be used with caution in patients with a history of gastrointestinal disorders (ulcerative colitis, Crohn's disease), as these medicines may exacerbate these conditions (see section 4 "Possible adverse effects").
Effects on the circulatory and cerebral vascular system
Taking medicines such as Ketoprofen-SF may be associated with a small increased risk of heart attack (myocardial infarction) or stroke. The risk is higher with long-term use of high doses. Do not use higher doses or longer treatment duration than recommended.
If the patient has heart problems, has had a stroke, or is suspected of having risk factors for these conditions (e.g. high blood pressure, diabetes, high cholesterol, smoking), discuss the treatment approach with your doctor or pharmacist.
Caution is advised in patients with hypertension and/or mild to moderate heart failure in history, as fluid retention and oedema have been reported with NSAID treatment.
Skin reactions
Very rare cases of serious, sometimes fatal skin reactions – with redness and blisters – have been reported during NSAID treatment (including Stevens-Johnson syndrome, toxic epidermal necrolysis (Lyell's syndrome); see section 4 "Possible adverse effects"). The risk of these reactions is probably higher at the beginning of treatment, as most cases occurred within the first month of therapy. At the first signs of skin rash, mucosal changes or other symptoms of hypersensitivity, Ketoprofen-SF should be discontinued immediately and medical advice sought.
Photoallergic reactions caused by NSAIDs are well-known adverse effects of this group of medicines and are most commonly attributed to UV radiation. Ketoprofen increases the risk of photoallergic contact dermatitis. Symptoms may sometimes appear only after a latency period of sensitization. Skin symptoms may persist for several months after discontinuation of the drug. If a photoallergic reaction occurs in patients taking Ketoprofen-SF, treatment should be discontinued and medical advice sought.
Infections
Ketoprofen-SF may mask objective signs of infection, such as fever and pain. Therefore, Ketoprofen-SF may delay appropriate treatment of infection and consequently increase the risk of complications. This has been observed in bacterial pneumonia and bacterial skin infections associated with chickenpox. If the patient is taking this medicine during an existing infection and symptoms persist or worsen, medical advice should be sought immediately.
Other information
Ketoprofen-SF should be used only after careful consideration of benefit-risk ratio in specific congenital disorders of blood cell production (porphyria).
At the beginning of treatment in patients with heart failure, liver cirrhosis, nephrotic syndrome, patients receiving diuretics, and patients with chronic kidney failure, especially elderly patients, kidney function should be carefully monitored. In such patients, ketoprofen administration may cause reduced renal blood flow due to inhibition of prostaglandin synthesis, leading to kidney function disorders.
Close medical supervision is required in the following cases:
- in patients with pre-existing kidney damage,
- in patients with liver function disorders,
- in patients immediately after major surgery,
- in patients with allergies (e.g. skin reactions to other medicines, asthma, hay fever), chronic rhinitis, chronic respiratory diseases with airway constriction,
- in patients taking potent diuretics,
- in patients taking NSAIDs or other painkillers,
- in patients with blood clotting disorders and those taking anticoagulant medicines.
Acute hypersensitivity reactions (e.g. anaphylactic shock) are very rare.
If the first signs of severe hypersensitivity reactions occur after taking Ketoprofen-SF, the medicine should be discontinued. Depending on symptoms, any medical intervention must be performed by a specialist.
If visual disturbances occur, such as blurred vision, treatment should be discontinued.
Ketoprofen, the active substance in Ketoprofen-SF, may temporarily inhibit platelet aggregation. Patients with blood clotting disorders should be closely monitored.
If anticoagulant (blood-thinning) medicines or blood glucose-lowering medicines are used concomitantly with ketoprofen, blood glucose and coagulation should be carefully monitored.
Like other NSAIDs, ketoprofen may mask signs of infectious diseases.
In patients with abnormal liver function test results or a history of liver disease, aminotransferase levels should be periodically checked, especially during long-term treatment.
Rare cases of jaundice and hepatitis associated with ketoprofen use have been reported.
During prolonged treatment with Ketoprofen-SF, regular monitoring of liver enzyme activity, kidney function and blood morphology is required.
Inform your doctor or dentist about taking Ketoprofen-SF before undergoing surgery.
Patients with asthma combined with chronic rhinitis, chronic sinusitis and/or nasal polyps have a higher risk of allergy to acetylsalicylic acid and/or NSAIDs than the general population. Taking this medicine may provoke asthma attacks or bronchospasm, especially in patients allergic to acetylsalicylic acid or NSAIDs (see section 2 "When not to use Ketoprofen-SF").
Prolonged use of painkillers may lead to headache, which should not be treated by increasing the dose of the medicine. If frequent headaches occur despite treatment with Ketoprofen-SF, medical advice should be sought.
Chronic use of painkillers, especially when multiple painkillers are taken simultaneously, may lead to permanent kidney damage, including kidney failure (analgesic nephropathy).
Ketoprofen-SF and other medicines
Inform your doctor or pharmacist about all medicines currently or recently taken, as well as those planned for use.
Concomitant use of Ketoprofen-SF and digoxin (used to strengthen heart muscle) may worsen heart failure and increase serum digoxin concentration. Monitoring of serum digoxin levels is recommended.
Concomitant use of Ketoprofen-SF with medicines containing phenytoin (used in epilepsy treatment) or lithium (used in psychiatric disorders treatment) may increase their serum concentrations, sometimes leading to toxic serum lithium levels due to reduced renal lithium excretion. Serum lithium concentrations should be carefully monitored, and monitoring of serum phenytoin concentration is recommended.
Ketoprofen-SF may reduce the effectiveness of diuretics (fluid-removing medicines), beta-blockers and medicines used to treat hypertension.
Ketoprofen-SF may reduce the effectiveness of angiotensin-converting enzyme inhibitors (medicines used in heart failure and hypertension treatment). Additionally, concomitant use of these medicines may increase the risk of kidney function disorders.
Concomitant use of Ketoprofen-SF and potassium-sparing diuretics (a group of diuretic medicines) may lead to increased serum potassium levels. Serum potassium levels should be monitored.
Concomitant use of Ketoprofen-SF with other NSAIDs (including selective cyclooxygenase-2 inhibitors) or glucocorticosteroids increases the risk of gastrointestinal ulcers or bleeding.
Antiplatelet agents (inhibiting or reducing blood clotting), such as acetylsalicylic acid and certain antidepressants (selective serotonin reuptake inhibitors – SSRIs), may increase the risk of gastrointestinal bleeding.
Administration of Ketoprofen-SF within 24 hours before or after methotrexate (a medicine used in cancer and autoimmune disease treatment) may lead to increased methotrexate concentration and enhance its adverse effects.
Concomitant use of Ketoprofen-SF with cyclosporine or tacrolimus may carry a risk of additive nephrotoxic effects, especially in elderly patients.
Medicines containing probenecid and sulfinpyrazone (used in gout treatment) may delay ketoprofen elimination. This may lead to excessive accumulation of Ketoprofen-SF in the body and increase the frequency and severity of adverse effects.
NSAIDs may enhance the effect of anticoagulant (blood-thinning) medicines such as warfarin.
To date, clinical studies have not shown interactions between ketoprofen and oral antidiabetic medicines (used in diabetes treatment). Nevertheless, preventive monitoring of blood glucose levels during concomitant treatment is recommended.
Concomitant use of loop diuretics (used in hypertension treatment) may increase the frequency of kidney function disorders.
Medicines that neutralize gastric juice may reduce ketoprofen absorption in the intestine.
Concomitant use of pentoxifylline (a medicine used in intermittent claudication treatment) with Ketoprofen-SF may increase the risk of bleeding.
Administration of antibiotics (medicines used to treat bacterial infectious diseases), such as quinolone derivatives, may increase the risk of seizures.
Ketoprofen-SF enhances the effect of thrombolytic medicines (medicines preventing blood clot formation).
Ketoprofen-SF and alcohol
Do not consume alcohol during treatment with Ketoprofen-SF.
Pregnancy, breastfeeding and effects on fertility
If the patient is pregnant or breastfeeding, suspects she may be pregnant, or is planning to have a child, she should consult her doctor or pharmacist before using this medicine.
Do not use Ketoprofen-SF if the patient is in the last three months of pregnancy, as it may harm the unborn child or cause problems during delivery. It may cause kidney and heart disorders in the unborn child. It may increase the tendency to bleeding in both mother and child and may delay or prolong labour.
During the first 6 months of pregnancy, Ketoprofen-SF should not be used unless the doctor considers it absolutely necessary. If treatment is required during this period or when trying to conceive, the lowest possible dose should be used for the shortest possible time. From week 20 of pregnancy, Ketoprofen-SF may cause kidney function disorders in the unborn child if used for more than a few days. This may lead to reduced amniotic fluid volume surrounding the child (oligohydramnios) or narrowing of a blood vessel (ductus arteriosus) in the child's heart. If treatment is required for longer than a few days, the doctor may recommend additional monitoring.
There are no data on ketoprofen passage into breast milk. Use of Ketoprofen-SF is not recommended in breastfeeding women.
Ketoprofen-SF may impair fertility. Inform your doctor if the patient is planning to conceive or has difficulty conceiving.
Driving and operating machinery
As adverse effects on the central nervous system (e.g. fatigue, dizziness) may occur during use of higher doses of Ketoprofen-SF, reaction ability may be delayed in individual cases, and the ability to drive or operate machinery may be impaired. This is particularly relevant when alcohol is consumed concomitantly.
Patients should be informed about the possibility of drowsiness, dizziness or seizures and advised not to drive or operate machinery if such symptoms occur.
Ketoprofen-SF contains lactose
If the patient has previously been diagnosed with intolerance to certain sugars, the patient should consult their doctor before taking this medicine.
3. How to use Ketoprofen-SF
This medicine should always be used as directed by a physician. In case of doubt, consult a
physician or pharmacist.
Adults
Use the lowest effective dose for the shortest duration necessary to relieve symptoms. If signs
of infection (such as fever and pain) persist or worsen, consult a physician immediately (see section 2).
The recommended daily dose for adults depends on the severity of the disease.
50 mg dose:
Unless otherwise prescribed, the following dosing is recommended:
The recommended daily dose is 1 – 4 capsules of Ketoprofen-SF (corresponding to 50 – 200 mg
of ketoprofen), administered in 1 – 2 single doses.
100 mg dose:
Unless otherwise prescribed, the following dosing is recommended:
The recommended daily dose is 1 – 2 capsules (corresponding to 100 – 200 mg of ketoprofen),
administered in 1 – 2 single doses.
Use in children and adolescents
Ketoprofen-SF is not recommended for use in children and adolescents due to insufficient data
on safety and efficacy in this age group.
How to take the capsules
Always use Ketoprofen-SF as directed by a physician. In case of doubt, consult a physician or
pharmacist.
Ketoprofen-SF capsules should be swallowed whole (do not chew), with a large amount of fluid,
during or after a meal.
Duration of treatment
The duration of treatment will be determined by the physician.
Use of a higher than recommended dose of Ketoprofen-SF
Symptoms of overdose may include central nervous system disturbances such as headache,
dizziness, lethargy, drowsiness, confusion, and loss of consciousness, as well as abdominal/epigastric
pain, nausea, and vomiting. Additionally, hypotension, respiratory depression (reduced respiratory
rate), and skin and mucous membrane purpura (cyanosis) may occur.
There is no specific antidote.
Inform a physician immediately if an overdose of Ketoprofen-SF is suspected. The physician will
determine appropriate preventive measures based on the severity of intoxication.
Missed dose of Ketoprofen-SF
Do not take a double dose to make up for a missed dose.
Discontinuation of Ketoprofen-SF
Inform the physician.
If you have any further doubts regarding the use of this medicine, consult a physician or pharmacist.
4. Possible adverse effects
Like all medicines, this medicine can cause adverse effects, although not everyone will experience them.
When considering the adverse effects listed for this medicine, it should be remembered that they are mainly dose-dependent and may vary between individual patients.
Adverse effects most commonly affect the gastrointestinal tract. Gastrointestinal ulceration (peptic ulcer), perforation or bleeding – sometimes with fatal outcome – may occur, particularly in elderly patients (see section 2 "Warnings and precautions"). After administration of Ketoprofen-SF, nausea, vomiting, diarrhoea, flatulence (passing wind), constipation, dyspepsia, melaena (black, tarry stools), haematemesis (vomiting blood), oral ulcerative inflammation (small ulcers or painful swellings of the oral and lingual mucosa), and worsening of colitis or Crohn's disease have been reported (see section 2 "Warnings and precautions"). Gastric mucositis has been observed less frequently. The risk of gastrointestinal bleeding particularly depends on dose and duration of treatment.
Oedema, high blood pressure and heart failure have been reported in association with treatment with NSAIDs.
Use of medicines such as Ketoprofen-SF may be associated with a small increased risk of heart attack (myocardial infarction) or stroke.
The following adverse effects have been reported with ketoprofen use in adults:
Very common (may affect more than 1 in 10 patients)
Gastrointestinal disturbances, e.g. nausea, vomiting, heartburn, stomach pain, flatulence, constipation or diarrhoea, and minor gastrointestinal bleeding, which in isolated cases may lead to anaemia.
Common (may affect up to 1 in 10 patients)
Hypersensitivity reactions such as skin rash and pruritus, insomnia, restlessness, irritability, headache, dizziness, fatigue, dyspepsia, abdominal pain, gastrointestinal ulceration with bleeding and perforation in some cases, fluid accumulation in the upper or lower limbs (peripheral oedema), particularly in patients with high blood pressure.
Uncommon (may affect up to 1 in 100 patients)
Somnolence, visual disturbances (see section 2 "Warnings and precautions"), tinnitus (ringing in the ears), haematemesis (vomiting blood), black, tarry stools (melaena), inflammation of the oral mucosa, gastritis.
If moderate to severe epigastric pain, haematemesis, blood in stool and/or black stool colouration occur, treatment with Ketoprofen-SF should be discontinued immediately and medical advice should be sought without delay.
Liver function abnormalities, photosensitivity, skin rash, pruritus, oedema, fluid retention in the body, excessive protein loss in urine (nephrotic syndrome), inflammatory changes in kidney tissue (interstitial nephritis), kidney function disturbances.
Reduced urine output, fluid accumulation in the body (oedema) and general malaise may indicate kidney dysfunction, and even kidney failure.
Rare (may affect up to 1 in 1,000 patients)
Haemorrhagic anaemia, paraesthesia, asthma, hepatitis, increased aminotransferase activity, increased serum bilirubin concentration due to liver disorders, weight gain.
Very rare (may affect up to 1 in 10,000 patients)
Cases of worsening inflammatory conditions associated with infection (e.g. necrotizing fasciitis) have been described in connection with administration of NSAIDs, including Ketoprofen-SF. Therefore, immediate medical advice should be sought if signs or symptoms of infection appear or worsen (e.g. redness, swelling, warmth, pain, fever) during treatment with Ketoprofen-SF.
Haemolytic anaemia (caused by accelerated breakdown of red blood cells), blood disorders (aplastic anaemia, leukopenia, thrombocytopenia, pancytopenia, agranulocytosis). Initial symptoms may include: fever, sore throat, superficial oral ulcers, flu-like symptoms, severe fatigue, nosebleeds and skin haemorrhages. In such cases, treatment with Ketoprofen-SF should be stopped immediately and medical advice should be sought. The above symptoms should not be treated with analgesic or antipyretic medicines.
During long-term treatment, blood counts should be monitored regularly.
Acute hypersensitivity reactions. Symptoms include: facial swelling, tongue swelling, internal swelling of the larynx with airway narrowing, dyspnoea, palpitations, decreased blood pressure, and even life-threatening anaphylactic shock.
Immediate medical advice should be sought if early signs of the above symptoms occur, which may appear even after the first dose of Ketoprofen-SF.
Heart failure, myocardial infarction, arterial hypertension, pancreatitis, intestinal stricture, liver damage (particularly during long-term treatment), hair loss (alopecia), serious skin reactions such as erythematous rash with blisters (e.g. Stevens-Johnson syndrome and toxic epidermal necrolysis – Lyell's syndrome), kidney damage (papillary necrosis), particularly during long-term treatment, and increased uric acid concentration.
After several months of uneventful use, the skin may become photosensitive, showing signs of erythema, pruritus, blistering and nodules on areas of skin exposed to sunlight or artificial UV light (e.g. sunbeds).
Frequency not known (frequency cannot be estimated from available data)
Bone marrow failure, mood changes, convulsions, taste disturbances, vasodilation, bronchospasm (particularly in patients with hypersensitivity to acetylsalicylic acid and other NSAIDs), nasal mucositis, exacerbation of colitis and Crohn's disease, urticaria, angioedema, abnormal kidney function test results, confusion, aseptic meningitis.
Kidney function should be monitored regularly.
Reporting of adverse effects
If any adverse effects occur, including any not listed in this leaflet, inform your doctor or pharmacist. Adverse effects can be reported directly to the Department of Monitoring Adverse Drug Reactions, Office for Registration of Medicinal Products, Medical Devices and Biocidal Products
Al. Jerozolimskie 181C
02-222 Warsaw
Tel.: +48 22 49 21 301
Fax: +48 22 49 21 309
Website: https://smz.ezdrowie.gov.pl
Adverse effects can also be reported to the marketing authorisation holder.
Reporting adverse effects helps to provide more information on the safety of this medicine.
5. How to store Ketoprofen-SF
Keep this medicine out of the sight and reach of children.
Do not use this medicine after the expiry date stated on the blister and the cardboard
package after: EXP. The expiry date refers to the last day of the stated month.
Ketoprofen-SF 50 mg:
Do not store above 25°C.
Ketoprofen-SF 100 mg:
Do not store above 30°C.
Medicines must not be disposed of via wastewater. Ask your pharmacist how to dispose of medicines you no longer use.
This will help protect the environment.
6. Contents of the pack and other information
What Ketoprofen-SF contains
Ketoprofen-SF 50 mg:
The active substance is ketoprofen.
Each capsule contains 50 mg of ketoprofen.
The other ingredients are:
Capsule contents:
Monohydrate lactose, magnesium stearate, colloidal anhydrous silica.
Capsule shell:
Gelatin, titanium dioxide (E171), iron oxide, black (E172), erythrosine (E127),
indigotine (E132).
Ketoprofen-SF 100 mg:
The active substance is ketoprofen.
Each capsule contains 100 mg of ketoprofen.
The other ingredients are:
Capsule contents:
Monohydrate lactose, magnesium stearate, colloidal anhydrous silica.
Capsule shell:
Gelatin, titanium dioxide (E171), iron oxide, black (E172), erythrosine (E127),
indigotine (E132), iron oxide, yellow (E172).
What Ketoprofen-SF looks like and contents of the pack
Ketoprofen-SF 50 mg:
Ketoprofen-SF is a hard gelatin capsule with an opaque blue-violet cap and a white body, filled with whitish-grey powder.
Ketoprofen-SF is available in PVC/PVDC/Aluminium blister packs containing 20, 24, 50 or 100 capsules.
Ketoprofen-SF 100 mg:
Ketoprofen-SF is a hard gelatin capsule with an opaque blue-violet cap and a yellow body, filled with whitish-grey powder.
Ketoprofen-SF is available in PVC/PVDC/Aluminium blister packs containing 20, 30, 50 or 100 capsules.
Not all pack sizes may be marketed.
Marketing Authorisation Holder and Manufacturer
Marketing Authorisation Holder
SUN-FARM Sp. z o.o.
ul. Dolna 21
05-092 Łomianki
Poland
Manufacturer
mibe GmbH Arzneimittel
Münchener Straße 15
06796 Brehna
Germany
This medicinal product is authorised in the Member States of the European Economic Area under the following names:
Ketoprofen-SF 50 mg:
Germany: Gabrilen N 50 mg
Poland: Ketoprofen-SF
Ketoprofen-SF 100 mg:
Germany: Gabrilen N 100 mg
Poland: Ketoprofen-SF