K-Fenak contains diclofenac potassium 50 mg, an anti-inflammatory painkiller. It is used for pain and inflammation — headache, period pain, backache, dental pain, muscular aches, sprains and arthritis. It is sold in both a pharmacy-only form and a stronger-scheduled anti-inflammatory form.
What is K Fenak?
K-Fenak contains diclofenac potassium 50 mg and is registered in South Africa in more than one form:
| Product | Contains | Schedule |
|---|---|---|
| K-Fenak OTC | Diclofenac potassium 50 mg | S2 |
| K-Fenak Anti-Inflammatory | Diclofenac potassium 50 mg | S3 |
The tablets contain the same amount of the same medicine. The difference is in how they are supplied and what they are intended for: the S2 version is for short-term self-limiting pain, obtained from a pharmacist; the S3 version is intended for use under closer guidance, typically for inflammatory conditions over a longer period. If you are unsure which you have, check the pack.
Diclofenac is a non-steroidal anti-inflammatory drug (NSAID). It blocks cyclo-oxygenase (COX) enzymes, which the body uses to make prostaglandins — the messengers behind inflammation, swelling, pain signalling and fever. Reducing them relieves all four.
The “potassium” part is about speed, not strength. Diclofenac comes as either a potassium or a sodium salt. The potassium form dissolves and absorbs faster, so it acts sooner — which suits acute pain such as a headache or period pain. The sodium form is often used in slower-release tablets for steady control of an ongoing condition. The active medicine is diclofenac either way.
Diclofenac is one of the more potent commonly used anti-inflammatories. It is also, among the widely used NSAIDs, one of the more significant for cardiovascular risk, which is why it is not the automatic first choice for everyone.
What is K Fenak commonly used for?
- Headache and migraine, where the fast-absorbing potassium salt is useful.
- Period pain, often more effective than a simple painkiller.
- Backache and muscular pain.
- Sprains, strains and sports injury, where swelling is part of the problem.
- Dental pain, as short-term relief while awaiting treatment.
- Joint pain, including osteoarthritis and rheumatoid arthritis flares.
- Gout flares.
- Pain after minor surgery or injury.
- Fever, though it is not usually the first choice for that alone.
The difference from paracetamol is worth understanding. Paracetamol eases pain and fever but does little for inflammation, and is gentle on the stomach, kidneys and heart. Diclofenac genuinely reduces inflammation and swelling — but carries cautions paracetamol does not.
Use the lowest effective dose for the shortest time that works. With NSAIDs this is not routine caution: most of the harm rises with dose and duration, so a two-day course carries far less risk than months of daily use.
How K Fenak fits into this medicine category
| Group | Examples | What it does |
|---|---|---|
| Simple analgesics | Paracetamol (Panado, Donapan) | Pain and fever; minimal anti-inflammatory effect |
| Non-selective NSAIDs | Diclofenac (K-Fenak), ibuprofen | Pain and inflammation; stomach, kidney, heart cautions |
| COX-2 selective | Celecoxib, etoricoxib | Anti-inflammatory, gentler on the stomach |
| Topical NSAIDs | Diclofenac gel | Local joint and muscle pain, far less systemic effect |
| Corticosteroids | Prednisone | Powerful anti-inflammatory, given as courses |
| Compound analgesics | Mybulen, Stilpane | Paracetamol with codeine and others |
For localised pain in a joint or muscle close to the surface, a topical diclofenac gel gives useful relief with much less systemic exposure — often a sensible option for people who should avoid oral NSAIDs. See the general medicines hub and the pain and inflammation hub.
What to check before using K Fenak
Do not take it with another anti-inflammatory. Ibuprofen, naproxen, mefenamic acid and aspirin are all NSAIDs. Combining them multiplies the risk of stomach bleeding without improving pain relief — and these ingredients hide in combination cold, flu and period-pain products, so read the labels.
Speak to a pharmacist or doctor first if you:
- Have had a stomach ulcer, gastritis or bleeding in the gut.
- Have heart disease, heart failure, high blood pressure, or a history of heart attack or stroke. Diclofenac carries a higher cardiovascular risk than some alternatives, and is generally avoided in established heart disease.
- Have kidney disease, or are dehydrated.
- Have liver disease.
- Have asthma. A minority of people with asthma wheeze significantly on NSAIDs.
- Are over 65.
- Are pregnant. NSAIDs are generally avoided, particularly from around 20 weeks and definitely in the third trimester.
- Are breastfeeding.
- Take warfarin or another blood thinner.
- Take an ACE inhibitor or ARB with a diuretic — that combination plus an NSAID is a recognised cause of acute kidney injury.
- Take low-dose aspirin for your heart, lithium, methotrexate, or an SSRI antidepressant.
Take it with food or after eating, follow the pack instructions, and do not continue longer than advised. This page does not set doses.
Possible cautions and when to ask a pharmacist or doctor
Common effects are indigestion, nausea, abdominal discomfort, headache, dizziness and diarrhoea. Taking it with food helps the stomach symptoms.
Stop and seek medical attention urgently if you notice:
- Vomiting blood, or vomit resembling coffee grounds.
- Black, tarry stools.
- Severe stomach pain.
- Chest pain, breathlessness, or sudden weakness or slurred speech on one side — seek emergency care.
- Swelling of the face, lips or tongue, or difficulty breathing.
- Sudden wheezing, particularly with asthma.
- A spreading rash, blistering or peeling skin.
- Yellowing of the eyes or skin.
- Much less urine than usual, or swollen ankles.
Serious stomach bleeding can develop without warning pain first, which is why the bleeding signs matter even when you otherwise feel well.
See a doctor if pain lasts more than a few days, if it worsens, if fever persists past three days, or if you find yourself needing an anti-inflammatory most days. Continuous use is a reason to establish the cause rather than keep suppressing the symptom.
Related medicine guides
Frequently asked questions
What are K-Fenak tablets used for? Pain and inflammation — headache, period pain, backache, dental pain, muscular aches, sprains, and arthritis flares. Each tablet contains diclofenac potassium 50 mg.
What is the difference between K-Fenak and K-Fenak OTC? Both contain diclofenac potassium 50 mg. They differ in scheduling and intended use: the OTC version is a pharmacy medicine for short-term pain, the anti-inflammatory version is supplied under closer guidance.
Is K-Fenak a painkiller or an anti-inflammatory? Both. As an NSAID it relieves pain and reduces inflammation and swelling.
Is it stronger than ibuprofen? Diclofenac is generally regarded as a more potent anti-inflammatory, but it also carries a somewhat higher cardiovascular risk. Which suits you depends on your health.
Can I take it with paracetamol? They are different medicines and are sometimes used together on advice. Do not combine it with another anti-inflammatory.
Can I take it on an empty stomach? Better with food. Diclofenac can irritate the stomach lining.
Is it safe in pregnancy? Generally avoided, especially from around 20 weeks. Paracetamol is usually preferred — confirm with your doctor or pharmacist.
How long can I take it for? For the shortest time that controls the problem. Extended use should be a decision made with a doctor.