1. Clinical Overview
Aceclofenac (100mg) + Paracetamol (325mg) is a widely prescribed, fixed-dose combination analgesic and anti-inflammatory medication in India. Aceclofenac is a potent non-steroidal anti-inflammatory drug (NSAID) of the phenylacetic acid class, providing anti-inflammatory, analgesic, and antipyretic effects primarily through COX-2 inhibition. Paracetamol (Acetaminophen) is a centrally-acting analgesic and antipyretic with weak peripheral anti-inflammatory activity. This combination offers synergistic pain relief, allowing for lower effective doses of the NSAID component, potentially reducing the risk of dose-dependent gastrointestinal and renal side effects associated with NSAID monotherapy. It is a mainstay for managing acute painful inflammatory conditions.
| Onset | Duration | Bioavailability |
|---|---|---|
| Analgesic effect begins within 30-60 minutes. | Approximately 6-8 hours. | Aceclofenac: Nearly 100%. Paracetamol: 85-98%. |
2. Mechanism of Action
The combination provides analgesia through complementary mechanisms. Aceclofenac inhibits the cyclooxygenase (COX) enzymes, preferentially COX-2, thereby reducing the synthesis of prostaglandins (PGs), thromboxanes, and prostacyclins from arachidonic acid at the site of inflammation. This reduces inflammation, pain, and fever. Paracetamol's exact mechanism is not fully elucidated but is believed to act centrally by inhibiting prostaglandin synthesis in the brain (likely via inhibition of a COX-2 variant, COX-3) and modulating the descending serotonergic pathways and cannabinoid systems, providing analgesia and antipyresis with minimal peripheral anti-inflammatory effect.
3. Indications & Uses
- Osteoarthritis
- Rheumatoid Arthritis
- Ankylosing Spondylitis
- Acute Musculoskeletal Pain (e.g., low back pain, sprains)
4. Dosage & Administration
Adult Dosage: One tablet (Aceclofenac 100mg + Paracetamol 325mg) twice daily, preferably after food. The maximum recommended duration for self-medication of acute pain is 3 days; use beyond this should be under medical supervision.
Administration: Take with or immediately after a meal or a glass of milk to minimize gastric irritation. Swallow the tablet whole with a full glass of water. Do not crush or chew. Do not lie down for at least 10 minutes after taking the dose.
5. Side Effects
Common side effects may include:
- Nausea
- Dyspepsia (indigestion)
- Abdominal pain
- Diarrhea or Constipation
- Headache
- Dizziness
- Skin rash or itching
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Warfarin, Acenocoumarol | Increased risk of bleeding due to antiplatelet effect of Aceclofenac and displacement from protein binding. | Major |
| Aspirin, other NSAIDs | Increased risk of GI toxicity (ulcers, bleeding) with no added therapeutic benefit. | Major |
| Methotrexate | Aceclofenac may reduce renal clearance of Methotrexate, increasing its toxicity (myelosuppression). | Major |
| Lithium | Aceclofenac may decrease renal clearance of Lithium, leading to increased serum levels and toxicity. | Major |
| Diuretics (Furosemide, Thiazides) | NSAIDs may reduce the diuretic and antihypertensive effect and increase risk of renal impairment. | Moderate |
| ACE Inhibitors (Ramipril) / ARBs (Losartan) | Reduced antihypertensive effect; increased risk of renal impairment, especially in volume-depleted patients. | Moderate |
| Ciclosporin, Tacrolimus | Increased risk of nephrotoxicity. | Major |
| Antidiabetics (Sulfonylureas) | Aceclofenac may potentiate hypoglycemic effect. | Moderate |
| Cholestyramine | Reduces absorption of Paracetamol if taken within 1 hour. | Moderate |
| Enzyme Inducers (Rifampicin, Phenytoin, Carbamazepine, Alcohol chronic) | Increased metabolism of Paracetamol to NAPQI, raising hepatotoxicity risk. | Major |
| Isoniazid | May increase risk of Paracetamol hepatotoxicity. | Moderate |
| Probenecid | May increase Aceclofenac levels by reducing its renal clearance. | Moderate |
7. Patient Counselling
- DO take with food or milk to reduce stomach upset.
- DO inform your doctor about all other medicines you are taking, including OTC vitamins and herbal products.
- DO stay well-hydrated while on this medication.
- DO use the lowest effective dose for the shortest time needed.
- DONT take more than the prescribed dose or for longer than directed.
- DONT crush, break, or chew the tablet.
- DONT take other products containing Paracetamol (cold, flu, headache remedies) concurrently.
- DONT consume alcohol while on this medication.
- DONT use for fever for more than 3 days or for pain for more than 5-10 days unless directed by a doctor.
8. Toxicology & Storage
Overdose: Aceclofenac Overdose: Nausea, vomiting, epigastric pain, GI bleeding, dizziness, tinnitus, seizures, acute renal failure, respiratory depression, coma. Paracetamol Overdose: Stage 1 (0-24h): Nausea, vomiting, anorexia, malaise. Stage 2 (24-72h): Right upper quadrant pain, elevated liver enzymes. Stage 3 (72-96h): Peak hepatotoxicity (jaundice, coagulopathy, encephalopathy), potentially fatal hepatic necrosis. Stage 4 (4d-2wks): Recovery.
Storage: Store below 30°C, in a cool, dry place, protected from light and moisture. Keep out of reach of children. Do not use after the expiry date printed on the pack.