1. Clinical Overview
A fixed-dose combination (FDC) analgesic-antispasmodic agent primarily used for the symptomatic relief of pain and spasms associated with dysmenorrhea, abdominal colic, and other smooth muscle spasms. Dicyclomine is an anticholinergic/antispasmodic, Paracetamol is a centrally-acting analgesic/antipyretic, and Mefenamic Acid is a peripherally-acting NSAID (Propionic acid derivative). This combination provides a multi-modal approach to pain management, targeting both visceral spasm and pain pathways.
| Onset | Duration | Bioavailability |
|---|---|---|
| Dicyclomine: 1-2 hours (oral); Paracetamol: 30-60 minutes; Mefenamic Acid: 30-60 minutes. | Dicyclomine: 4-6 hours; Paracetamol: 4-6 hours; Mefenamic Acid: 4-6 hours. | Dicyclomine: ~67% (oral); Paracetamol: ~88% (oral); Mefenamic Acid: ~90% (oral). |
2. Mechanism of Action
The combination exerts a synergistic effect on pain relief. Dicyclomine acts as a competitive muscarinic acetylcholine receptor antagonist, reducing smooth muscle tone and motility in the gastrointestinal and genitourinary tracts, thereby relieving spasm. Paracetamol's exact mechanism is not fully elucidated but is believed to involve central inhibition of prostaglandin synthesis (COX-2 and COX-3 inhibition) and modulation of serotonergic and cannabinoid pathways, providing analgesic and antipyretic effects. Mefenamic Acid is a non-selective cyclooxygenase (COX-1 and COX-2) inhibitor, reducing the peripheral synthesis of prostaglandins, which are key mediators of pain, inflammation, and fever.
3. Indications & Uses
- Primary dysmenorrhea (menstrual cramps)
- Abdominal colic and pain associated with smooth muscle spasm (e.g., intestinal colic, biliary colic)
- Pain associated with urogenital tract spasm
4. Dosage & Administration
Adult Dosage: One tablet every 6-8 hours, as required for pain. The total daily dose should not exceed 3 tablets (i.e., Dicyclomine 30mg, Paracetamol 1500mg, Mefenamic Acid 750mg). Should be taken after food with a full glass of water.
Administration: Take after meals or with food/milk to minimize gastrointestinal irritation. Swallow whole with a full glass of water. Do not crush or chew. Do not lie down for at least 10 minutes after taking the tablet. Use for the shortest duration necessary to control symptoms.
5. Side Effects
Common side effects may include:
- Nausea
- Dry mouth
- Dizziness
- Drowsiness
- Constipation
- Heartburn/Epigastric discomfort
- Headache
- Blurred vision (mild)
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Warfarin/Acenocoumarol | Increased risk of bleeding due to protein binding displacement and antiplatelet effect of Mefenamic Acid. | Major |
| Lithium | Mefenamic Acid can decrease renal clearance of Lithium, leading to toxicity. | Major |
| Methotrexate | Mefenamic Acid may reduce renal excretion of Methotrexate, increasing toxicity risk. | Major |
| Other NSAIDs (e.g., Ibuprofen, Aspirin) | Increased risk of GI ulcers/bleeding and renal toxicity (additive effects). | Major |
| Anticholinergics (e.g., Atropine, Tricyclic Antidepressants) | Additive anticholinergic side effects (dry mouth, constipation, urinary retention, confusion). | Moderate |
| Antihypertensives (ACE inhibitors, ARBs, Diuretics) | Mefenamic Acid can reduce the antihypertensive efficacy and impair renal function. | Moderate |
| Corticosteroids (e.g., Prednisolone) | Markedly increased risk of GI ulceration. | Major |
| Selective Serotonin Reuptake Inhibitors (SSRIs) | Increased risk of upper GI bleeding. | Moderate |
| Antiepileptics (e.g., Phenobarbital, Carbamazepine) | Increased metabolism of Paracetamol to toxic NAPQI, increasing hepatotoxicity risk. | Moderate |
| Alcohol | Chronic use increases risk of GI bleeding and Paracetamol-induced hepatotoxicity. | Major |
| Cholestyramine | Reduces absorption of Mefenamic Acid. | Moderate |
| Probenecid | May increase Mefenamic Acid levels by reducing its excretion. | Moderate |
7. Patient Counselling
- DO take after food with a full glass of water.
- DO use the lowest effective dose for the shortest time needed.
- DO inform your doctor if you are pregnant, planning pregnancy, or breastfeeding.
- DO inform your doctor about all other medicines you are taking, including OTC and herbal products.
- DONT take more than the prescribed dose or for longer than directed.
- DONT crush, chew, or break the tablet.
- DONT take with other products containing Paracetamol or NSAIDs (like Ibuprofen).
- DONT lie down immediately after taking the medicine.
- DONT consume alcohol while on this medication.
8. Toxicology & Storage
Overdose: Dicyclomine: Anticholinergic crisis (flushed skin, hyperthermia, tachycardia, dilated pupils, urinary retention, ileus, delirium, seizures). Paracetamol: Stage 1 (0-24h): Nausea, vomiting, malaise. Stage 2 (24-72h): Right upper quadrant pain, elevated LFTs. Stage 3 (72-96h): Peak hepatotoxicity (jaundice, coagulopathy, encephalopathy). Stage 4 (4d-2w): Recovery or fatal liver failure. Mefenamic Acid: Nausea, vomiting, abdominal pain, GI bleeding, headache, dizziness, tinnitus, seizures, acute renal failure, metabolic acidosis.
Storage: Store below 30°C, in a cool, dry place. Protect from light and moisture. Keep out of reach of children. Do not use after the expiry date printed on the pack.