Dolonex SP

Dicyclomine (20mg) + Paracetamol (500mg) + Mefenamic Acid (250mg)
Price: ₹25 - ₹35 for strip of 10 tablets
Mfr: Macleods Pharmaceuticals Ltd. | Form: Tablet

📋 Clinical Overview

A fixed-dose combination (FDC) analgesic-antispasmodic medication primarily indicated for the symptomatic relief of moderate to severe pain associated with smooth muscle spasm, such as in dysmenorrhea, renal colic, and intestinal colic. Dicyclomine is an anticholinergic antispasmodic, Paracetamol is a centrally-acting analgesic and antipyretic, and Mefenamic Acid is a peripherally-acting NSAID with analgesic, anti-inflammatory, and antipyretic properties. This combination provides a multi-modal approach to pain relief by targeting both visceral spasm and pain pathways.

💊 Dosage & Administration

Adult: One tablet three times a day (TDS) or as directed by the physician. The total daily dose of mefenamic acid should not exceed 1500mg (i.e., 6 tablets of this FDC).

Note: Take with or after food to minimize gastrointestinal irritation. Swallow whole with a full glass of water. Do not crush or chew. Should be used for the shortest duration necessary to control symptoms.

⚠️ Contraindications

  • Hypersensitivity to dicyclomine, paracetamol, mefenamic acid, or any component
  • Patients with porphyria
  • Inflammatory bowel disease (ulcerative colitis, Crohn's) due to risk of toxic megacolon from dicyclomine
  • Severe hepatic impairment (Child-Pugh Class C)
  • Severe renal impairment (eGFR <30 mL/min)
  • History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs
  • During the third trimester of pregnancy
  • Peptic ulcer disease or active gastrointestinal bleeding

🔬 Mechanism of Action

The combination exerts a synergistic effect. Dicyclomine acts as a competitive muscarinic acetylcholine receptor antagonist, reducing smooth muscle tone and motility in the gastrointestinal and genitourinary tracts. 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. Mefenamic Acid is a reversible, competitive inhibitor of both cyclooxygenase (COX-1 and COX-2) enzymes, reducing the synthesis of prostaglandins, thromboxanes, and prostacyclins at the site of inflammation, thereby providing peripheral analgesic and anti-inflammatory effects.

🤕 Side Effects

  • Nausea
  • Dry mouth
  • Dizziness/Drowsiness
  • Constipation
  • Heartburn/Epigastric discomfort
  • Headache

🤰 Special Populations

Pregnancy: Pregnancy Category C (US FDA). Avoid, especially in the first and third trimesters. First trimester: NSAID use associated with risk of miscarriage and congenital malformations. Third trimester: Risk of premature closure of ductus arteriosus, oligohydramnios, and prolonged labor. Paracetamol is preferred if an analgesic is needed. Dicyclomine may cause fetal tachycardia. Use only if potential benefit justifies potential fetal risk.

Driving: May cause dizziness, drowsiness, or blurred vision. Patients should be cautioned about operating machinery or driving until they know how the medication affects them.

🔄 Drug Interactions

Other Anticholinergics (e.g., Atropine, Trihexyphenidyl)Additive anticholinergic side effects (dry mouth, constipation, urinary retention, confusion).Major
Oral Anticoagulants (Warfarin, Acenocoumarol)Mefenamic Acid displaces warfarin from protein binding and inhibits platelet function, increasing risk of bleeding.Major
Other NSAIDs (including Aspirin)Increased risk of GI ulceration and bleeding. Reduced antiplatelet effect of aspirin.Major
LithiumMefenamic Acid can decrease renal clearance of lithium, leading to toxicity.Major
MethotrexateNSAIDs can reduce renal clearance of methotrexate, increasing risk of bone marrow suppression.Major
Diuretics (Furosemide, Thiazides)NSAIDs may reduce the diuretic and antihypertensive effect and increase risk of renal impairment.Moderate
Antihypertensives (ACE inhibitors, ARBs, Beta-blockers)NSAIDs can attenuate the blood pressure lowering effect.Moderate
Selective Serotonin Reuptake Inhibitors (SSRIs)Increased risk of upper GI bleeding.Moderate
Cholinesterase Inhibitors (Donepezil, Rivastigmine)Dicyclomine antagonizes their effect.Moderate
AlcoholChronic excessive use increases risk of paracetamol hepatotoxicity and GI bleeding with mefenamic acid.Moderate
Antidiabetic Drugs (Sulfonylureas)Mefenamic Acid may potentiate hypoglycemic effect.Moderate

🔁 Alternatives to Dolonex SP

Same composition (Dicyclomine (20mg) + Paracetamol (500mg) + Mefenamic Acid (250mg)), different brands:

Meftal-Spas Spasmo-Proxyvon Plus Pacimol MF Zerodol-SP