Formulary
Diclofenac: Uses, Dosing, Side Effects and Indian Brand Names
Diclofenac is a potent non-selective NSAID with COX-2 preference, widely used in India for pain and inflammation. It caused the Indian vulture crisis leading to a ban on veterinary use in 2006.
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Clinically reviewed by Awaiting clinical review
Diclofenac: Uses, Dosing, Side Effects and Indian Brand Names
Diclofenac is a potent non-selective NSAID with COX-2 preference, widely used in India for pain and inflammation. It caused the Indian vulture crisis leading to a ban on veterinary use in 2006.
NEET PG High-Yield: Diclofenac caused the Indian vulture crisis -- a favourite environmental pharmacology question. IM diclofenac is first-line for renal colic. Remember the 'triple whammy' nephrotoxicity: NSAID + ACE inhibitor/ARB + diuretic. NSAIDs are contraindicated in the third trimester of pregnancy (ductus arteriosus closure).
Clinical overview
Diclofenac is one of the most widely prescribed NSAIDs in India and globally, valued for its potent anti-inflammatory, analgesic, and antipyretic properties. It is commonly used for musculoskeletal pain, post-operative pain, renal colic, dysmenorrhoea, and inflammatory conditions like rheumatoid arthritis and osteoarthritis. In India, diclofenac is available in numerous formulations including tablets, injections, topical gels, and eye drops. Notably, intramuscular diclofenac is one of the most commonly administered injections in Indian clinical practice for acute pain, though it carries a risk of sciatic nerve palsy when injected incorrectly into the buttock. The drug has gained notoriety for causing near-extinction of the Indian vulture population (Gyps species) when vultures consumed carcasses of diclofenac-treated livestock. This led the Indian government to ban veterinary diclofenac in 2006 under the Drugs and Cosmetics Act. Like other non-selective NSAIDs, diclofenac carries risks of gastrointestinal bleeding, cardiovascular events (increased MI and stroke risk, especially with prolonged use), and renal toxicity. The cardiovascular risk was highlighted by the MEDAL programme, and current guidelines recommend the lowest effective dose for the shortest duration. Topical formulations (Voveran Emulgel) offer a better safety profile for localised musculoskeletal pain.
Pharmacological class
Diclofenac belongs to the Non-steroidal anti-inflammatory drug (NSAID; phenylacetic acid derivative) class. Diclofenac non-selectively inhibits both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), with a relative preference for COX-2. It reduces prostaglandin synthesis, thereby decreasing inflammation, pain, and fever. Additionally, it inhibits the lipoxygenase pathway, reducing leukotriene production, and modulates the arachidonic acid/thromboxane pathway, contributing to its potent anti-inflammatory effect.
Indian brand names and formulations
Available as: Voveran (Novartis India), Dynapar (Troikaa Pharmaceuticals), Reactin (Wockhardt), Diclomol (Stadmed).
Tablets (50 mg, 100 mg SR), Injection (75 mg/3 mL for IM use), Topical gel (1%), Eye drops (0.1%), Suppositories (50 mg, 100 mg), Transdermal patch
Regulatory status
Diclofenac is classified under Schedule H in India under the Drugs and Cosmetics Act, 1940. Schedule H prescription drug. Veterinary use is BANNED in India since 2006 (to protect vulture populations). Human formulations are freely available on prescription. The ban is enforced under the Drugs and Cosmetics Act.
Indications
- Rheumatoid arthritis and osteoarthritis
- Acute musculoskeletal pain and soft tissue injuries
- Post-operative pain
- Renal colic (IM injection)
- Dysmenorrhoea
- Acute gout
- Ankylosing spondylitis
- Ophthalmic: post-cataract surgery inflammation (eye drops)
Dosing
Oral: 50 mg BD-TDS or 75 mg BD (max 150 mg/day). SR tablets: 100 mg once daily. IM: 75 mg deep gluteal injection (avoid sciatic nerve -- inject in upper outer quadrant only). Topical gel: apply 3-4 times daily to affected area. Eye drops: 1 drop QID post-operatively. Use the lowest effective dose for the shortest possible duration. Elderly: reduce dose; monitor renal function.
Contraindications
- Active peptic ulcer disease or GI bleeding
- Severe heart failure (NYHA III-IV)
- Severe renal impairment (eGFR <30 mL/min)
- History of NSAID-induced asthma or urticaria (aspirin triad)
- Third trimester of pregnancy (premature closure of ductus arteriosus)
- Concurrent anticoagulant therapy (relative contraindication)
- Post-CABG surgery (perioperative NSAID use increases cardiovascular events)
Adverse effects
- Gastric erosion, peptic ulcer, GI bleeding (most significant risk)
- Dyspepsia, nausea, abdominal pain
- Cardiovascular events (increased MI, stroke risk with prolonged use)
- Renal impairment (reduced GFR, sodium and water retention, hyperkalaemia)
- Hypertension exacerbation
- Hepatotoxicity (elevated transaminases)
- Platelet dysfunction (bleeding tendency)
- Hypersensitivity reactions (bronchospasm in aspirin-sensitive patients)
- Sciatic nerve palsy (with improper IM injection technique)
Drug interactions
- Anticoagulants (warfarin) -- increased bleeding risk (both pharmacokinetic displacement and pharmacodynamic antiplatelet effects)
- ACE inhibitors/ARBs + diuretics -- 'triple whammy' renal toxicity risk
- Methotrexate -- reduced renal clearance of methotrexate, causing toxicity
- Lithium -- reduced renal clearance, risk of lithium toxicity
- SSRIs -- additive GI bleeding risk
- Corticosteroids -- additive GI toxicity
Pregnancy and lactation
Category B (first and second trimester), Category D (third trimester). Avoid in the third trimester -- causes premature closure of the ductus arteriosus, oligohydramnios, and delayed labour. NSAIDs also inhibit implantation and may impair fertility. Paracetamol is the safer alternative for pain in pregnancy.
Exam-style clinical scenario
A 45-year-old man presents with sudden-onset severe colicky left flank pain radiating to the groin. CT KUB reveals a 6 mm left ureteric calculus. What analgesic provides the best pain relief? Answer: IM diclofenac (75 mg) is the analgesic of choice for acute renal colic. NSAIDs are superior to opioids for ureteric colic as they reduce ureteric smooth muscle spasm by inhibiting prostaglandin-mediated ureteric peristalsis, in addition to their analgesic effect. Diclofenac also reduces GFR and urine output, decreasing intraluminal pressure.
Cost in India
INR 15-35 per strip of 10 tablets (50 mg); IM injection: INR 10-20 per ampoule; Gel: INR 50-100
Clinical governance
Author: MedNext Editorial Team. Clinical reviewer: Awaiting clinical review. Jurisdiction: India (Drugs and Cosmetics Act, 1940). Sources: CIMS India, Indian Pharmacopoeia. Publication state: Awaiting clinical review. Correction: Report errors at support@mednext.academy.
Frequently Asked Questions
Why did diclofenac cause the Indian vulture population crash?
Vultures consuming carcasses of livestock treated with diclofenac developed visceral gout and renal failure, leading to death within days. Vultures lack the hepatic enzyme capacity to metabolise diclofenac. The Gyps vulture population in India declined by >97% between the 1990s and 2007. The Government of India banned veterinary diclofenac in 2006, and meloxicam was identified as a safe veterinary alternative.
What is the 'aspirin triad' and how does it relate to diclofenac?
The aspirin triad (Samter's triad) consists of aspirin/NSAID sensitivity, nasal polyposis, and bronchial asthma. Patients with this triad can develop life-threatening bronchospasm with any NSAID, including diclofenac. The mechanism involves COX-1 inhibition diverting arachidonic acid toward the lipoxygenase pathway, increasing leukotriene synthesis (LTC4, LTD4), which causes bronchospasm.
Why is diclofenac preferred over opioids for renal colic?
Diclofenac reduces prostaglandin-mediated afferent arteriolar vasodilation, decreasing GFR and urine production, which lowers intrapelvic pressure. It also directly reduces ureteric smooth muscle spasm. Unlike opioids, it does not cause nausea/vomiting (which complicates colic), does not cause sedation in the acute setting, and provides sustained analgesia. Multiple RCTs show NSAIDs are more effective than opioids for ureteric colic.
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