Analgesic Selection for Acute Pain Presentations

Acute Abdominal Pain

Intravenous paracetamol 1 g every 6 h is recommended as the optimal first‑line analgesic because it provides effective pain relief without the gastrointestinal bleeding, renal toxicity, or cardiovascular complications associated with NSAIDs such as diclofenac. 1
In emergency general‑surgery patients, incorporating IV paracetamol into multimodal analgesic regimens is cost‑effective, shortens hospital length of stay, and reduces complications compared with opioid‑only strategies. 1
Intramuscular diclofenac should be avoided in abdominal surgery because of increased risk of anastomotic dehiscence, technical failures, and impaired wound healing. 1
Tramadol should be reserved for moderate‑to‑severe abdominal pain that is not adequately controlled with paracetamol; it is not a first‑line option. 3

Intravenous paracetamol is the preferred first‑line agent, offering effective relief with minimal adverse effects. 1

Intravenous paracetamol 1 g every 6 h is appropriate as first‑line therapy for non‑cardiac, musculoskeletal chest pain. 1
Non‑steroidal anti‑inflammatory drugs (e.g., diclofenac) should be avoided in patients with known cardiovascular disease until safety is confirmed, because NSAIDs increase cardiovascular risk. 5

Intramuscular diclofenac 50 mg (up to 200 mg per day) provides superior analgesia to paracetamol alone in young, otherwise healthy patients with acute mechanical back pain. 6
A combination of paracetamol plus diclofenac yields greater pain relief than either agent alone; however, therapy should start with paracetamol monotherapy and add diclofenac only if needed. 1

Diclofenac is contraindicated in the presence of any of the following (based on evidence from World Journal of Emergency Surgery and Anaesthesia):

Tramadol is not recommended as a first‑line analgesic for any of the acute pain presentations discussed, because it offers no superiority over paracetamol and carries a higher adverse‑effect burden. 3
Clinical guidelines place tramadol as a second‑line option, to be used only when pain remains moderate‑to‑severe despite adequate non‑opioid therapy. 6
Tramadol may be considered in situations where opioid analgesia is required but strong opioids are not yet indicated, provided patient‑specific risk factors are evaluated. 5

Medication	Recommended Dose	Maximum Daily Dose	Key Notes
IV Paracetamol	1 g every 6 h	4 g/24 h (age < 60 yr) ; 3 g/24 h (age ≥ 60 yr)	First‑line for most acute pain presentations. [1]
IM Diclofenac	50–75 mg every 8–12 h	200 mg/24 h	Use only when no contraindications are present. [6]
IV Tramadol	50–100 mg every 4–6 h PRN	400 mg/24 h	Reserved for breakthrough pain or when non‑opioid agents are insufficient. [3]