Sulfasalazine
Contraindicated
Textbook
Exacerbation of inflammatory bowel disease (IBD).
Avoid combining sulfasalazine with traditional NSAIDs.
Source: G&G 14e · p1112
Drug reference
Paracetamol
Non-opioid analgesic · Analgesic
Also known as Acetaminophen, APAP
START
500–1,000 mg PO q6h PRN
TYPICAL MAX
4,000 mg/day (adult)
STOP IF
Severe hepatic impairment · chronic alcohol use
WATCH
LFTs · overdose risk (>4 g/24h)
CDSCO approvedVaries by formulation and strength (OTC for common doses, Schedule H for higher doses/injectables)Jan AushadhiNPPA price-controlledATC N02BE01
KDIGO 2024 + manufacturer label
- ONSET
- 30min · analgesic effect
- PEAK
- 1h · Cmax
- t½
- 2h · plasma t½
- DURATION
- 6h · single-dose effect
EXCRETION
Hepatic glucuronidation/sulfation · NAPQI
route + CYP
INTERACTIONS
12 major
incl. contraindicated
PREGNANCY
Category B — preferred analgesic across all trimesters
FDA category + note
Top interactionssee all 12 →
- SulfasalazineContraindicatedTextbookG&G 14e · p1112
- AlcoholSevereTextbook-citedKDT 7e · p950
- AminoglycosideSevereTextbookKDT 7e · p746
- AminoglycosidesSevereTextbookKDT 7e
Available in India
1,711 branded formulations and 5,576 fixed-dose combinations. Look up specific brands in the Drugs workspace.
Jan Aushadhi — generic available at GoI pharmacies
Mechanism
Primarily inhibits prostaglandin synthesis in the central nervous system (CNS), likely by reducing COX-1 and COX-2 activity in the brain and possibly through a COX-3 mechanism. It also modulates serotonergic descending pain pathways. This central action leads to antipyretic and analgesic effects, with minimal peripheral anti-inflammatory activity.
Indications
Mild to moderate pain (e.g., headache, muscle ache, menstrual pain, toothache, osteoarthritis)Feverheadachemild migrainemusculoskeletal paindysmenorrhoeaosteoarthritisantipyresis (especially in children)
Dosing
- Adult
- Oral: 500 mg to 1000 mg every 4-6 hours as needed. Intravenous: 1000 mg every 6 hours or 650 mg every 4 hours.
- Pediatric
- Oral: 10-15 mg/kg per dose every 4-6 hours as needed. Max 60 mg/kg/day or 4000 mg/day (whichever is less). Intravenous: 15 mg/kg every 6 hours or 12.5 mg/kg every 4 hours.
- Renal adjustment
- CrCl 10-50 mL/min: Administer every 6 hours. CrCl <10 mL/min: Administer every 8 hours.
- Hepatic adjustment
- Contraindicated in severe hepatic impairment. In moderate impairment, dose reduction and close monitoring are advised.
- Geriatric
- No specific dose adjustment for age alone; consider overall renal and hepatic function.
- Max dose
- (Pediatric: Max 75 mg/kg/day or 4000 mg/day, whichever is less)
Pharmacokinetics
Onset
Oral: 30-60 minutes. Intravenous: 5-10 minutes (analgesia), 30 minutes (antipyresis).
Peak effect
Oral: 0.5-2 hours. Intravenous: 1 hour.
Duration
4-6 hours
Half-life
1-4 hours (typically 2-3 hours in adults)
Bioavailability
Oral: 60-90% (dose-dependent)
Protein binding
10-25% at therapeutic concentrations
Metabolism
Primarily hepatic, via conjugation with glucuronic acid (45-55%) and sulfate (25-35%). A small portion is metabolized by cytochrome P450 enzymes (CYP2E1, CYP1A2, CYP3A4) to a toxic intermediate (NAPQI), which is detoxified by glutathione.
Excretion
Primarily renal (90-100% within 24 hours as conjugated metabolites)
Contraindications
- Severe hepatic impairment or active liver disease
- Hypersensitivity to paracetamol
- premature infants (< 2 kg)
Side effects
Common
NauseaVomitingAbdominal painHeadacheInsomnianausea (occasionally)rashes (occasionally)leukopenia (rare)gastric irritation (insignificant)
Serious
- Hepatotoxicity (especially with overdose)
- Acute Kidney Injury (rare)
- Severe skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis)
- Allergic reactions
- Blood dyscrasias (e.g., thrombocytopenia, agranulocytosis - very rare)
- hepatotoxicity
- hepatic necrosis (from overdosage)
- acute paracetamol poisoning (centrilobular hepatic necrosis, renal tubular necrosis, hypoglycaemia, coma, fatality)
- hepatotoxicity (in chronic alcoholics even with 5–6 g)
Pregnancy & lactation
Pregnancy
Category B — preferred analgesic across all trimesters
Lactation
Excreted in breast milk in small amounts; generally considered compatible with breastfeeding when used at therapeutic doses.
Drug interactions
Alcohol
Severe
Textbook-cited
Reduced threshold for paracetamol hepatotoxicity
Limit paracetamol to less than 3g/day in chronic alcohol users
Source: KDT 7e · p950
Aminoglycoside
Severe
Textbook
Increased risk of nephrotoxicity.
Avoid concurrent use.
Source: KDT 7e · p746
Aminoglycosides
Severe
Textbook
Increased aminoglycoside levels and potential toxicity.
Monitor aminoglycoside levels and renal function; adjust dosage as needed.
Source: KDT 7e
Anticoagulants
Severe
Textbook
Increased risk of gastrointestinal bleed.
Monitor for bleeding; consider alternative analgesics or gastroprotective agents.
Source: KDT 7e
Ciprofloxacin
Severe
Textbook
Enhanced CNS toxicity, seizures reported.
Source: KDT 7e
Citalopram
Severe
Textbook
Increased risk of gastrointestinal bleed.
Monitor for bleeding; consider gastroprotective agents or alternative analgesics.
Source: KDT 7e
Clopidogrel
Severe
Textbook
Increased bleeding risk.
Exercise extra caution and monitor for signs of bleeding.
Source: G&G 14e
Corticosteroids
Severe
Textbook
Increased risk of gastrointestinal bleed.
Monitor for bleeding; consider gastroprotective agents.
Source: KDT 7e
Cyclosporine
Severe
Textbook
Increased nephrotoxicity.
Avoid concomitant use or monitor renal function closely.
Source: KDT 7e
Dapoxetine
Severe
Textbook
Increased risk of gastrointestinal bleed.
Monitor for bleeding; consider gastroprotective agents or alternative analgesics.
Source: KDT 7e
Enalaprilat
Severe
Textbook
Reduced effectiveness of ACE inhibitors. Marked hyperkalemia, potentially leading to cardiac arrhythmia.
Use with caution, especially in the elderly and in patients with hypertension, diabetes mellitus, or ischemic heart disease.
Source: G&G 14e · p836
Related guidelines
Other Non-opioid analgesic drugs
Ask House about Paracetamol
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: KD Tripathi 7e, Katzung, BNF, Harriet Lane·Verified: 2026-05-17 · House clinical team·Cockpit curated: 2026-05-16