From the FDA Drug Label
The peak analgesic effect of ketorolac tromethamine occurs within 2 to 3 hours The time it takes for Toradol (Ketorolac) to take effect is 2 to 3 hours for peak analgesic effect, as stated in the drug label 1.
From the Research
Onset of Action of Toradol (Ketorolac)
The onset of action of Toradol (Ketorolac) can vary depending on the route of administration.
- Intramuscular administration: The maximum plasma concentrations are achieved in 45-50 minutes and peak analgesic effects in about one to two hours following intramuscular injection 2.
- Oral administration: The absorption of ketorolac is rapid, with Cmax being attained between 20 to 60 min 3.
- Intravenous administration: Pain reduction by at least 50% occurred in 25% of patients within 20 min (ketorolac 10 mg) 4.
Comparison with Other Analgesics
The speed of onset of analgesia of intravenous ketorolac was compared to morphine and placebo in a study.
- The pain reduction time for morphine (10 mg) was significantly shorter than that for ketorolac (P = 0.01) or placebo (P < 0.01) 4.
- Intramuscular ketorolac provides analgesia equivalent to commonly used doses of meperidine and morphine 5.
Variability in Onset of Action
There is variability in the onset of action of ketorolac, with some studies reporting a prolonged onset to analgesic action (30-60 min) 5.
- The use of intravenous ketorolac has been less well studied, but it has analgesic potency and may be useful in supplementing parenteral opiates 5.