Adults can take Motrin (ibuprofen) every 4 to 6 hours as needed, up to three times per day. The standard over-the-counter dose is 200 to 400 milligrams per dose, with a maximum of 1,200 milligrams in 24 hours. Staying within these limits matters because taking too much or too frequently raises your risk of stomach, kidney, and heart problems.
Adult Dosing Schedule
For the standard 200 mg tablets sold over the counter, you can take one or two tablets (200 to 400 mg) up to three times a day, waiting at least 4 hours between doses. That means no more than six 200 mg tablets in a 24-hour period. If you’re using 400 mg tablets, the same rule applies: one tablet, up to three times daily, with at least 4 hours between doses.
For menstrual cramps specifically, 400 mg every 4 hours as needed is a common recommendation. Regardless of the reason you’re taking it, always take Motrin with food or right after eating. This helps protect your stomach lining from irritation.
How Long You Can Take It Consecutively
If you’re using Motrin for pain, don’t take it for more than 10 days in a row without talking to a doctor. For fever, that limit is shorter: no more than 3 consecutive days. These aren’t arbitrary numbers. The longer you use ibuprofen, the more it suppresses the protective compounds that line your stomach and support kidney function. If you still need pain relief after 10 days, the underlying problem likely needs medical attention rather than more Motrin.
Dosing for Children
Children’s Motrin follows different rules. Kids can take it every 6 to 8 hours, not every 4 to 6 like adults. The dose is based on your child’s weight, not age, though age can be used as a rough guide if you don’t have a recent weight. The American Academy of Pediatrics recommends against giving ibuprofen to any infant under 6 months old, as it hasn’t been shown to be safe in that age group and isn’t FDA-approved for them.
How Quickly It Works
Standard Motrin tablets reach their peak concentration in the bloodstream at about 90 minutes, though you’ll often start feeling some relief before that. Fast-acting formulations (which use different salt forms to speed absorption) can peak in under 50 minutes, sometimes as quickly as 30 minutes. Pain relief from a single dose generally lasts about 4 to 6 hours, which is why that’s the recommended spacing between doses. Research involving over 10,000 patients found that faster-absorbing versions also provided better overall pain relief across 6 hours, with no increase in side effects.
Stomach and Kidney Risks With Frequent Use
Ibuprofen works by blocking an enzyme called COX, which is involved in producing the chemicals that cause pain and inflammation. The problem is that the same enzyme also produces compounds that protect your stomach lining and help regulate blood flow to your kidneys. When you suppress those protective compounds repeatedly, you open the door to ulcers, bleeding, and kidney strain.
Among all common anti-inflammatory painkillers, ibuprofen carries the lowest relative risk of major gastrointestinal events. That’s part of why it’s available over the counter. But “lowest risk” doesn’t mean no risk. People who use these drugs regularly have roughly 19 times higher odds of developing a peptic ulcer compared to non-users. Higher doses make things worse: taking more than recommended can increase the risk of GI complications by 2 to 3 times compared to lower doses. The takeaway is straightforward: use the smallest dose that works and don’t take it longer than you need to.
What Not to Combine With Motrin
Ibuprofen interferes with how your blood clots by affecting platelet function. On its own, this effect is mild. But if you’re taking a blood thinner, whether it’s aspirin, warfarin, or one of the newer oral anticoagulants, adding Motrin on top significantly raises your bleeding risk, especially in the digestive tract. If you take any blood-thinning medication, talk to your doctor before reaching for Motrin.
Alcohol is another concern. It irritates the stomach lining on its own, and combining it with ibuprofen compounds that effect. Regular drinking while taking Motrin increases the chance of stomach bleeding, even at standard doses.
Motrin During Pregnancy
The FDA warns against using ibuprofen at 20 weeks of pregnancy or later. From that point on, it can cause rare but serious kidney problems in the developing baby, leading to dangerously low amniotic fluid levels. After 30 weeks, the risks increase further because ibuprofen can cause a critical blood vessel in the baby’s heart to close prematurely. If you need pain relief during pregnancy, especially in the second half, other options are safer.