Question explored with the scientific record
What are the risks of taking Fiorinal
The short version: Fiorinal contains three drugs, and the aspirin component alone carries a well-documented risk of gastrointestinal bleeding that is dose-dependent and often underappreciated by patients.
Fiorinal is a combination of butalbital (a barbiturate), aspirin, and caffeine. The evidence you have is almost entirely about the aspirin component, and that evidence is clear and consistent. Aspirin damages the lining of the stomach and small intestine and impairs blood clotting. In a randomized trial of patients taking aspirin after a minor stroke, the odds of upper gastrointestinal bleeding were 3.3 times higher with 300 mg daily and 6.4 times higher with 1200 mg daily compared to placebo [4]. The risk was highest early in treatment [4]. A systematic review found that low-dose aspirin roughly doubles the risk of major gastrointestinal bleeding, with an annual excess of about 1 extra bleed per 833 people treated [6, 9].
The risk is not theoretical. In one study of patients hospitalized for gastrointestinal bleeding, 22% of those who denied taking aspirin had detectable salicylate in their blood [3]. That means people are bleeding from aspirin they did not even remember taking. The bleeding comes from peptic ulcers and acute gastritis, and the risk is higher in people with diabetes, hypertension, or a history of ulcer [5, 11]. Enteric-coated aspirin does not reduce the risk [8, 11].
The butalbital component has its own risks: it is a barbiturate and carries dependence, sedation, and withdrawal potential. The evidence you have on butalbital is a single animal study from 1999 showing it reduces pain signaling in guinea pigs [1]. That tells you nothing about human safety or long-term use.
| Risk | Evidence |
|---|---|
| Upper GI bleeding, aspirin 300 mg daily | Odds ratio 3.3 vs placebo [4] |
| Upper GI bleeding, aspirin 1200 mg daily | Odds ratio 6.4 vs placebo [4] |
| Major GI bleeding, low-dose aspirin | ~2x risk vs no aspirin [6, 9] |
| Annual excess bleeds per 1000 users | ~1.2 per year [6] |
| Patients unaware they took aspirin | 22% of bleeders had salicylate in blood [3] |
The key point: the aspirin in Fiorinal is not a trivial dose. A single Fiorinal tablet typically contains 325 mg of aspirin, which is the same range as the higher-dose arm of the UK-TIA trial [4]. The risk of bleeding is real, dose-dependent, and often happens without warning. The butalbital adds sedation and dependence. There is no long-term safety data for the combination.
My call: Fiorinal carries a meaningful risk of gastrointestinal bleeding from its aspirin component, and the barbiturate adds dependence and sedation. The evidence on the combination is thin, but the aspirin risk alone is well-established and dose-dependent. Confidence: high for the aspirin bleeding risk, moderate for the overall risk-benefit of the combination.
Sources used 8
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Attenuation by Butalbital of Capsaicin‐Induced C‐fos—like Immunoreactivity in Trigeminal Nucleus Caudalis
This study investigates the effects of butalbital on capsaicin-induced c-fos-like immunoreactivity in the trigeminal nucleus caudalis of guinea pigs, demonstrating that butalbital reduces neuronal activation in a dose-dependent manner, potentially implicating GABA receptors as t…
DOI: 10.1046/j.1526-4610.1999.3910697.x -
Aspirin and Gastrointestinal Bleeding
In 123 bleeding patients, plasma salicylate testing detected aspirin ingestion in 22% of those denying it, bringing total exposure to 68%, and aspirin takers had higher rates of peptic ulcer and acute gastritis/duodenitis bleeding.
DOI: 10.1159/000198348 -
Risks of gastrointestinal bleeding during secondary prevention of vascular events with aspirin--analysis of gastrointestinal bleeding during the UK-TIA trial.
In the UK-TIA trial, aspirin at 300 mg and 1200 mg daily dose-dependently increased upper gastrointestinal bleeding and hospitalisation for bleeding in patients after TIA or minor ischaemic stroke, with bleeding most likely early in treatment.
DOI: 10.1136/gut.37.4.509 -
Association of cardiometabolic risk burden with gastrointestinal bleeding in aspirin users
This prospective UK Biobank cohort study investigates whether the cumulative burden of cardiometabolic risk factors (obesity, diabetes, dyslipidemia, hypertension) is associated with higher risk of aspirin-related gastrointestinal bleeding in individuals with ischemic cardiovasc…
DOI: 10.1186/s12876-025-04347-3 -
Review article: gastrointestinal bleeding with low‐dose aspirin – what's the risk?
Low-dose aspirin doubles the risk of major gastrointestinal bleeding, with an annual attributable incidence of 0.12% and a number-needed-to-harm of 833.
DOI: 10.1111/j.1365-2036.2006.03077.x -
Risk of upper gastrointestinal bleeding associated with use of low-dose aspirin
This cohort study investigates the risk of hospitalization for upper gastrointestinal bleeding associated with low-dose aspirin use, revealing a significant increase in risk, particularly when combined with other nonsteroidal anti-inflammatory drugs.
DOI: 10.1111/j.1572-0241.2000.02248.x -
Bleeding Risk with Long-Term Low-Dose Aspirin: A Systematic Review of Observational Studies
This systematic review analyzes the bleeding risks associated with long-term low-dose aspirin therapy, revealing a significant increase in gastrointestinal bleeding and intracranial hemorrhage compared to non-use, while also assessing the influence of concomitant medications and…
DOI: 10.1371/journal.pone.0160046 -
Gastrointestinal lesions and complications of low-dose aspirin in the gastrointestinal tract
This review summarizes how low-dose aspirin causes a spectrum of gastrointestinal lesions and complications across the GI tract, highlights risk factors and mechanisms, evaluates clinical outcomes (including bleeding and perforation), and discusses potential mitigations and emer…
DOI: 10.1016/j.bpg.2012.01.016