free · label-sourced · drug vs placebo · 37 medications
Side-effect rates,
straight from the label
the trials behind every approved medication counted who got which side effects — on the drug and on placebo — and the FDA label publishes the table. almost nobody reads it there. pick a medication and see the manufacturer's own numbers, side by side, with every caveat the label attaches.
the label's own caveat: "Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice."
what these numbers cover: The data in the two tables below are estimates of adverse reaction incidence among adult patients who participated in: 4-week placebo-controlled clinical studies with XANAX dosages up to 4 mg per day for the acute treatment of generalized anxiety disorder (Table 1); short-term (up to 10 weeks) placebo-controlled clinical studies with XANAX dosages up to 10 mg per day for panic disorder, with or without agoraphobia (Table 2).
what makes the table: "Table 2: Adverse Reactions Occurring in ≥1% in XANAX-treated Patients and Greater than Placebo-treated Patients in Placebo-Controlled Trials (Up to 10 Weeks) for Panic Disorder"
| reaction | XANAX (n=1388) | Placebo (n=1231) | difference per 100 people |
|---|---|---|---|
| drowsiness | 77% | 43% | about 34 more |
| fatigue and tiredness | 49% | 42% | about 7 more |
| impaired coordination | 40% | 18% | about 22 more |
| irritability | 33% | 30% | about 3 more |
| memory impairment | 33% | 22% | about 11 more |
| cognitive disorder | 29% | 21% | about 8 more |
| decreased libido | 14% | 8% | about 6 more |
| dysarthria | 23% | 6% | about 17 more |
| confusional state | 10% | 8% | about 2 more |
| increased libido | 8% | 4% | about 4 more |
| change in libido (not specified) | 7% | 6% | about 1 more |
| disinhibition | 3% | 2% | about 1 more |
| talkativeness | 2% | 1% | about 1 more |
| derealization | 2% | 1% | about 1 more |
| constipation | 26% | 15% | about 11 more |
| increased salivation | 6% | 4% | about 2 more |
| rash | 11% | 8% | about 3 more |
| increased appetite | 33% | 23% | about 10 more |
| decreased appetite | 28% | 24% | about 4 more |
| weight gain | 27% | 18% | about 9 more |
| weight loss | 23% | 17% | about 6 more |
| micturition difficulties | 12% | 9% | about 3 more |
| menstrual disorders | 11% | 9% | about 2 more |
| sexual dysfunction | 7% | 4% | about 3 more |
| incontinence | 2% | 1% | about 1 more |
Table 2 (panic disorder, up to 10 weeks). The label also carries a GAD table — Table 1, "Adverse Reactions Occurring in ≥1% in XANAX-treated Patients and Greater than Placebo-treated Patients in Placebo-Controlled Trials for Generalized Anxiety" (the caption as printed ends at "Generalized Anxiety"; XANAX n=565 vs placebo n=505) — see the label. In the label filing the first block of Table 2 rows carries no organ-class header; later rows are grouped under Gastrointestinal disorders, Skin and subcutaneous tissue disorders, and Other.
discontinuation — what the label does and does not state: This label does NOT state an overall percentage of patients discontinuing due to adverse reactions. What it provides instead: "In a larger database comprised of both controlled and uncontrolled studies in which 641 patients received XANAX, discontinuation-emergent symptoms which occurred at a rate of over 5% in patients treated with XANAX and at a greater rate than the placebo-treated group are shown in Table 3."
discontinuation-emergent symptoms (label Table 3 — XANAX-treated patients only, no placebo column printed): "Table 3: Discontinuation-Emergent Symptom Incidence Reported in ≥5% of XANAX-treated Patients and > Placebo-treated Patients" (n=641; drug arm only): insomnia 29.5%; light-headedness 19.3%; anxiety 19.2%; fatigue and tiredness 18.4%; abnormal involuntary movement 17.3%; headache 17.0%; nausea/vomiting 16.5%; sweating 14.4%; diarrhea 13.6%; weight loss 13.3%; decreased appetite 12.8%; tachycardia 12.2%; decreased salivation 10.6%; irritability 10.5%; cognitive disorder 10.3%; blurred vision 10.0%; muscular twitching 6.9%; impaired coordination 6.6%; muscle tone disorders 5.9%; weakness 5.8%; memory impairment 5.5%; depression 5.1%; confusional state 5.0%. These are discontinuation-EMERGENT symptoms (on stopping the drug), not discontinuation-due-to-adverse-reaction rates — different constructs.
dependence and withdrawal (label sections 5.3 and 6.1): "Even after relatively short-term use at doses of ≤4 mg/day, there is some risk of dependence. Spontaneous reporting system data suggest that the risk of dependence and its severity appear to be greater in patients treated with doses greater than 4 mg/day and for long periods (more than 12 weeks)." … "In some cases, benzodiazepine users have developed a protracted withdrawal syndrome with withdrawal symptoms lasting weeks to more than 12 months." … "There have also been reports of withdrawal seizures upon rapid decrease or abrupt discontinuation of XANAX."
how to read the table
the drug column is how many trial patients per hundred reported the reaction; the placebo column is the same count among patients on an identical-looking sugar pill. the difference column is the arithmetic between them — roughly the share the trials attribute to the drug itself. two cautions the labels themselves insist on: these tables only include reactions above each label's own reporting threshold, and rates measured in one set of trials can't be compared to rates from another drug's trials. that second point is why this page shows one medication at a time and never ranks them.
Frequently asked questions
Where do these side-effect percentages come from?
from each medication’s current FDA label — the adverse-reactions table the manufacturer itself publishes from the placebo-controlled registration trials, as posted on DailyMed. every drug on this page links its label, and we transcribe the numbers exactly as printed. nothing here comes from review sites, forums, or our own analysis.
Why show the placebo column?
because it’s the only honest way to read the drug column. headaches, nausea and insomnia happen to people taking sugar pills too — the placebo rate is the background noise. the difference between the two columns is the part the trials attribute to the drug, and the labels publish both numbers for exactly this reason.
Will I personally get these side effects?
nobody can tell you that — not this page, and not anything else that isn’t your prescriber looking at your situation. these are rates from trial populations over the trial durations, and the labels themselves warn that rates from one set of trials can’t be directly compared to another. what this page does is smaller and more honest: it shows you what the manufacturer reported, so the conversation with your prescriber starts from the published numbers.
Why do some medications show no table?
older drugs were approved before labels carried placebo-controlled incidence tables — hydroxyzine dates to 1956. where a label publishes no drug-vs-placebo table, we say exactly that and show what the label provides instead, rather than substituting numbers from somewhere weaker.
the bigger picture
side-effect rates are one input into a decision that also involves how long the approval trials ran, what the boxed warnings say, and what stopping looks like — our medication library walks each drug's full public record. and whatever you decide about medication, veisund is free anonymous peer support from people who've sat with the same decision — not medical advice, just company in it.
this page transcribes published FDA-label data and is not medical advice; never start, stop or change a medication without your prescriber. labels change — each drug links the label version we transcribed. if you are in crisis, call or text 988 (suicide & crisis lifeline) — free, confidential, 24/7.