Causality assessment · Expected pharmacological effect

Benztropine and Dry mouth: is the FAERS signal real?

n=89 co-reports · PRR 3.2 · ROR 3.2

Benztropine side-effect profile All assessments See in the full list

A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.

Expected pharmacological effect

Benztropine ↔ Dry mouth

n=89 co-reports · PRR 3.2 · ROR 3.2

Benztropine is an anticholinergic used for drug-induced parkinsonism; dry mouth, blurred vision, constipation, and urinary retention are direct consequences of muscarinic blockade (89 co-reports, PRR 3.2). The effects are dose-related and, in older patients, anticholinergic burden can cause confusion and falls, which is why use is minimised in the elderly.

Regulatory basis: benztropine prescribing information — anticholinergic adverse effects; caution in the elderly.

Bradford Hill viewpoint	Status	Note
Temporality (necessary)	met	Dry mouth follows dosing
Strength	met	PRR 3.2, modest
Consistency	met	Universally reproduced
Specificity	met	Specific to anticholinergic drugs
Biological gradient	met	Dose-related
Plausibility	met	Muscarinic-receptor blockade
Coherence	met	Fits the mechanism exactly
Experiment	met	Well described across the class
Analogy	met	Analogous to trihexyphenidyl effects

This table is this page's own qualitative read of the literature cited above, not an automated or citation-gated assessment — see the note at the bottom of this page.

✓ Trial evidence found — Efficacy of Antidepressants in Chronic Back Pain (NCT00964886)

Adverse event	Arm 1 (n=38) · Arm 2 (n=34) · Arm 3 (n=37) · Arm 4 (n=33)
dry mouth	5/17	3/20	4/16	1/17

Post-marketing signal terms appear in this trial's posted adverse-event tables; per-arm counts shown as affected/at-risk. View on ClinicalTrials.gov →