Atropine is an injection used in emergencies to speed up the heart when it beats too slowly (symptomatic bradycardia) and to reduce secretions before anaesthesia. Eye drops also exist to dilate the pupil during eye examinations.
Also known as: Sulfato de atropina
Atropine plus hydroxyzine adds anticholinergic effects (tachycardia, dry mouth, urinary retention) and sedation.
Both have anticholinergic activity; hydroxyzine adds H1-blockade sedation.
Heart rate, urination, level of consciousness.
Tachycardia, urinary retention, paradoxical agitation.
In premedication, doses should be reduced; monitor for anticholinergic signs.
DailyMed — Atropine Sulfate Injection and Hydroxyzine Pamoate labels (additive anticholinergic effects): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8663ff94-8bea-4061-9fd5-3ab2e85e862e
Atropine plus imipramine adds anticholinergic effects (dry mouth, constipation, urinary retention, tachycardia, confusion in the elderly).
Imipramine has potent anticholinergic activity that adds to that of atropine.
Anticholinergic signs, especially in the elderly.
Acute urinary retention, confusion, tachycardia.
Avoid the combination when possible; use minimum doses for the shortest time.
DailyMed — Tofranil (imipramine) label, additive anticholinergic effects: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=649837df-147f-436c-9553-32ffecf4c6f1
Atropine can reduce levodopa absorption (delayed gastric emptying), lowering its effect.
Anticholinergic drugs delay gastric emptying, delaying and limiting levodopa absorption in the small intestine.
Motor fluctuations (on-off) after atropine administration.
Sudden worsening of mobility, rigidity.
Monitor motor response; consider separating levodopa and atropine dosing.
DailyMed — Sinemet (carbidopa/levodopa) label, drugs delaying gastric emptying: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=39d79ade-8ee0-40ba-9fdd-13045b8ddbdf
No documented food or drink interactions.
Antimuscarinics dilate the pupil and precipitate angle-closure glaucoma attacks.
Exclude angle-closure glaucoma before any use.
Prontuário Terapêutico INFARMED, 10.1 (antimuscarinic effects — angle-closure glaucoma); site monograph (atropine).
Antimuscarinics increase urinary retention in prostatic hyperplasia.
Ask about urinary symptoms; avoid if previous retention.
Prontuário Terapêutico INFARMED, 10.1 (antimuscarinics — urinary retention, prostatic hyperplasia).
No specific entry in the Prontuário Annex 1; it crosses the placenta and, at therapeutic doses, there are no teratogenicity reports. At high doses near term it may cause fetal tachycardia and neonatal antimuscarinic depression.
Use only if indicated (symptomatic bradycardia, anaesthesia premedication) at the lowest effective dose; monitor fetal heart rate at high doses near term.
Use with caution; antimuscarinic effects may occur in the infant (Prontuário, Annex 2, l. 42248) — at the usual single dose the risk is small; high or repeated doses may reduce milk production (anticholinergic effect).
Prontuário Terapêutico INFARMED — Annex 2: "Atropine — Use with caution; antimuscarinic effects in the infant" (l. 42248). Annex 1: no specific entry. EMC-UK (MHRA) — Atropine SmPC.
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Reference anticholinergic in symptomatic bradycardia and as cholinergic antidote; dose-graded effects across the antimuscarinic quadrant (secretions → heart rate → GI → organ → CNS).
Competitive antagonist at muscarinic receptors (M1–M5): blocks post-ganglionic parasympathetic acetylcholine action — in the heart removes vagal tone (tachycardia), in glands reduces secretions, in smooth muscle decreases motility, in the pupil causes mydriasis/cycloplegia. Crosses the BBB (central effects) and the placenta.
IV: immediate (peak < 2 min). IM: rapid and complete. Oral: absorbed but partial first pass (bioavailability 10–25%); ophthalmic effect (eye drops) is local and prolonged.
Hepatic hydrolysis to tropine and tropic acid (~50%); the rest excreted renally unchanged. No clinically relevant CYP interactions — renal excretion dominant.
2–5 h (plasma); mydriasis and cycloplegia last days (ocular tissue binding), tachycardia 2–3 h after IV.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
