Atropine

Increased antimuscarinic side-effects may occur in coadministration of atropine with phenothiazines and clozapine.

Many drugs have antimuscarinic effects; concomitant use of two or more such drugs can increase side-effects such as dry mouth, urine retention, and constipation; concomitant use can lead to confusion in the elderly.

Increased antimuscarinic side-effects may occur in coadministration of atropine with tricyclic antidepressants and mono-amine oxidase inhibitors (MAOIs).

Marked impairment of attention can occur with alcohol, sufficient to make driving more hazardous.

The common side-effect of a dry mouth with atropine may result in the failure of sublingual nitrates to dissolve, thereby reducing their effectiveness.

Possible antagonism of effect of parasympathomimetics in coadministration with atropine.

Increased antimuscarinic side-effects may occur in coadministration of atropine with some antihistamines.

Increased antimuscarinic side-effects may occur in coadministration of atropine with amantadine.

Increased antimuscarinic side-effects may occur with disopyramide and atropine compination.

The absorption of ketoconazole can be reduced by atropine.

The absorption of levodopa may possibly be reduced when administered with antimuscarinic agents.

There is possible antagonism of gastrointestinal effects of metoclopramide and domperidone in coadministration with atropine.

The absorption of mexiletine can be delayed by atropine but the extent of absorption is unaltered and no special precautions are necessary.

Hypertensive and other serious adverse effects of phenylephrine absorbed from eye drops may be markedly increased by atropine.

Atropine may aggravate gastro-oesophageal reflux.

Use of atropine with caution in patients with urinary retention, acute myocardial infarction, hypertension, conditions associated with tachycardia (including hyperthyroidism, cardiac insufficiency, cardiac surgery), pyrexia and diarrhoea.

Atropine crosses the placenta. Studies in humans have not been done and only limited information is available from animal studies. Animal studies are insufficient with respect to reproductive toxicity.

Intravenous administration of atropine during pregnancy or at term may cause tachycardia in foetus. Atropine should only be administered to pregnant women if the benefits outweigh the risks to the foetus.

Trace amounts of atropine appear in the breast milk and may cause antimuscarinic effects in the infant; lactation may be inhibited.

Fertility

There are no adequate preclinical fertility data with atropine, and no epidemiological data.

Atropine may cause blurred vision, drowsiness, confusion, hallucinations and other neuro-psychiatric effects. Patients should be advised that they should not drive, operate machinery or take part in any activities that could, if they are affected, put them or others at risk. Warn patients not to drive or operate hazardous machinery until vision is clear.