muscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other additive CNS effects may also occur.
Physostigmine: Coadministration of atropine and physostigmine may produce a mutually antagonistic effect.
Potassium: Drugs that decrease GI motility may increase the risk of GI irritation from sustained-release solid oral dosage forms of potassium salts. The use of solid oral dosage forms of potassium chloride is contraindicated in patients taking glycopyrrolate oral solution. In one study, healthy subjects were examined for GI irritation following the administration of oral potassium for at least 7 days. Glycopyrrolate was coadministered to some subjects in order to study the additional effects of delayed gastric emptying. Results indicated that subjects administered wax-matrix tablets had the highest incidence of erosions (43%) and ulcers (11%). Evidence of GI irritation was less frequent among subjects receiving liquid (0%) and microencapsulated (10.5% erosions, 1.2% ulcers) formulations. Therefore, if oral potassium supplementation is necessary in a patient taking antimuscarinics, a liquid formulation should be considered. If a solid formulation is being prescribed, the patient should be counseled on strategies that can be used to avoid GI irritation such as taking potassium products only while seated or standing, remaining upright for 10 minutes after each dose, and ingesting each dose with plenty of fluids.
Pramlintide: Pramlintide therapy should not be considered in patients taking medications that alter gastric motility, such as anticholinergics. Pramlintide slows gastric emptying and the rate of nutrient delivery to the small intestine. Medications that have depressive effects on GI could potentiate the actions of pramlintide.
Procainamide: The anticholinergic effects of procainamide may be significant and may be enhanced when combined with anticholinergics. Anticholinergic agents administered concurrently with procainamide may produce additive antivagal effects on AV nodal conduction, although this is not as well documented for procainamide as for quinidine.
Prochlorperazine: Additive anticholinergic effects may be seen when anticholinergics are used concomitantly with phenothiazines, including prochlorperazine. Clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other additive CNS effects may also occur.
Promethazine: Additive anticholinergic effects may be seen when anticholinergics are used concomitantly with phenothiazines, including promethazine. Clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other additive CNS effects may also occur.
Proton pump inhibitors: The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
Pseudoephedrine: Atropine blocks the vagal reflex bradycardia caused by pseudoephedrine, and increases its pressor effect. Patients need to be asked whether they have taken pseudoephedrine before recei |
