Drug interactions
Pyridostigmine + Scopolamine
Severity: Moderate
Pyridostigmine and Scopolamine: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Pyridostigmine increases acetylcholine by inhibiting cholinesterase, while scopolamine blocks muscarinic receptors, so they oppose each other. Scopolamine can mask the muscarinic side effects of pyridostigmine such as cramping, salivation and bradycardia. This may hide early signs of cholinergic excess, although nicotinic effects at the neuromuscular junction are not blocked.
What this interaction means in plain words
Pyridostigmine and Scopolamine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Pyridostigmine belongs to Central Nervous System; Scopolamine belongs to Respiratory.
Why it happens
Pharmacodynamic antagonism at muscarinic receptors between an antimuscarinic and a cholinesterase inhibitor.
What to do
Monitor myasthenia control and for muscarinic symptoms. Do not rely on absence of muscarinic signs to exclude cholinergic excess.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Scopolamine
Other interactions of Pyridostigmine
Frequently asked questions
Can I take Pyridostigmine with Scopolamine?
MediHelp rates the interaction as moderate. Pyridostigmine and Scopolamine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Pyridostigmine increases acetylcholine by inhibiting cholinesterase, while scopolamine blocks muscarinic receptors, so they oppose each other. Scopolamine can mask the muscarinic side effects of pyridostigmine such as cramping, salivation and bradycardia. This may hide early signs of cholinergic excess, although nicotinic effects at the neuromuscular junction are not blocked.
How serious is the interaction between Pyridostigmine and Scopolamine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor myasthenia control and for muscarinic symptoms. Do not rely on absence of muscarinic signs to exclude cholinergic excess.
What other medicines interact with Scopolamine?
MediHelp also lists interactions of Scopolamine with, for example, Benzhydrocodone / acetaminophen, Buprenorphine long-acting, Buprenorphine subdermal implant. The full list is on the Scopolamine page.
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