What is the Difference Between Neostigmine and Pyridostigmine

The key difference between neostigmine and pyridostigmine is that neostigmine is a more potent medication than pyridostigmine for the treatment of myasthenia gravis.

Myasthenia gravis is a chronic autoimmune disorder. In this condition, autoantibodies destroy the communication between nerves and muscle, resulting in the weakness of the skeletal muscles. Therefore, myasthenia gravis affects the voluntary muscles of the body. These voluntary muscles, especially those that control the eyes, mouth, throat, and limbs. Oral acetylcholine esterase inhibitors are used to treat myasthenia gravis. Neostigmine and pyridostigmine are two oral acetylcholine esterase inhibitors used for the treatment of myasthenia gravis.

CONTENTS

1. Overview and Key Difference
2. What is Neostigmine 
3. What is Pyridostigmine
4. Similarities – Neostigmine and Pyridostigmine
5. Neostigmine vs Pyridostigmine in Tabular Form
6. Summary – Neostigmine vs Pyridostigmine

What is Neostigmine?

Neostigmine is a more potent medication used for the treatment of myasthenia gravis. It is sold under the brand name bloxiverz. It is also a medication used for the treatment of other diseases such as Ogilvie syndrome and urinary retention without the presence of a blockage. Moreover, it is also used in anaesthesia to end the effects of a non-depolarising neuromuscular blocking medication. Normally, this medication is given by injections, either into veins, muscles or under the skin. After a Neostigmine injection, the effects are generally greatest within 30 minutes and last up to 4 hours. Neostigmine interferes and prevents the breakdown of acetylcholine (neurotransmitter) by the acetylcholinesterase enzyme. Furthermore, neostigmine indirectly stimulates both nicotinic and muscarinic receptors. Neostigmine binds to the anionic and ester site of the acetylcholinesterase enzyme, thus blocking the enzyme from breaking down the acetylcholine molecules before these molecules reach the postsynaptic membrane receptors.

The side effects due to the usage of this medication include nausea, increased saliva, crampy abdominal pain, slow heart rate, low blood pressure weakness, and allergic reactions. Neostigmine was first patented in 1931, and it is on the World Health Organization’s List of Essential Medicines.

What is Pyridostigmine?

Pyridostigmine is a less potent medication used for the treatment of myasthenia gravis. It is also used for the treatment of underactive bladders. This medication is used together with atropine to end the effects of neuromuscular blocking medication of non-depolarizing type. Pyridostigmine is typically given orally. However, it can also be given through injections. The effects of pyridostigmine normally begin within 45 minutes and last up to 6 hours.

The common side effects of this medication include nausea, diarrhoea, frequent urination, and abdominal pain. The more serious side effects of pyridostigmine include low blood pressure, weakness, and allergic reactions. Moreover, it is unclear whether the use of this medication in pregnancy is safe or not for the fetus.

Furthermore, pyridostigmine is an acetylcholinesterase enzyme inhibitor in the cholinergic family of medications. This medication works by blocking the action of the acetylcholinesterase enzyme, and it increases the levels of acetylcholine. Pyridostigmine was first patented in 1945, and it is on the World Health Organization’s List of Essential Medicines.

What are the Similarities Between Neostigmine and Pyridostigmine?

• Neostigmine and pyridostigmine are two oral acetylcholine esterase inhibitors used for the treatment of myasthenia gravis.
• Both medications work by blocking the action of the acetylcholinesterase enzyme and increasing the levels of acetylcholine.
• Both medications are on the World Health Organization’s List of Essential Medicines.
• They are used in anaesthesia to end the effects of non-depolarising neuromuscular blocking medication.

What is the Difference Between Neostigmine and Pyridostigmine?

Neostigmine is a more potent medication used for the treatment of myasthenia gravis, while pyridostigmine is a less potent medication used for the treatment of myasthenia gravis. Thus, this is the key difference between neostigmine and pyridostigmine. Furthermore, neostigmine was patented in 1931, while pyridostigmine was patented in 1945.

The below infographic presents the differences between neostigmine and pyridostigmine in tabular form for side-by-side comparison.

Summary – Neostigmine vs Pyridostigmine

Neostigmine and pyridostigmine are two oral acetylcholine esterase inhibitors. They are mainly used for the treatment of myasthenia gravis. Neostigmine is a more potent medication than pyridostigmine for the treatment of myasthenia gravis. So, this is the key difference between neostigmine and pyridostigmine

Reference:

1. “Neostigmine.” Uses, Interactions, Mechanism of Action | DrugBank Online.
2. “Pyridostigmine Uses, Side Effects & Warnings.” Drugs.com.

Image Courtesy:

1. “Neostigmine ball-and-stick” By MarinaVladivostok – Own work (CC0) via Commons Wikimedia
2. “Pyridostigmine synthesis” By Nuklear – Own work (CC BY-SA 3.0) via Commons Wikimedia