CONTRIBUTOR(S): Vetstream Ltd, Julien Bazelle,
Medication: Pyridostigmine
Your cat has been prescribed pyridostigmine for the treatment of myasthenia gravis.
ℹ️Key points: • Anticholinesterase. • This drug is not licensed for use in cats. Your veterinarian will advise you as to off-license use of this medication. • Contact your veterinarian straight away if you accidentally overdose your pet with this medication as overdose of this medication may be fatal. • Dosage: two to three times daily.
ℹ️This information sheet is designed to help answer commonly asked questions and help you give the medication safely and effectively to your pet. It does not contain all available information for this medication. If you have other questions or need more information, contact your veterinarian or pharmacist. ⚠️Always follow the dosing instructions provided by your veterinarian.Name, Brand names, Class of medication and Storage
Name
- Pyridostigmine (pih-rid-o-stig-meen).
Brand name
- There are no licensed veterinary products containing pyridostigmine.
- Mestinon® (UK).
Class of medication
- Anticholinesterase.
Storage
- Store at room temperature.
Why has my cat been prescribed pyridostigmine?
Your veterinarian has prescribed pyridostigmine for the treatment of myasthenia gravis. Myasthenia gravis (MG) literally translates as “muscle weakness”. It is an unusual cause of generalized weakness in cats. Each muscle in the body is controlled by its own nerve, but this nerve does not connect directly to the muscle. At the junction between the nerve and the muscle there is a small gap. Signals travel along the nerve as an electrical current. When the electrical nerve impulse reaches the end of the nerve, the signal must be conveyed across the gap to the muscle. A chemical messenger called acetylcholine bridges this gap. This messenger is released from the end of the nerve, flows across the gap and fixes itself to a specific receptor (acetylcholine receptor) on the muscle. The acetylcholine attaches to the receptor (like a key fitting a lock) and triggers a signal, which causes the muscle to contract. In myasthenia gravis there is abnormal transmission of the message between the nerves and the muscles. This is either because the animal was born with too few acetylcholine receptors, or because the animal’s immune system has started attacking and destroying its acetylcholine receptors. If muscles are unable to contract properly, they become weak. Muscle weakness can affect the limbs so that animals are unable to stand or exercise normally but can also affect other muscles in the body. The muscles of the esophagus (the pipe carrying food from the mouth to the stomach) are often weak in cats with myasthenia gravis and this means that affected animals may have problems swallowing and often bring back food after eating. Pyridostigmine increases the amount of acetylcholine at the nerve receptor junctions and so improves efficacy of nerve transmission to muscles.
How is the medication given?
Pyridostigmine is given orally (as tablets). It is usually administered two to three times daily but follow your veterinarian’s dosing instructions. Tablets can either be administered directly into your pet’s mouth or given with food.
Are there any side-effects or drug interactions?
Possible side-effects of pyridostigmine include vomiting, nausea, diarrhea, drooling, sweating, fecal incontinence, small pupils, flickering eyes, slow heart rate, respiratory difficulties, low blood pressure and inappropriate urination. Your pet may be able to continue with the drug if side-effects are mild, but it’s best to let your veterinarian know as soon as possible if you have any concerns, so that they can decide whether additional medications or different medications are required. The following drugs may interact with pyridostigmine; atropine, clindamycin, lincomycin, polymyxins, propranolol, suxamethonium, corticosteroids, magnesium and muscle relaxants.
How long will my cat need to receive this medication?
Pyridostigmine should be administered according to your veterinarian’s instructions. The length of treatment will vary between patients.
How should I dispose of this medication if I don’t use it all?
Dispose of any unused pyridostigmine safely – do not flush down the toilet or sink. Ask your veterinary team if they take back medication for disposal. Do not save pyridostigmine for future use or give to other pets.
What if I miss a dose or give an extra dose?
If you miss a dose, give the dose as soon as possible but do not give a double dose. Make sure the dose given does not exceed the total recommended dose in any 24-hour period. If you accidentally double dose your pet with pyridostigmine, call your veterinarian immediately and ask for an immediate emergency appointment, as overdose of this medication can be fatal.
My cat is unwell, should I still give the drug?
If your pet is unwell, contact your veterinarian for advice.
What should I do if this medication is accidentally given to another pet or taken by a human?
Pyridostigmine should only be given to the cat that it has been prescribed for. If accidentally given to other pets, contact your veterinarian for advice. If accidentally consumed by a human, speak to your primary care physician or poison control center.
Will my cat need to be monitored while on pyridostigmine?
No specific tests are required while your cat is taking pyridostigmine, but your veterinarian will need to check your pet regularly to ensure that the drug is working safely and to comply with prescribing regulations.
Further information
If you have any concerns, further information on pyridostigmine can be found on the package insert or via your veterinarian.Europe & UK
- There are no licensed veterinary products containing this drug in the UK or Europe. Your veterinarian may prescribe a human medication containing this drug and will explain off-license use of medications to you.
- Mestinon® (Mestinon 60 mg Tablets – Summary of Product Characteristics: https://www.medicines.org.uk/emc/product/962/smpc)
US
- There are no licensed veterinary products containing this drug in the US. Your veterinarian may prescribe a human medication containing this drug and will explain off-license use of medications to you.