Certain flea medications should NOT be used in pets with Myasthenia Gravis: Do not use products containing: DEET Permethrin – contained in Advantix, Bio-Spot, etc. Methocarbamol (Robaxin), a muscle relaxer, should not be used in pets with MG. pyrantal pamoate (Strongid, Nemex), an anthelmintic (de-wormer)

Drugs that should NEVER be used by patients with myasthenia gravis: * D-Penicillamine (Cuprimin, Depen)

Drugs that should be used with caution by patients with myasthenia gravis: Certain Antibiotics * Erythromycin (A/T/S, Akne-Mycin, E-Mycin, E.E.S, Emgel, ERY, Erycette, EryDerm, Erygel, Erymax, EryPed, Ery-Tab, Erythrocin, Erythrostatin, Ilosone, Ilotycin, PCE, Staticin, T-Stat;, Theramycin Z) * Gentamicin (Garamycin) * Kanamycin * Neomycin (Mycifradin, Myciguent;, NeoTab) * Streptomycin * Tobramycin (Nebcin;, TOBI;, Tobrex) * Fluoroquinolones: Ciprofloxacin (Cipro, Ciloxan) Cardiovascular drugs * Quinidine (Cardioquin, Quinidex;Quinaglute) * Procainamide (Procan, Procanbid, Pronestyl) * Calcium channel blockers * Beta-blockers: * Atenolol (Tenormin) * Nadolol (Corgard) * Propranolol (Betachron, Inderal) * Timolol (Betimol, Blocadren, Timoptic) Muscle relaxants * Succinylcholine (Anectine, Quelicin;, Sucostrin) * d-tubocurarine * Any other neuromuscular blocking agent Narcotics * Meperidine (Demerol) * Morphine Other medications * Iodinated contrast agents * Magnesium Preparations — Magnesium aluminum hydroxide (Maalox) * Quinine.

Drugs that Compromise Neuromuscular Transmission per Dr. Diane Shelton of the Neuromuscular Lab at Univ. of California, Davis: Example: Fluroquinalones ARE contraindicated in cases of MG, however, after a long discussion on the VIN (Veterinary Information Network) with neurology, internal medicine and pharmacology experts, the conclusion regarding the fluroquinalones is that if a dog w/ MG is dying and a fluroquinalone is the only option, we use that drug. Yes, there are risks. 60,000 people per year die of aspirin, some w/ “just an idiosyncratic reaction,” some w/ OD, etc., yet aspirin is still used. Additionally, cortisone (pred) can actually excacerbate symptoms of MG, and that is frequently used. Every day veterinarians and physicians weigh the risks and benefits of using drugs. Chemotherapy drugs frequently cause other cancers, yet we still use those drugs. Unfortunately, although there are a lot of different antibiotics, there are none that are the same as the fluroquinalones. And, in general, fluro’s are in a price range that most can afford. Ticaracillin, Vancomycin, and several other injectable and oral drugs can’t “compete” w/ the fluro’s, so we do not to frighten folks against using these drugs, but, they must be used cautiously. Below, I am listing all of the drugs that have been advised NOT to use w/ dogs w/ MG. Note: penicillins are contraindicated. That means that we should ideally not use ampicillin, amoxicillin, cephalexin, clavamox, etc., as they are all “penicillins.” Drugs that Compromise Neuromuscular Transmission per Dr. Diane Shelton of the Neuromuscular Lab at Univ. of California, Davis.

Type of drug Drugs Anesthetics General anesthetics: benzodiazepines, ketamine, propanediol ether, proparacaine, methoxyflurane and others Local anesthetics: lidocaine, procaine, and others Neuromuscular blocking drugs: vecuronium, atracurium, succinylcholine, and others Antibiotics Aminoglycosides: gentamycin, tobramycin, kanamycin, neomycin, streptomycin, netilmicin Fluoroquinolones: ciprofloxacin, norfloxacin, pefloxacin, prulifloxacin (Rossi et al 2009) Ketolides: telithromycin (Perrot et al 2006) Macrolides: erythromycin, azithromycin, clarithromycin Polypeptide antibiotics: vancomycin, colistin, polymyxin B Penicillins Tetracyclines Sulfonamides Others: clindamycin, nitrofurantoin, ritonavir Anticonvulsants Phenytoin, mephenytoin, trimethadione, ethosuximide, barbiturates, carbamazepine, gabapentin, benzodiazepines Anti-rheumatics Chloroquine Cardiovascular drugs Beta-blockers: propranolol, oxprenolol, timolol, practolol, atenolol Calcium channel blockers: verapamil Others: quinidine, quinine, procainamide, bretylium, trimetaphan Ophthalmic medications Timolol, betaxolol, echothiophate Hormonal medications Corticosteroids (can have early exacerbations with high-dose therapy), estrogen Neurologic drugs Trihexyphenidyl, riluzole, botulinum toxin Psychiatric drugs Phenothiazines, lithium Others Statins (Purvin et al 2006), D-L-carnitine, tropicamide, iodinated radiographic contrast, magnesium sulfate.