2020.1 SAQ 14 Adverse effects of neostigmine

This photo was not taken by me. I found it at The Toxicologist Today. It is a photo of the beautiful Amanita muscaria which will produce many, but not all, of the same side effects as neostigmine.

Describe the adverse effects of neostigmine.

Another drug we use on a daily basis (at least where I work as sugammadex is deemed too expensive for routine reversal).

Over 15 yrs ago, (but still seared on my brain) I made one of the 3 drug errors I know of. I gave a baby a 5x excess dose of neostigmine having mistakenly drawn up my calculated volume from the adult rather than baby sized ampoule. One side effect was prominent. What do you think it would have been? It responded very quickly to atropine, which I assumed I had forgotten to give. It was only on inspection of my ampoules once the situation had resolved that I discovered my mistake…

You will find decent information on this topic in any pharmacology text.

BT_GS 1.40 Describe the adverse effects of anticholinesterase agents 

Neostigmine will slow the breakdown of ACh throughout the body T/F

Neostigmine will produce weakness via actions at the NMJ regardless of the dose used T/F

Bradycardia is main effect of neostigmine on the cardiovascular system T/F

Neostigmine is highly lipid soluble, so seizures are likely to occur when large doses are given T/F

Neostigmine may cause diarrhoea T/F

Patents taking neostigmine have an increased risk of acute angle glaucoma T/F

There is another post on this material here if you want some more practice.

BT_GS 1.40 Describe the adverse effects of anticholinesterase agents

Anticholinesterase agents come in many forms, some you encounter in the operating theatre and some in the Emergency Department or the community (farms and a particular English park)

This post does not completely address the BT_GS 1.40 so I would suggest you read about the effects of organophosphates and nerve agents. These compounds are not mentioned in the curriculum document but you might encounter patients in the Emergency Department at some stage in your career.

The questions come from these references: Miller 8e Ch 35 and Ch 16 and Evers, Maze,  Kharasch 2e Ch 39 (both available on the ANZCA Library website)

T/F Administration of neostigmine in the absence of a non-depolarising neuromuscular blocking agent can cause muscle weakness

T/F the onset of action of these pairs of drugs are well matched:  edrophonium/atropine   neostigmine/glycopyrrolate

T/F neostigmine has a ceiling effect on acetylcholinesterase

T/F neostigmine is safe to administer even if the cisatracurium has worn off

T/F neostigmine binds covalently to acetylcholinesterase

T/F the duration of action of neostigmine is affected by renal failure*

T/F the duration of action of neostigmine is affected by hypothermia*

*Based on your answers to these questions, what would be the implications for clinical practice? (Hint: how do these situations affect muscle relaxants)

The following are anticholinesterases. Each is different to the others – see if you can work out how? (NB This is not all strictly examinable but may help your understanding)

• edrophonium, neostigmine, and pyridostigmine, physostigmine, pralidoxime

 

The following questions are not examinable 😀 and the answers are not in the references mentioned above:

T/F Novichok is the name of a thrash metal band

T/F Novichok is the name of an anticholinesterase compound

 

2018.1 SAQ 12 Neostigmine and sugammadex

Compare and contrast the pharmacology of neostigmine and sugammadex

“Anaesthesia reversal”, as these drugs are referred to on an automated theatre record we used to use, has always stuck me as a funny term – I hope I never have an anaesthetic where either of these two drugs is sufficient to reverse it! These are drugs we give on a daily basis, although sugammadex is used rarely in the institution I work in because of the cost. Is that its only limitation?

You should find these drugs covered adequately in the  pharmacology books on the reading list

BT_GS 1.39 Describe the reversal of neuromuscular blockade using anti- cholinesterase agents, anticholinergics and sugammadex and the physiological effects of reversal

Both neostigmine and sugammadex will reverse all aminosteriod non depolarising muscle relaxants T/F

Sugammadex can be used safely in patients with severe renal impairment (eGFR < 30ml/min) T/F

Unlike neostigmine, sugammadex has no effect on acetylcholine T/F

In a patient with a TOF ratio ≥ 2, equipotent doses of sugammadex and neostigmine with have a similar time to onset of effect T/F

There is a significant risk of oral contraceptive pill failure in patients who have received sugammadex T/F