- pH 3.5
- Shelf life 3 years at 4°C, though only 'months' at 20°C.
- Dose - ED95 0.5 mg/kg, IV 1.5 mg/kg, IM 2.5-4 mg/kg.
- Absorption - IM, IV.
- Distribution - >0.2 L/kg; crosses placenta slightly but little effect on foetus.
- Protein binding ?
- Onset 30s IV, 2-3 min IM; Offset 3-5 min.
- Metabolism - PChE to succinylmonocholine (5% activity) & choline -> succinic acid & choline.
- tß½ 5 minutes
- Mechanism - binds to alpha subunit of nicotinic ACh receptor, producing persistent depolarisation (phase 1 & phase 2 blocks).
- CNS - ⇡ intra-ocular pressure (4-8 mmHg rise), ⇡ intra-celebral pressure (to 30 mmHg at 2-4 min).
- CVS - arrhythmias (both bradycardia & tachycardia possible), ⇡ systolic blood pressure, (both negative inotropic and chronotropic effects).
- Resp - 'sux apnoea' pharmacogenetic diversity (94% normal, 3.8% heterozyg (10 min duration of effect), <1% homozog (1-2h duration))
- Renal - hyperkalaemia due to K+ release from muscle; beware in neuromuscular conditions, denervation, and extensive burns.
- GIT - ⇡ intragastric pressure, ⇡ secretions, salivation.
- SEs - anaphylaxis, malignant hyperthermia, sux apnoea, muscle pains, masseter spasm.
Surgery should be delayed for at least 7 weeks after COVID, although those with persistent COVID symptoms will still have more than twice the 30-day mortality than those without. (COVID Surg Collaborative 2021)
After recovery from SARS-CoV-2 infection, minor surgery should be delayed 4 weeks and major surgery delayed 8-12 weeks. (Kovoor 2021)
Elective surgery should not be scheduled within 7 weeks of a SARS-CoV-2 infection. (El-Boghdadly 2021)
Pholcodine consumption greatly increases the risk of NMBD anaphylaxis (OR 14.0).
Sugammadex is pharmacologically great. A modified γ-cyclodextrin Selective Relaxant Binding Agent that reverses rocuronium muscle relaxation 10-times faster than neostigmine (see: Is sugammadex as good as we think?).
At launch, its biggest obvious disadvantage was simply the new drug's high cost. Now as sugammadex has become more widely used, sugammadex-anaphylaxis has risen as a new, prominent concern.
In Japan, where there was a uniquely rapid take-up of sugammadex, it became one of the commonest causes of anaphylaxis. Oriharia (2020) demonstrated an incidence of sugammadex anaphylaxis in Japan of 1 in 5,000 – a risk that most medically communities would consider too high for routine use of a drug with acceptable alternatives.
Given that in some regions (notably Australia & New Zeleand) rocuronium itself has a high-risk of anaphylaxis, the combination of rocuronium-sugammadex may present a greater risk than even old-school drugs such as suxamethonium.
In other countries, such as the United Kingdom, there has not been quite the same incidence of sugammadex-anaphylaxis. Is this simply because of the lower initial use than in Japan, or are there environmental and phenotypical differences as have been implicated for rocuronium anaphylaxis?
Worryingly, if the Japanese experience is representative, then for some locations the combination of rocuronium-sugammadex may in fact have a higher risk of anaphylaxis than using suxamethonium alone.
The true risk of sugammadex-anaphylaxis is still unclear for many populations. However with the looming expiry of the sugammadex patent in 2023, we will see a rapid increase in its use and subsequently reveal any latent anaphylaxis risk.
Suxamethonium chloride (suxamethonium, succinylcholine or sux) is a depolarising muscle relaxant that produces rapid-onset, short-duration, deep muscle relaxation. First identified in 1906 and used medically in 1951, it is one of the oldest anaesthesia drugs still widely used. Due to its unique properties and low cost, it remains on the World Health Organisation's List of Essential Medicines
In Japan, Sugammadex anaphylaxis occurs in ~1 in 5,000 exposures.
In 2020 the COVID Surg Collaborative demonstrated a shockingly-increased post-operative mortality among patients undergoing surgery during an active COVID infection.
This naturally led to questions regarding timing of elective surgery after COVID-19 recovery.
Although data is scant, the COVID Surg Collaborative again leads the way with a large multicenter study showing increased 30 day mortality even when surgery is delayed 5-6 weeks after COVID infection.
Various guidelines and recommendations exist, but summarising:
Several studies note that these periods are minimum recommended delays, and that patients with persisting symptoms still experience higher 30-day mortality even after delaying seven weeks. El-Boghdadly et al. suggests that this period should be used for functional prehabilitation for these patients.
Elective surgery should not be scheduled within 7 weeks of a SARS-CoV-2 infection.
After recovery from SARS-CoV-2 infection, minor surgery should be delayed 4 weeks and major surgery delayed 8-12 weeks.
Patients have increased postoperative risk when surgery occurs in the weeks after COVID recovery.
"...I encourage all patient safety stakeholders to resist an overemphasis on absolute safety, and instead draw on the strengths of both the safety I and safety II approaches. We should be clear about what types of harms can or cannot be prevented and anticipated, work to eliminate those where there is good evidence for preventability by adopting evidence-based practices, improve the ability of everyone responsible for safety to identify risks, conduct better risk analyses to anticipate and reduce unintended harms, measure and celebrate the routine adaptations that prevent harm, and reward organisational learning and improvement." – Thomas, 2020.
To improve overall safety and reduce harm, focus should be on reducing risk instead of eliminating harm.