- 54% less likely to report headaches
- 64% less likely to report fatigue
- 68% less likely to report muscle pain
- Kuodi, P. et al. Preprint at medRxiv (2022).
- 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.
All commonly-used anaesthetic agents cause some degree of upper airway collapse, although dexmedetomidine probably has the least impact.
Van Decar et al. on the diagnosis and management of intra-operative diabetes insipidus concludes:
For the average adult patient, urine output >125 mL/h is consistent with polyuria. Urinary osmolality and specific gravity should be obtained and levels <300 mOsm/kg and <1.003, respectively, are consistent with hypotonic urine.
It is prudent to rule out other causes of polyuria including hyperglycemia, uremia, or iatrogenic causes including diuretic or mannitol administration.
Serum electrolytes and osmolality should also be obtained, and a high sodium (>146 mmol/L) and plasma osmolality (>300 mOsm/kg) are typically seen with DI.
Treatment should focus on replacement of free water deficit with a balanced salt solution, pharmacotherapy including DDAVP or vasopressin as appropriate, and close monitoring of patient’s fluid and electrolyte status.
Common anaesthetic agents, including propofol, dexmedetomidine, sevoflurane, ketamine & opioids, can rarely cause intraoperative diabetes insipidus.
Ultrasound-guided caudal injection does not improve overall success or block performance time compared to landmark caudal injection, but does improve first-puncture success and reduce complications.
Intrathecal opioids significantly prolong & benefit post-caesarean section analgesia.
3000+ double-Pfizer-vaccinated Israeli subjects, July and November 2021, several months after COVID infection when compared to unvaccinated counterparts:
In fact, prevalence of these long-covid symptoms was no different than among groups not infected with COVID.
Obesity increases the risk of NMBD anaphylaxis (OR 2.96).
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