Initial clinical experience with AH 8165D, a new rapidly acting nondepolarizing muscle relaxant

Clinical trial of fazadinium bromide (fazadon)

Fifty healthy Nigerian surgical patients were given fazadinium bromide at a dose level of 10 mg . kg-1 while 30 other similar patients received 1.5 mg . kg-1. Anaesthesia was induced with either thiopentone or alfathesin. Tracheal intubation was satisfactorily accomplished after a mean of 55 seconds with the 1 mg . kg-1 dose and a mean of 32 seconds with the 1.5 mg . kg-1 dose. Duration of action of fazadinium 1 mg . kg-1 was a mean of 42 min (range 30 to 50 min) while the mean for 1.5 mg . kg-1 was 55 min (range 45 to 70 min). There was no significant difference between the thiopentone and alfathesin induction groups. Reversibility with neostigmine was excellent. Whereas the 1 mg . kg-1 dose was satisfactory for normal regular intubation, the 1.5 mg . kg-1 dose is recommended for "crash" intubation. The administration of fazadinium was associated with a stable blood pressure and moderate sinus tachycerdia. No other side effects were seen.

Thiopentone and fazadinium crash induction. A comparison with thiopentone and pancuronium

A method of crash induction using fazadinium and thiopentone was studied in 100 patients not genuinely at risk from regurgitation. Speed and ease of intubation compared well with a previous study using pancuronium. Cardiovascular stability was not as good as with pancuronium and tachycardia was the major concern. Fourteen patients were assessed as 'difficult' to reverse and three recurarised.

The effect of thiopentone and fazadinium on intraocular pressure

Intraocular pressure was measured in twenty-four patients using an applanation tonometer, after using thiopentone and fazadinium as induction agents. No significant rise in intraocular pressure above resting levels was noted before or after tracheal intubation, and it is suggested that this combination of induction agents should be satisfactory for general anaesthesia of a patient with a perforating eye injury who presents with a full stomach.

Neuromuscular blockade of fazadinium bromide (AH 8165) in renal failure patients

Fazadinium bromide (AH 8165) is a new non-depolarizing neuromuscular blocking agent with rapid onset of action and intermediate duration of effect. The characteristics of the neuromuscular blockade induced were compared in normal and renal failure patients by monitoring the mechanical responses of thumb adductor muscle to ulnar nerve stimulation. The data suggest that renal failure, even in anephric patients, does not influence the depth of neuromuscular relaxation when judged from the identical dose-effect curves in both groups of patients. Moreover, the duration of the neuromuscular block was not significantly increased in end-stage kidney failure patients, whether the initial or late phases of the spontaneous recovery of neuromuscular transmission were considered, and this occurred over the entire therapeutic range. However, additional incremental injections of fazadinium bromide should be used cautiously, as evidence appeared of prolonged duration of action. This agent, fazadinium bromide, may therefore present useful advantages to other non-depolarizing neuromuscular blocking agents as to clinical safety and effects in patients with renal insufficiency.

Rapid intubation with fazadinium and suxamethonium

Fazadinium at two dose levels (1 mg/kg and 1.5 mg/kg) and suxamethonium at three dose levels (50 mg, 75 mg and 100 mg) were investigated in 106 adult patients to determine the time interval from injection to tracheal intubation. The intubating conditions were graded according to the scheme described by Lund and Stovner. Suxamethonium 100 mg gave the shortest time interval between the end of injection and intubation. There was no significant difference between the intubation time when smaller doses of suxamethonium (50 mg and 75 mg were used and those when AH8165 (1 mg and 1.5 mg/kg) were given. Suxamethonium 100 mg also produced a significantly higher incidence of excellent intubating conditions. The clinical implications of the findings are discussed.

Rapid intubation with fazadinium. A comparison of fazadinium with suxamethonium and alcuronium

The speed of onset and intubation conditions have been compared for suxamethonium 1 mg/kg, alcuronium 0-32 mg/kg and fazadinium 1 mg/kg and 1-25 mg/kg. Fazadinium 1 mg/kg was not significantly different in times to intubation from suxamethonium although the latter gave a highly significant greater number of patients with excellent conditions. The higher dose of 1-25 mg/kg fazadinium did not give significantly better intubating conditions than the lower dose. Although the times to intubation for the two dose levels of fazadinium did not differ statistically, the higher dose was significantly slower in onset than suxamethonium. Alcuronium was slower than either suxamethonium or fazadinium 1 mg/kg in producing satisfactory conditions. The nondepolarizing drug, fazadinium, may be a useful neuromuscular blocking agent in emergency cases where rapid intubation is required and when it is wished to avoid possible or probable adverse effects from the depolarising drug suxamethonium.

Human placental transfer of AH8165

The human placental transfer of AH8165 (0times50times9 mg/kg) was studied in ten patients undergoing elective Caesarean section. There was no adverse effect on foetal movement attributable to placental transfer of the neuromuscular blocking drug. Bioassay of umbilical vein blood indicated that little AH8165 crossed the placenta. Studies using 3HAH8165 in two patients undergoing termination hysterectomy demonstrated transfer of only minute amounts of radioactivity to the foetus.

Intubating conditions with AH 8165 and suxamethoniun

Intubating conditions after AH 8165, 1times25 mg/kg, have been compared with those after suxamethonium 1 mg/kg in 240 patients. Patients were matched for physical fitness and intubating conditions were studied in different groups at 30, 45, 60 and 75 seconds after the relaxant. At all times suxamethonium produced a higher incidence of good relaxation of the vocal cords and the incidence of excellent overall intubating conditions was significantly higher with suxamethonium. It proved impossible to intubate eleven patients with AH 8165 at the chosen time but all patients receiving suxamethonium could be intubated.