Tubocurarine has ganglionic and neuromuscular blocking action and it is responsible for death by paralysis of the respiratory muscles and asphyxiation in cases of poisoning by curare.
In the form of chloride it is used in anesthesiology to procure the relaxation of the skeletal musculature during surgical interventions and to facilitate tracheal intubation for mechanical ventilation, as well as in the treatment of tetanus, eclampsia, spastic disorders, and serious cases of convulsions in particular.
What is Tubocurarine?
Tubocurarine is a drug that belongs to the group of muscle relaxants, and more precisely of the "competitive non-depolarizing neuromuscular blocking agents."
Also known as "competitive neuromuscular blockers", the competitive non-depolarizing neuromuscular blocking drugs act on the peripheral nervous system, interrupting the neuromuscular transmission by competing with the activity of the neurotransmitter acetylcholine, and thereby reducing the response of acetylcholine receptors issued subsequently to the nervous impulse.
D-tubocurarine is the principal alkaloid of curare (generic name with which crude extracts obtained are indicated from the bark of the roots of plants of the genus Strychnos and Chondrodendron), used for centuries by some indigenous tribes of South America as a paralyzing poison. Dipping the arrows in this poison, can lead to death to a prey by paralysis of skeletal muscles and cessation of breathing.
The major physiological effects of curare are due to the action of the alkaloid D-tubocurarine and similar alkaloids. Tubocurarine is considered the founder of the non-depolarizing muscle relaxants group, which also includes Rocuronium, Alcuronium, gallamine triethiodide, Metocurine, Pancuronium, Atracurium, Cisatracurium, Vecuronium.
How should Tubocurarine be taken?
Tubocurarine is available in the form of preparations for injections.
Side effects associated with Tubocurarine
There are several adverse effects that may result from the use of this drug:
- General disorders: allergic reactions, excessive release of histamine;
- Cardiovascular disturbances: hypotension, reflex tachycardia;
- Respiratory disorders: dyspnea, bronchospasm, laryngospasm, asthma;
- Musculo-skeletal disorders: muscle weakness;
- Dermatologic disorders: rash, urticaria, reactions at the injection site.
Contraindications and warnings associated with the use of Tubocurarine
Particular care should be taken when administering this drug to patients with known or suspected hypersensitivity to the product. Moreover, this drug should only be administered by experienced staff.
Similar to all other neuromuscular blocking agents, the dosage of Tubocurarine should be individualized for each patient.
Certain conditions – mostly due to severe electrolyte disturbances, altered blood pH or dehydration – can increase the effects of this drug: hypokalemia, hypermagnesemia, hypocalcaemia, hypoproteinaemia, dehydration, acidosis, hypercapnia, cachexia.
It is important for medical personnel to gather all necessary information about concomitant medications taken by the patient before administration of the drug, In fact, some drugs may increase the effects; while concomitant use of other substances tends to reduce efficacy.
Finally, the administration of other non-depolarizing neuromuscular blocking agents in combination with Tubocurarine can produce attenuation or enhancement of the neuromuscular block, depending on the order of administration and the neuromuscular blocking agent used.
Particular caution in administration of this drug is required in cases of pregnancy or breastfeeding, which must always be preceded by the treating physician.
