Botulinum Toxin

"More and more experimental and clinical studies are being conducted to determine future applications of botulinum toxin, such as in hyperhidrosis (excessive sweating) and sialorrhea (excessive saliva formation)".


Botulinum toxin is a neurotoxin produced by a bacterium called Clostridium botulinum.

The ingestion of food contaminated by preformed botulinum toxin produces botulism, a disease characterized by the development of vegetative disorders (dry mouth, nausea and vomiting) and progressive muscular paralysis.

This capacity that the botulinum toxin possesses to produce muscular paralysis is used from the clinical point of view to treat certain neurological illnesses that occur with muscular hyperactivity.

Its use has spread not only in the medical field, but also in other areas such as aesthetics. Neurology is one of the medical specialties in which botulinum toxin provides the greatest therapeutic benefits.

Although there are numerous neurological entities potentially treatable with botulinum toxin, its most frequent use is limited to certain diseases characterized by involuntary movements, especially in the case of dystonia.

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When is botulinum toxin indicated?

Local infiltration of botulinum toxin is considered the treatment of choice and most effective for most focal dystonias. These types of dystonias are characterized by affecting a single muscle or a muscle group and are the most common during adulthood.

On the contrary, the treatment of generalized dystonia (idiopathic torsion dystonia) is mainly pharmacological (anticholinergics, benzodiazepines, neuroleptics).

Blepharospasm, or intermittent or persistent contraction of the orbicularis oculi muscles, was the first focal dystonia treated with local infiltration of botulinum toxin. Other types of dystonias that benefit dramatically from this treatment are cervical dystonia (spasmodic torticollis) and certain limb dystonias called occupational (scribe's cramp). The therapeutic benefit in the case of oromandibular and laryngeal dystonias is usually more discreet.

Other neurological disorders that can be treated with local infiltration of botulinum toxin are hemifacial spasm, certain tremors, and stiffness or spasticity.

Most frequent indications for this treatment:

  • Blepharospasm.
  • Dystonia.
  • Torticollis.
  • Spasticity after a stroke.

The pharmacological effect of botulinum toxin takes place at the level of the neuromuscular junction.

In this transition region between the peripheral nerve and the muscle, acetylcholine is released, a neurotransmitter necessary to produce muscle contraction.

Botulinum toxin acts locally by blocking the release of acetylcholine, resulting in temporary muscle paralysis. The final effect is a temporary chemodenervation at the neuromuscular junction without producing any physical injury to the nerve structures.

Do you have any of these diseases?

You may need to be treated with botulinum toxin

How is the botulinum toxin treatment performed?

¿Cómo se aplica la toxina botulínica?

The technique of application of the botulinum toxin varies between the different working groups. The most important initial measure for its application is the identification by palpation of the painful areas and the hyperactive muscles responsible for the dystonic posture.

It can be very helpful to ask the patient to identify the most painful spots.

In the case of obese patients or complex dystonic postures, it is convenient to identify the muscles involved by means of electromyographic recording.

There is no standardized dose of botulinum toxin for the treatment of dystonias. The clinical benefit is usually observed during the first week and the duration of the effect ranges from 2-4 months.

With successive treatments, the dose of botulinum toxin and the injection points are individualized for each patient according to the results obtained initially. The recommended frequency for successive infiltrations should not be less than 3-4 months.

Posibles efectos secundarios de la toxina botulínica

Local infiltration of botulinum toxin in focal dystonias, especially in blepharospasm, spasmodic torticollis and scribe cramp, is considered a safe and effective treatment.

Excessive muscle weakness is the most frequent adverse effect that appears in this type of treatment.

In the case of blepharospasm, the weakness is manifested by the fall, sometimes complete, of the upper eyelids

In the case of cervical dystonia, difficulty in swallowing (dysphagia), cervical muscle weakness and local pain at the injection site are the most frequent side effects.

The incidence of adverse effects related to botulinum toxin infiltration is dose-dependent. In general, these side effects are mild and transitory and do not limit the performance of successive infiltrations.

Where do we do it?


The Department of Neurology
of the Clínica Universidad de Navarra

The Neurology Department has extensive experience in the diagnosis and multidisciplinary treatment of neurological diseases.

We offer a diagnosis in less than 72 hours, along with a proposal for personalized treatment and post-consultation follow-up of the patient by our specialized nursing team.

We have the most advanced technology for an accurate diagnosis with cutting-edge equipment such as HIFU, deep brain stimulation devices, video EEG, PET and epilepsy surgery, among others.

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Why at the Clinica?

  • State-of-the-art diagnostic assistance with great work in research and teaching.
  • Specialized nursing team.
  • We work together with the Sleep Unit.

Our team of professionals

Especialistas en Neurología con experiencia en el tratamiento con toxina botulínica