Prilocaine

There are no adequate data from the use of prilocaine in pregnant women. Prilocaine is able to cross the placenta. Cases of neonatal methaemoglobinaemia requiring treatment have been reported following paracervical block or pudendal anaesthesia with prilocaine during obstetric use. Cases of foetal bradycardia with fatalities have occurred with other local amide-type anaesthetics following paracervical block. Studies in animals have shown developmental toxicity.

Prilocaine may therefore only be administered in cases where there is a compelling indication for its use. Use of prilocaine for paracervical block or pudendal anaesthesia should be avoided.

Breast-feeding

It is not known whether prilocaine passes into breast milk. If administration is required during lactation, breast-feeding can be resumed approximately 24 hours after treatment.

Fertility

No human data on the effect of prilocaine on fertility are available. Prilocaine had no effect on the fertility of male and female rat.

In the case of using prilocaine, the doctor is responsible for deciding in each individual case if the patient can drive or use machines.

The possible undesirable effects due to the use of prilocaine are generally similar to the undesirable effects of other local anaesthetics for spinal anaesthesia from the amide group. The undesirable effects induced by the medicinal product are difficult to distinguish from the physiological effects of the nerve block (e.g. reduction in arterial pressure, bradycardia, temporary urine retention), from direct effects (e.g. spinal hematoma) or the indirect effects (e.g. meningitis) of the injection or from the effects due to the loss of cerebrospinal liquid (e.g. post-spinal headache).

The frequency of onset of undesirable effects is classified as follows: very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1000 to <1/100), rare (≥1/10000 to <1/1000), very rare (<1/10000).

Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness.

Blood and lymphatic system disorders

Rare: Methemoglobinemia, Cyanosis

Immune system disorders

Rare: Anaphylactic shock, Anaphylactic reactions, Allergic reactions, Itching

Nervous system Disorders

Common: Paresthesia, Dizziness

Uncommon: Signs and symptoms of CNS toxicity (convulsions, circumoral paresthesia, loss of consciousness, shaking, feeling of numbness affecting the tongue, speech problems, hearing problems, tinnitus, visual problems)

Rare: Arachnoiditis, Neuropathy, Lesions of peripheral nerves

Eye disorders

Rare: Diplopia

Cardiac disorders

Uncommon: Bradycardia

Rare: Cardiac arrest, Arrhythmia

Vascular disorders

Very common: Hypotension

Uncommon: Hypertension

Respiratory, thoracic and mediastinal disorders

Rare: Respiratory depression

Musculoskeletal and connective tissue disorders

Uncommon: Back pain, temporary muscle weakness

Gastrointestinal disorders

Very common: Nausea

Common: Vomiting

The signs of intoxication from local anaesthetics are similar for any injected preparation, both in the way in which they manifest, and in their treatment.

In spite of the demonstrated high clinical tolerability of prilocaine, undesirable toxic effects cannot be excluded in the presence of plasma levels above a critical threshold. These undesirable effects mainly manifest as symptoms affecting the central nervous and cardiovascular system.

The most effective prophylactic measures are scrupulous compliance with the recommended posology for prilocaine, with it being essential for the doctor to check its action (visual and verbal contact with the patient), as well as careful aspiration prior to injecting the solution.

Mild undesirable effects (feeling dizzy or dazed) can be attributed to moderate overdose and generally resolve rapidly after reducing the dose or halting administration of prilocaine.

Serious undesirable effects are attributable to significant overdose and/or accidental injection of local aesthetic into a blood vessel. They manifest as symptoms affecting the central nervous system (restlessness, speech problems, disorientation, dizziness, muscle contractions, cramps, vomiting, loss of consciousness, respiratory arrest and mydriasis) and the cardiocirculatory system (raised arterial pressure and pulse frequency, arrhythmia, drop in arterial pressure, asystole) following irritation and/or depression of the cerebral cortex and the cerebral marrow.

In addition, following inhibition or block of the cardiac conduction system, cardiac frequency may slow down and myocardial depression may occur.

Any problems relating to metabolism (liver) or excretion (kidney) of prilocaine should also be considered as other possible causes of undesirable effects.