Prilocaine

Source: eMC SPC for Prilocaine hydrochloride 1% Solution for Injection. Elderly/debilitated patients require smaller doses, commensurate with age and physical status. Care should be taken to prevent toxic reactions by avoiding intravascular injection — great caution is needed since accidental intravascular injection may cause rapid onset of toxicity with marked restlessness, twitching or convulsions, followed by coma with apnoea and cardiovascular collapse. Regional anaesthetic procedures should always be performed in a properly equipped and staffed area with resuscitation equipment and drugs immediately available; when performing major blocks an i.v. cannula should be inserted before the local anaesthetic is injected. Methaemoglobinaemia is the specific hazard of prilocaine: it may occur at lower doses in patients with anaemia, congenital or acquired haemoglobinopathy (including methaemoglobinaemia) or in patients on concomitant therapy known to cause it (e.g. sulphonamides); infants are particularly susceptible due to lower activity of the enzyme that reduces methaemoglobin, and patients with cardiac insufficiency require special attention. Not approved for post-operative intra-articular continuous infusion of local anaesthetics — there have been post-marketing reports of chondrolysis with this use. Possibly porphyrinogenic: only prescribe to patients with acute porphyria when no safer alternative is available. Peribulbar injections carry a low risk of persistent ocular muscle dysfunction, and injections in the head and neck regions may be made inadvertently into an artery causing cerebral symptoms even at low doses. Paediatric restriction (SPC 4.2): prilocaine hydrochloride should not be used in children under 6 months of age, and should not be used for paracervical (PCB) block or pudendal block in the obstetric patient; there is an increased risk of methaemoglobin formation in children and in the neonate after delivery. The openFDA and WHO providers returned no content for this id.

dosePerKg left null because the SPC states only a per-kg ceiling, not a per-kg dose to administer. Verbatim source (SPC 4.2): 'Prilocaine hydrochloride should not be used in children under 6 months of age and for use in paracervical (PCB) block and pudendal block in the obstetric patient. There is an increased risk of methaemoglobin formation in children and in the neonate after delivery. In children above the age of 6 months the dosage can be calculated on a weight basis up to 5 mg/kg.' Infants are particularly susceptible to methaemoglobinaemia due to lower activity of the enzyme that reduces methaemoglobin (SPC 4.4). Verify against a children's formulary before prescribing.