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warnings
WARNINGS Application of lidocaine 2.5% and prilocaine 2.5% cream to larger areas or for longer times than those recommended could result in sufficient absorption of lidocaine and prilocaine resulting in serious adverse effects (see Individualization of Dose ). Patients treated with class III anti-arrhythmic drugs (eg, amiodarone, bretylium, sotalol, dofetilide) should be under close surveillance and ECG monitoring considered, because cardiac effects may be additive. Studies in laboratory animals (guinea pigs) have shown that lidocaine 2.5% and prilocaine 2.5% cream has an ototoxic effect when instilled into the middle ear. In these same studies, animals exposed to lidocaine 2.5% and prilocaine 2.5% cream only in the external auditory canal, showed no abnormality. lidocaine 2.5% and prilocaine 2.5% cream should not be used in any clinical situation when its penetration or migration beyond the tympanic membrane into the middle ear is possible. Methemoglobinemia Lidocaine 2.5% and prilocaine 2.5% cream should not be used in those rare patients with congenital or idiopathic methemoglobinemia and in infants under the age of twelve months who are receiving treatment with methemoglobin-inducing agents. Very young patients or patients with glucose-6-phosphate dehydrogenase deficiencies are more susceptible to methemoglobinemia. Patients taking drugs associated with drug-induced methemoglobinemia such as sulfonamides, acetaminophen, acetanilid, aniline dyes, benzocaine, chloroquine, dapsone, naphthalene, nitrates and nitrites, nitrofurantoin, nitroglycerin, nitroprusside, pamaquine, paraaminosalicylic acid, phenacetin, phenobarbital, phenytoin, primaquine, quinine, are also at greater risk for developing methemoglobinemia. There have been reports of significant methemoglobinemia (20-30%) in infants and children following excessive applications of lidocaine 2.5% and prilocaine 2.5% cream. These cases involved the use of large doses, larger than recommended areas of application, or infants under the age of 3 months who did not have fully mature enzyme systems. In addition, a few of these cases involved the concomitant administration of methemoglobin-inducing agents. Most patients recovered spontaneously after removal of the cream. Treatment with IV methylene blue may be effective if required. Physicians are cautioned to make sure that parents or other caregivers und...
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adverse reactions
ADVERSE REACTIONS To report SUSPECTED ADVERSE REACTIONS, contact Hi-Tech Pharmacal Co., Inc. at 1-800-262-9010 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. Localized Reactions: During or immediately after treatment with lidocaine 2.5% and prilocaine 2.5% cream on intact skin, the skin at the site of treatment may develop erythema or edema or may be the locus of abnormal sensation. Rare cases of discrete purpuric or petechial reactions at the application site have been reported. Rare cases of hyperpigmentation following the use of lidocaine 2.5% and prilocaine 2.5% cream have been reported. The relationship to lidocaine 2.5% and prilocaine 2.5% cream or the underlying procedure has not been established. In clinical studies on intact skin involving over 1,300 lidocaine 2.5% and prilocaine 2.5% cream-treated subjects, one or more such local reactions were noted in 56% of patients, and were generally mild and transient, resolving spontaneously within 1 or 2 hours. There were no serious reactions that were ascribed to lidocaine 2.5% and prilocaine 2.5% cream. Two recent reports describe blistering on the foreskin in neonates about to undergo circumcision. Both neonates received 1.0 g of lidocaine 2.5% and prilocaine 2.5% cream. In patients treated with lidocaine 2.5% and prilocaine 2.5% cream on intact skin, local effects observed in the trials included: paleness (pallor or blanching) 37%, redness (erythema) 30%, alterations in temperature sensations 7%, edema 6%, itching 2% and rash, less than 1%. In clinical studies on genital mucous membranes involving 378 lidocaine 2.5% and prilocaine 2.5% cream-treated patients, one or more application site reactions, usually mild and transient, were noted in 41% of patients. The most common application site reactions were redness (21%), burning sensation (17%) and edema (10%). Allergic Reactions: Allergic and anaphylactoid reactions associated with lidocaine or prilocaine can occur. They are characterized by urticaria, angioedema, bronchospasm, and shock. If they occur they should be managed by conventional means. The detection of sensitivity by skin testing is of doubtful value. Systemic (Dose Related) Reactions: Systemic adverse reactions following appropriate use of lidocaine 2.5% and prilocaine 2.5% cream are unlikely due to the small dose absorbed (see Pharmacokinetics subsection of CLINICAL PHARMACOLOGY ). Sys...