Prescription drugs such as viscous lidocaine should not be used to numb gums in teething babies, Food and Drug Administration has warned.

Teething is a normal part of growing up that can be treated without using prescription drugs, FDA said Thursday.

"Teething is a normal phenomenon; all babies teethe," said Ethan Hausman, M.D., a pediatrician and pathologist at FDA, according to a news release. "FDA does not recommend any sort of drug, herbal or homeopathic medication or therapy for teething in children."

Viscous lidocaine is given to patients undergoing chemotherapy (children and adults). The gel-like syrup relieves mouth ulcers that can occur due to chemotherapy. Dentists, too, use the drug to reduce gag reflex in children during dental X-rays.

Institute for Safe Medication Practices (ISMP) has recently received several reports of children being given the gel without a physician's consent. Common symptoms of an overdose of viscous lidocaine include jitteriness, confusion, vision problems and even seizures, FDA said.

The agency had earlier warned parents and caregivers against using gels containing benzocaine to relieve teething pain in babies.

Over-the-counter gels like Anbesol, Hurricaine, Orajel, Baby Orajel, and Orabase contain Benzocain. According to FDA, bezocain is a local anesthetic and its use can sometimes lead to a rare, but serious condition called methemoglobinemia, which is characterized by drop in oxygen levels in the blood. Children under two years of age are at high risk of suffering from this condition.

Infants with painful, tender gums can be given a teething ring or a wet, clean wash-towel.

"The cool object acts like a very mild local anesthetic," said Hari Cheryl Sachs, M.D., a pediatrician at FDA. "This is a great relief for children for a short time."

Parents should supervise children who are chewing on a teething ring or wash-cloth.