Antiparasitic agents are usually well-tolerated by patients who use them. Side effects that do occur tend to be minor, such as skin irritation. Patients who experience significant irritation should wash off the medication with soap and water and discontinue treatment.

Thiabendazole – the drug used to treat “creeping eruption” – may cause nausea, vomiting or diarrhea when it is prescribed in oral formulation. Other symptoms associated with thiabendazole include impaired mental alertness, low blood pressure (hypotension), skin rash, itchiness (pruritus), loss of appetite (anorexia) and unusual smelling urine (e.g., asparagus-like). Hallucinations, irritability, drowsiness, numbness or tingling in the hands or feet, dryness in the eyes or mouth and ringing or buzzing in the ears may also occur.

The scabies medication lindane has been associated with episodes in which the central nervous system is affected, causing seizures. Though rare, such incidences have resulted in some expert recommendations that lindane no longer be used to treat scabies.

Other side effects sometimes associated with various other antiparasitic agents include dizziness, redness, burning or swelling of the skin, skin rash, numbness, diarrhea, nausea, pruritus, worsened asthma, rapid heart rate (tachycardia), fever and headache.

Individuals experiencing severe or persistent side effects should contact their physician. Patients should contact their physician immediately if any of the following symptoms occur:

• Muscle and joint aches
• Blurred vision
• Chills
• Seizures
• Dark urine
• Pain or burning during urination
• Fever
• Lower back pain
• Weakness
• Unusual tiredness
• Jaundice (yellowing of the eyes and skin)
• Changes in the skin (e.g., blistering, peeling, loosening)