The overactive reflexes and clonus in moderate cases may be greater in the lower limbs than in the upper limbs.

Signs of pyramidal system involvement, including spasticity, overactive reflexes (hyperreflexia) and extensor plantar reflexes, also occur.

Overdose symptoms may include agitation, hallucinations, fever, overactive reflexes, loss of coordination, extreme drowsiness, vomiting, diarrhea, seizure (convulsions), fast heart rate, feeling light-headed, or fainting.

Overdose symptoms may include irregular heartbeats, extreme drowsiness, overactive reflexes, stiff muscles, dilated pupils, vomiting, feeling hot or cold, feeling like you might pass out, or seizure (convulsions).

Call your doctor at once if you have a serious side effect such as numbness or tingly feeling around your mouth, fast or slow heart rate, muscle tightness or contraction, overactive reflexes, seizure, feeling short of breath, swelling, rapid weight gain, or feeling like you might pass out.