Are Dizziness, Headache And Bad Taste Side Effects Of Metronidazole?

hey my partner is taking dihydrocodeine 30 mg and metronidazole 400mg for a tooth problem and he has been having some side effects which are he is feeling dizzy ,sick and hes got a horible taste in his mouth also he has been getting head aches and he has just been sick i would just like some advice on what is best to do about it