What are the possible side effects of M-Phen (Codeine/Phenylephrine/Promethazine)?
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Stop using this medication and call your doctor at once if you have any of these serious side effects: restless muscle movements in your eyes, tongue, jaw, or neck, tremor (uncontrolled shaking) weak or shallow breathing, feeling like you might pass out fast, slow, or pounding heartbeats confusion, agitation, hallucinations, nightmares, seizure (convulsions) jaundice (yellowing of the skin or eyes) easy bruising or bleeding, weakness urinating less than usual or not at all; or fever, stiff muscles, confusion, sweating, fast or uneven heartbeats, rapid breathing Less serious side effects may include: dizziness, drowsiness, sleepiness feeling restless, nervous, or anxious blurred vision, ringing in your ears constipation, mild nausea or vomiting warmth, redness, or tingly feeling under your skin itching, increased sweating; or sle
