Cimetidine is generally well tolerated for short courses, but gastrointestinal upset and headache are common. Longer courses or higher doses can unmask endocrine and neurologic adverse effects, especially when renal function is impaired.
Monitor for GI changes during the first week, review medication lists for CYP interactions, and reassess chronic therapy to avoid endocrine or neuropsychiatric adverse effects.
2 documented effects
Not specified
Encourage hydration, bland diet; call if stools are watery, bloody, or accompanied by fever
Escalate if diarrhea lasts >48 hours or dehydration signs appear
Not specified
Offer small frequent meals; consider dosing with meals if tolerated
Assess for persistent pain or vomiting that limits intake
2 documented effects
Not specified
Hydration, rest; consider evening dosing
Evaluate if severe, persistent, or associated with visual changes
Not specified
Stop medication and contact clinician; assess renal function and medication interactions
Watch for sudden behavior changes, disorientation, or hallucinations
2 documented effects
Not specified
Discuss with prescriber; consider alternative acid suppression therapy
Monitor for galactorrhea or menstrual changes in adolescents
Not specified
Assess nutritional status; supplement B12 if deficiency suspected
Watch for fatigue, paresthesias, or anemia in chronic users
2 documented effects
Not specified
Discontinue and arrange urgent evaluation with CBC
Watch for fever, infections, unusual bruising, or bleeding
Not specified
Stop immediately; seek urgent care for anaphylaxis or swelling
Assess for rash, pruritus, wheezing, or facial swelling
2 documented effects
Not specified
Monitor liver function tests if symptoms develop; discontinue if significant elevations occur
Watch for jaundice, dark urine, or persistent nausea
Not specified
Slow infusion rate; monitor vitals; discontinue if symptomatic
Applicable in inpatient settings with IV use
For babies taking Cimetidine, watch for signs of side effects. This medication is generally well-tolerated in infants when used as directed.
This medicine calms tummy acid. Call us if there is bad diarrhea, a rash, or trouble waking up.
Tell us about stomach pain, headaches, or if you feel dizzy or confused after taking the medicine.
Report any breast tenderness, menstrual changes, or new medicines you start while on cimetidine.
A: This is common and usually improves within a few days. Keep fluids up and call if diarrhea becomes severe, lasts more than two days, or has blood.
When to validate: Escalate if dehydration signs, high fever, or blood in stool
A: Stop the medication and contact your clinician immediately. We will review dosing, kidney function, and other medicines.
When to validate: Same-day clinician evaluation
A: These rare effects should be reported promptly; an alternative acid reducer may be recommended.
When to validate: Schedule clinic visit for exam and medication review
Screen for neurologic and endocrine adverse effects
Parent and clinician concerns about Cimetidine