Sorry for the delay in responding - I was on vacation over the weekend.
Lipitor can cause IBS-like symtpoms, including both consitpation and diarrhea (both in less than 3% of cases). Here is a complete rundown of reported side-effects:
ADVERSE REACTIONS SIGNIFICANT
>10%: Central nervous system: Headache (3% to 17%)
2% to 10%:
Cardiovascular: Chest pain, peripheral edema
Central nervous system: Weakness (0% to 4%), insomnia, dizziness
Dermatologic: Rash (1% to 4%)
Gastrointestinal: Abdominal pain (0% to 4%), constipation (0% to 3%), diarrhea (0% to 4%), dyspepsia (1% to 3%), flatulence (1% to 3%), nausea
Genitourinary: Urinary tract infection
Neuromuscular & skeletal: Arthralgia (0% to 5%), myalgia (0% to 6%), back pain (0% to 4%), arthritis
Respiratory: Sinusitis (0% to 6%), pharyngitis (0% to 3%), bronchitis, rhinitis
Miscellaneous: Infection (2% to 10%), flu-like syndrome (0% to 3%), allergic reaction (0% to 3%)
<2% (Limited to important or life-threatening): Alopecia, anaphylaxis, angina, angioneurotic edema, arrhythmia, bullous rashes, cholestatic jaundice, deafness, dyspnea, erythema multiforme, esophagitis, facial paralysis, glaucoma gout, hepatitis, hyperkinesias, impotence, migraine, myasthenia, myopathy, myositis, nephritis, pancreatitis, paresthesia, peripheral neuropathy, petechiae, photosensitivity, postural hypotension, pruritus, rectal hemorrhage, rhabdomyolysis, somnolence, Stevens-Johnson syndrome, syncope, tendinous contracture, thrombocytopenia, tinnitus, torticollis, toxic epidermal necrolysis, urticaria, vaginal hemorrhage, vomiting
I am not aware of a direct connection with irritable bowel syndrome.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
Medical Weblog:
kevinmd_b