Metformin (Metformin Hydrochloride) - Side Effects and Adverse Reactions

ADVERSE REACTIONS

In a U.S. double-blind clinical study of metformin in patients with type 2 diabetes, a total of 141 patients received metformin therapy (up to 2550 mg per day) and 145 patients received placebo. Adverse reactions reported in greater than 5% of the metformin patients, and that were more common in metformin- than placebo-treated patients, are listed in Table 7.

Table 7. Most Common Adverse Reactions (>5%) in a Placebo-Controlled Clinical Study of Metformin Monotherapy* 

Adverse Reaction	Metformin Monotherapy (n=141)	Placebo (n=145)
	% of patients
* Reactions that were more common in metformin- than placebo-treated patients.
Diarrhea	53.2	11.7
Nausea/Vomiting	25.5	8.3
Flatulence	12.1	5.5
Asthenia	9.2	5.5
Indigestion	7.1	4.1
Abdominal Discomfort	6.4	4.8
Headache	5.7	4.8

Diarrhea led to discontinuation of study medication in 6% of patients treated with metformin. Additionally, the following adverse reactions were reported in ≥1 to ≤5% of metformin patients and were more commonly reported with metformin than placebo: abnormal stools, hypoglycemia, myalgia, lightheaded, dyspnea, nail disorder, rash, sweating increased, taste disorder, chest discomfort, chills, flu syndrome, flushing, palpitation.

Pediatric Patients

In clinical trials with metformin in pediatric patients with type 2 diabetes, the profile of adverse reactions was similar to that observed in adults.

REPORTS OF SIDE EFFECTS / ADVERSE REACTIONS RELATED TO METFORMIN

Possible Metformin side effects / adverse reactions in 73 year old male

Reported by a health professional (non-physician/pharmacist) from Sweden on 2007-01-12

Patient: 73 year old male

Reactions: Gastrointestinal Haemorrhage, Syncope, Anaemia, Blood Creatinine Increased

Adverse event resulted in: hospitalization

Suspect drug(s):
Atacand HCT
    Administration route: Oral
    Indication: Essential Hypertension

Lasix
    Administration route: Oral

Trombyl 160 MG
    Administration route: Oral

Metformin
    Administration route: Oral
    Indication: Diabetes Mellitus

Glibenklamid Recip 1,75 MG
    Administration route: Oral
    Indication: Diabetes Mellitus

Diclofenac Sodium
    Indication: Gout

Other drugs received by patient: Folacin 5 MG; Behepan 1 MG; Lansoprazole

Possible Metformin side effects / adverse reactions in male

Reported by a physician from France on 2007-02-26

Patient: male weighing 92.0 kg (202.4 pounds)

Reactions: Myalgia, Abdominal Pain, Vomiting, Cytolytic Hepatitis, Jaundice Cholestatic, Pyrexia

Suspect drug(s):
Crestor
    Administration route: Oral
    Indication: Hypercholesterolaemia
    Start date: 2005-11-18
    End date: 2006-07-29

Allopurinol Sodium
    Indication: Gout
    Start date: 1998-01-01
    End date: 2006-07-29

Metformin
    Indication: Diabetes Mellitus non-Insulin-Dependent
    Start date: 2005-09-01
    End date: 2006-07-29

Other drugs received by patient: Cokenzen; Sectral; Kardegic

Possible Metformin side effects / adverse reactions in 81 year old female

Reported by a individual with unspecified qualification from Norway on 2007-03-05

Patient: 81 year old female

Reactions: Lactic Acidosis, Renal Failure Acute

Suspect drug(s):
Glimepiride
    Administration route: Oral

Calcium Channel Blockers
    Dosage: dose: unk

Hydrochlorothiazide
    Dosage: dose: unk

Lisinopril

Metformin