Drug class · FAERS comparison

Osmotic Laxative side effects compared: 5 drugs, 65,163 FDA adverse event reports

Class as assigned in the FDA label (Established Pharmacologic Class) · data 2026-09-14

How to read this page. Report counts are not incidence rates: a drug with more reports is usually older, more widely used or more publicised, not more dangerous. Signals are screened against each product's FDA label on its own page; a term flagged across most of a class usually reflects the shared mechanism or the shared patient population.

Members

Drug	FAERS reports	Serious	Death outcome	Boxed warning	Top labeled signals	Unlabeled (unassessed)
Lactulose (Generlac)	38,109	88%	6,655	–	–	–
Instalax Polyethylene Glycol 3350 (Polyethylene Glycol 3350)	12,332	54%	1,195	–	–	–
Polyethylene Glycol	10,759	83%	1,374	–	–	–
Polyethylene Glycol 3350 (Purelax)	3,191	75%	263	–	–	–
Polyethylene Glycol-3350 and Electrolytes	772	31%	23	–	–	Anhedonia

Class-wide signals (flagged in at least 3 of 5 members)

Reaction	Members flagged	Median PRR	Reports (sum)	In label
End stage renal disease	3/5	21.1	256	0/3 members' labels

Member-specific signals (flagged in exactly one drug)

Reaction	Drug	Reports	PRR	Label screen
Heart sounds	Lactulose	53	668.0	No label text to screen
Total lung capacity increased	Lactulose	96	299.0	No label text to screen
Prolonged expiration	Lactulose	54	141.4	No label text to screen
Asthma-chronic obstructive pulmonary disease overlap syndrome	Lactulose	97	126.1	No label text to screen
Aplastic anaemia	Polyethylene Glycol	204	78.9	No label text to screen
Female genital tract fistula	Instalax Polyethylene Glycol 3350	70	72.0	No label text to screen
Chronic hepatic failure	Lactulose	59	54.7	No label text to screen
Chronic sinusitis	Instalax Polyethylene Glycol 3350	116	54.3	No label text to screen
Hepatic encephalopathy	Lactulose	839	54.3	No label text to screen
Proctitis	Instalax Polyethylene Glycol 3350	76	47.3	No label text to screen
Radiculopathy	Instalax Polyethylene Glycol 3350	69	45.7	No label text to screen
Hyperparathyroidism secondary	Polyethylene Glycol	57	44.9	No label text to screen
Nephrogenic anaemia	Polyethylene Glycol	105	44.8	No label text to screen
Iron deficiency	Instalax Polyethylene Glycol 3350	109	42.7	No label text to screen
Appendicitis	Instalax Polyethylene Glycol 3350	210	39.3	No label text to screen
Infective pulmonary exacerbation of cystic fibrosis	Polyethylene Glycol	92	33.2	No label text to screen
Jaundice cholestatic	Lactulose	186	30.5	No label text to screen
Hypomania	Lactulose	173	27.0	No label text to screen
Orthostatic hypotension	Lactulose	803	26.5	No label text to screen
Varices oesophageal	Lactulose	138	26.3	No label text to screen
Febrile neutropenia	Polyethylene Glycol	854	25.4	No label text to screen
Streptococcal sepsis	Lactulose	51	24.5	No label text to screen
Hepatorenal syndrome	Lactulose	67	22.6	No label text to screen
Oesophageal varices haemorrhage	Lactulose	83	21.8	No label text to screen
Faecaloma	Lactulose	191	20.0	No label text to screen

Common questions

Which osmotic laxative has the most FDA adverse event reports?

Lactulose has the most FAERS co-reports in this class (38,109), followed by Instalax Polyethylene Glycol 3350 (12,332). Report volume tracks how widely and how long a drug has been used, and how much attention it has had, far more than its risk.

Which side effects are shared across osmotic laxative drugs?

Reaction terms flagged in at least half of the 5 members include end stage renal disease. A term shared across a class usually reflects the shared mechanism (or the shared patient population) rather than one product.

Does a FAERS signal mean the drug causes the reaction?

No. These are disproportionality signals from voluntary reports with no denominator. Each is screened against the FDA label (known vs unlabeled) on the drug pages; causality needs temporality, dose-response, plausibility and trial or cohort evidence.

Sources: openFDA FAERS pair statistics (OpenPV build 2026-09-14), FDA labels via openFDA, seriousness and death counts from openFDA count queries. Generated 2026-10-08. Not medical advice.