Skip to main content
. 2021 Oct 30;27(4):495–512. doi: 10.5056/jnm20210

Table 1.

Characteristics of Studies Comparing Laxative With Placebo or Comparing Laxatives of Same Types

Study, country Comparison Design Eligible population Constipation criteria Intervention and duration Number of patients and mean age Primary outcome Results
Bulk laxatives
Ewerth et al18 (1980), Sweden Bulk vs Placebo Double-blind cross-over study Constipated patients with diverticuli Infrequent (3-4 day interval) and painful defecation

  • A: Psyllium 6 g bid

  • B: Placebo

  • 8 wk for each (4-wk washout)

  • 9 (F 6)

  • Mean age 68 (range 62-77) yr

  1. Transit time

  2. BMs/wk

  3. Abdominal symptoms

  1. No significant difference

  2. A: 6.9 B: 7.1 (NS)

  3. Symptoms improved with psylliuma
Finlay19 (1988), UK Bulk vs Placebo Open, randomized, placebo-controlled, parallel study Elderly patients with chronic constipation in continuing care Chronic constipation with need for regular laxative, suppositories and/or manual evacuation

  • A: Bran 1.5-4.5 g qd

  • B: Regular diet

  • 6 wk

  • A: 6 (F 6)

  • B: 6 (F 6)

  • Mean age 80 ± 5 yr

  1. Stool consistency

  2. Bowel frequency

  3. Suppository usage

  • 1. Significantly improved with treatment

  • 2. BMs/wk

  • A: 2.83 ± 0.91

  • B: 2.25 ± 0.82 (NS)

  • SBMs/wk

  • A: 2.63 ± 1.10

  • B: 0.02 ± 1.92a

  • 3. No difference for laxative use
Rajala et al20 (1988), Finland Bulk vs Placebo Randomized, double-blind study Hospitalized elderly patients Defecation less than once daily and with difficulty

  • A: Yoghurt + Bran, 150 mL bid

  • B: Yoghurt bid

  • 2 wk

  • A: 18

  • B: 15

  • Mean age 78 yr

  1. BMs/wk

  2. Abdominal pain and overall symptoms

  3. Need for laxatives

  1. A: 5.8 B: 4.5

  2. Abdominal pain and overall symptoms improved in group A

  3. Need for laxative: A: 1.3 B: 1.7
Cheskin et al21 (1995), USA Bulk vs Placebo Single-blind, randomized, placebo-controlled, crossover study Community-living older men and women with chronic constipation < 3 BMs/wk and/or feeling of incomplete evacuation and/or hard stool with straining > 25% of time

  • A: Psyllium 6 g qid

  • B: Placebo

  • 4 wk for each

  1. (F 5, M 5)

  2. Mean age 66 (range 66-87) yr

  1. Total gut transit time

  2. BMs/wk

  3. Consistency

  1. A: 30.0 hr B: 53.9 hra

  2. A: 9.1 B: 5.6

  3. Consistency did not improve significantly
Chokhavatia et al22 (1988), USA Bulk vs Bulk Unblinded, randomized study Outpatients age range 55-81 yr Regular laxative use

  • A: Calcium polycarbophil 2 g qd

  • B: Psyllium 9.5 g qd

  • 3 wk

  • 42

  • Age range 55-81 yr

  1. BMs/wk

  2. Consistency

  3. Preference

  1. A: 8.3 B: 9.1

  2. Consistency score was significantly high in A

  3. More patients preferred A as it produced less gasa
Osmotic laxatives
Wesselius-De Casparis et al23 (1968), Netherland Osmotic vs Placebo Multicenter, randomized, double-blind, placebo-controlled, parallel study Elderly patients with chronic constipation Regular laxative use

  • A: lactulose syrup 15 mL qd

  • B: Placebo

  • 3 wk

  • A: 54

  • B: 49

  • Mean age > 60 yr

 Treatment success if the patient needed no laxatives at all or only once in 21 day A: 86% B: 60%a
Sanders24 (1978), USA Osmotic vs Placebo Randomized, double-blind, placebo-controlled, parallel study Elderly constipated patients living in nursing home ≤ 3 BM/wk and ≥ 1 constipation related symptom

  • A: lactulose syrup 30 mL qd

  • B: Placebo

  • 12 wk

  • A: 20 (F 17)

  • B: 25 (F 22)

  • Mean age

  • 84.7 yr in A

  • 86.8 yr in B

  1. BM/wk

  2. Reduction in symptoms

  1. A: 4.9 B: 3.6a

  2. Significantly improved with lactulosea
Vanderdonckt et al25 (1990), Belgium Osmotic vs Placebo Double-blind, cross-over study Elderly patients with chronic constipation ≤ 3 BMs per wk without laxative use and ≥ 1 symptom such as hard stools, pain

  • A: Lactitol 20 g qd

  • B: Placebo

  • 4 wk for each

  • 46

  • Mean age 84 yr

  1. BMs/wk

  2. Consistency

  3. Need for laxatives

  1. BMs/wk increased with lactitolc

  2. Consistency improved with lactitolc

  3. Less need for rectally administered laxativesa
Dipalma et al26 (2007), USA Osmotic vs Placebo Double-blind, placebo-controlled, parallel study Adults and elderly who met defined criteria for chronic constipation Modified Rome criteria

  • A: PEG 3350 17 g qd

  • B: Placebo

  • 6 mo

  • A: 204 (F 175)

  • B: 100 (F 83) (elderly: 75)

  • Mean age of elderly were not specified

 Relief of modified Rome criteria for constipation for 50% or more

  • Total: A 61.4% B 21.8%b

  • Elderly patients: A 56% vs B 11%b
Lederle et al27 (1990), USA Osmotic vs Osmotic Randomized, double-blind, cross-over study Men aged 65 yr to 86 yr with chronic constipation ≤ 3 SBM/wk, ≤1 BM/day with current laxatives and at least one related chronic symptom such as straining, hard stool

  • A: Lactulose syrup 30-60 mL qd

  • B: Sorbitol 30-60 mL qd

  • 4 wk for each(2-wk washout)

  • 30 (M 30)

  • Mean age 72 (range 65-86)

  1. BM/wk

  2. Number of day/wk with BM

  3. Consistency

  1. A: 7.02 B: 6.71 (NS)

  2. A: 5.31 B: 5.23 (NS)

  3. 60% vs 67% of BM reported normal
Seinelä et al28 (2009), Finland Osmotic vs Osmotic Randomized, double-blind, parallel-group study Elderly institutionalized, constipated patients who have used PEG with electrolyte at a stable dose Regular use of PEG

  • A: PEG 4000 without electrolyte 12 g qd

  • B: PEG 4000 with electrolyte 12 g qd

  • 4 wk

  • A: 30 (F 18)

  • B: 32 (F 23)

  • Mean age

  • A: 86.4 yr

  • B: 84.8 yr

  1. BM/wk at week 4

  2. Proportion of normal stool consistency

  1. A: 8.5 ± 4.5B: 8.4 ± 3.6 (NS)

  2. A: 70% B: 52% (NS)
Chassagne et al29 (2017), France Osmotic vs Osmotic Randomized, single-blind, parallel-group study Patients aged 70 yr and older with a history of chronic constipation Rome I criteria

  • A: PEG 4000 10-30 g qd

  • B: Lactulose 10-30 g qd

  • 6 mo

  • A: 118 (F 90)

  • B: 127 (F 96)

  • Mean age

  • A: 82.7 ± 7.4 yr

  • B: 81.8 ± 7.9 yr

  1. BMs/wk

  2. Consistency

  3. AEs

  1. A:7.0-7.3 B:5.5-6.2a

  2. Improved consistency with PEG 4000

  3. See Table 4
Softener
Hyland and Foran30 (1968), UK Softener vs Placebo Randomized, double-blind, placebo-controlled, cross-over study Hospitalized elderly patients in geriatric ward Chronic constipation

  • A: DSS 100 mg tid

  • B: Placebo

  • 4 wk for each

  • 40

  • Mean age over 60 yr

  1. BMs/wk

  2. Overall symptom improvement

  1. A: 3.3 B: 2.5

  2. Symptom significantly improved with DSSa
Fain et al31 (1978), USA Softener vs Softener Randomized, single-blinded, parallel study Institutionalized elderly patients Chronic functional constipation dependent on laxative use

  • A: DSS 100 mg qd

  • B: DSS 100 mg bid

  • C: DCS 240 mg qd

  • Placebo 2 wk → treatment 3 wk for each

  • A: 13 (F 12)

  • B: 17 (F 15)

  • C: 16 (F 13)

  • Mean age

  • A: 83.4 yr

  • B: 82.2 yr

  • C: 80.8 yr

  1. BMs/wk

  2. Laxative use/ wk

  1. A: 1.50 ± 1.06 → 1.95 ± 1.79 B: 1.76 ± 1.26 → 2.29 ± 1.14 C: 1.75 ± 1.33 → 2.83 ± 1.73a

  2. A: 1.38 → 1.05 B: 1.03 → 0.92 C: 1.38 → 0.85a

aP < 0.05, bP < 0.01, cP < 0.001.

F, female; M, male; qd, once a day; bid, 2 times a day; tid, 3 times a day; qid, 4 times a day; BMs, bowel movements; NS, not significant; AEs, adverse effects; SBMs, spontaneous bowel movements; PEG, polyethylene glycol; DSS, dioctyl sodium sulfosuccinate; DCS, dioctly calcium sulfosuccinate.