What do systematic reviews say?

Oral vs intramuscular vitamin B12

• Oral vitamin B₁₂ versus intramuscular vitamin B₁₂ for vitamin B₁₂ deficiency 2018 · Cochrane Headline outcomes only
  no estimate extracted
  2 studies · 120 participants
  Very low

Oral vs vaginal administration of oestradiol and dydrogesterone

The review found no eligible studies for this question.

• Hormone therapy for uterine and endometrial development in women with premature ovarian insufficiency 2022 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Oral vs IV antibiotics

Oral showed no clear difference in adverse events requiring discontinuation of antibiotics compared with intravenous antibiotic therapy (low certainty).

• Oral versus intravenous antibiotic treatment for febrile neutropenia in cancer patients 2013 · Cochrane Headline outcomes only
  RR 1.45 [0.61, 3.46]
  15 studies · 1823 participants
  Low

Oral 5‐ASA vs SASP

Oral 5‐ASA probably leads to lower adverse events compared with SASP (moderate certainty).

• Oral 5‐aminosalicylic acid for induction of remission in ulcerative colitis 2020 · Cochrane Headline outcomes only
  RR 0.48 [0.36, 0.63]
  12 studies · 909 participants
  Moderate

Oral 5‐ASA vs 5‐aminosalicylic acid (5‐ASA) (mesalazine)

Oral 5‐ASA showed no clear difference in adverse events compared with comparator 5‐ASA (moderate certainty).

• Oral 5‐aminosalicylic acid for induction of remission in ulcerative colitis 2020 · Cochrane Headline outcomes only
  RR 1.01 [0.92, 1.12]
  9 studies · 1576 participants
  Moderate

Oral 5‐ASA vs placebo

Oral 5‐ASA showed no clear difference in adverse events compared with placebo (high certainty).

• Oral 5‐aminosalicylic acid for induction of remission in ulcerative colitis 2020 · Cochrane Headline outcomes only
  RR 0.95 [0.85, 1.07]
  8 studies · 1218 participants
  High

Oral tramadol vs oral morphine

• Tramadol with or without paracetamol (acetaminophen) for cancer pain 2017 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  Very low

Oral cryotherapy (ice chips, ice-cold water, ice cubes or crushed ice held in the mouth during cancer treatment) vs no intervention or control intervention (control)

• Interventions for preventing oral mucositis in patients with cancer receiving treatment: oral cryotherapy 2015 · Cochrane All outcomes

  High-dose melphalan-based treatment prior to HSCT (haematological cancers)
  Adverse events reported narratively: one study did not report adverse events (Askarifar 2015); another reported no serious adverse events (Toro 2013); the remaining two reported low rates of shooting pain from the…
  3 studies
  GRADE not reported
• Interventions for preventing oral mucositis in patients with cancer receiving treatment: oral cryotherapy 2015 · Cochrane All outcomes

  Fluorouracil (5FU) treatment for solid cancers
  Adverse events reported narratively (not meta-analysed): one study reported no adverse effects (Katranci 2012); the other four 5FU studies reported low rates of very minor adverse events (headache, chills,…
  5 studies · 444 participants
  GRADE not reported

Oral 5‐ASA vs SASP

Oral 5‐ASA showed no clear difference in serious adverse events compared with SASP (low certainty).

• Oral 5‐aminosalicylic acid for induction of remission in ulcerative colitis 2020 · Cochrane Headline outcomes only
  RR 1.36 [0.28, 6.52]
  2 studies · 107 participants
  Low

Oral 5‐ASA vs 5‐aminosalicylic acid (5‐ASA) (mesalazine)

Oral 5‐ASA showed no clear difference in serious adverse events compared with comparator 5‐ASA (low certainty).

• Oral 5‐aminosalicylic acid for induction of remission in ulcerative colitis 2020 · Cochrane Headline outcomes only
  RR 0.59 [0.22, 1.56]
  4 studies · 677 participants
  Low

Oral 5‐ASA vs placebo

Oral 5‐ASA showed no clear difference in serious adverse events compared with placebo (low certainty).

• Oral 5‐aminosalicylic acid for induction of remission in ulcerative colitis 2020 · Cochrane Headline outcomes only
  RR 0.53 [0.18, 1.56]
  4 studies · 746 participants
  Low

Oral beta‐estradiol vs conjugated equine estrogens

• Bioidentical hormones for women with vasomotor symptoms 2016 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 103 participants
  Very low

Oral tramadol vs oral morphine

• Tramadol with or without paracetamol (acetaminophen) for cancer pain 2017 · Cochrane Headline outcomes only
  no estimate extracted
  2 studies · 280 participants
  Very low

Oral 5‐ASA vs SASP

Oral 5‐ASA probably leads to lower withdrawal due to adverse events compared with SASP (moderate certainty).

• Oral 5‐aminosalicylic acid for induction of remission in ulcerative colitis 2020 · Cochrane Headline outcomes only
  RR 0.4 [0.24, 0.68]
  10 studies · 640 participants
  Moderate

Oral 5‐ASA vs 5‐aminosalicylic acid (5‐ASA) (mesalazine)

Oral 5‐ASA showed no clear difference in withdrawal due to adverse events compared with comparator 5‐ASA (moderate certainty).

• Oral 5‐aminosalicylic acid for induction of remission in ulcerative colitis 2020 · Cochrane Headline outcomes only
  RR 0.94 [0.57, 1.54]
  9 studies · 1489 participants
  Moderate

Oral 5‐ASA vs placebo

Oral 5‐ASA probably leads to lower withdrawal due to adverse events compared with placebo (moderate certainty).

• Oral 5‐aminosalicylic acid for induction of remission in ulcerative colitis 2020 · Cochrane Headline outcomes only
  RR 0.72 [0.54, 0.97]
  13 studies · 2372 participants
  Moderate

Oral ciclosporin vs azathioprine (AZA)

Oral ciclosporin showed no clear difference in adverse events: severe compared with oral azathioprine (low certainty).

• Interventions for cutaneous disease in systemic lupus erythematosus 2021 · Cochrane Headline outcomes only
  RR 0.89 [0.48, 1.65]
  1 study · 89 participants
  Low

Oral methotrexate vs oral chloroquine

Oral methotrexate may leads to higher adverse events: minor compared with oral chloroquine (low certainty).

• Interventions for cutaneous disease in systemic lupus erythematosus 2021 · Cochrane Headline outcomes only
  RR 3.9 [1.45, 10.51]
  1 study · 41 participants
  Low

Oral methotrexate vs oral chloroquine

Oral methotrexate showed no clear difference in adverse events: severe compared with oral chloroquine (low certainty).

• Interventions for cutaneous disease in systemic lupus erythematosus 2021 · Cochrane Headline outcomes only
  RR 1.73 [0.27, 11.07]
  1 study · 41 participants
  Low

Oral NSAIDs vs placebo

• Non‐steroidal anti‐inflammatory drugs (NSAIDs) for treating lateral elbow pain in adults 2013 · Cochrane Headline outcomes only
  no estimate extracted
  2 studies · 292 participants
  GRADE not reported