Tab A to Z frequency
The A to Z frequency of the alphabet in standard English (i.e., how often each letter appears in typical English text):
| Letter | Frequency (%) |
|---|---|
| A | 8.17 |
| B | 1.49 |
| C | 2.78 |
| D | 4.25 |
| E | 12.70 |
| F | 2.23 |
| G | 2.02 |
| H | 6.09 |
| I | 6.97 |
| J | 0.15 |
| K | 0.77 |
| L | 4.03 |
| M | 2.41 |
| N | 6.75 |
| O | 7.51 |
| P | 1.93 |
| Q | 0.10 |
| R | 5.99 |
| S | 6.33 |
| T | 9.06 |
| U | 2.76 |
| V | 0.98 |
| W | 2.36 |
| X | 0.15 |
| Y | 1.97 |
| Z | 0.07 |
Key takeaways:
- E is the most frequent letter (~12.7%), followed by T, A, O, I, N
- Z, Q, and J are the rarest (all under 0.15%)
- The top 6 letters (E, T, A, O, I, N) account for roughly half of all letter occurrences in English
These figures are based on analysis of large English text corpora (Oxford English Dictionary / Corpus of Contemporary American English). Exact percentages vary slightly depending on the corpus used.
Od or bd
Reading File
OD vs BD are Latin prescription abbreviations for dosing frequency:
| Abbreviation | Latin | Meaning | Doses/Day | Interval |
|---|---|---|---|---|
| OD | Omni die | Once daily | 1 | Every 24 hours |
| BD (= BID) | Bis in die | Twice daily | 2 | Every 12 hours |
When to use which?
OD (Once Daily) is preferred when:
- The drug has a long half-life (e.g., amlodipine, atorvastatin, levothyroxine)
- A sustained-release / extended-release formulation is used
- Better compliance is the goal (once-daily regimens have higher adherence)
- The drug's therapeutic window is wide and peak-trough fluctuation is acceptable
BD (Twice Daily) is preferred when:
- The drug has a shorter half-life and needs more consistent plasma levels
- Splitting the dose reduces side effects (e.g., metformin - GI tolerance is better with BD)
- The drug requires tighter concentration control (e.g., some antibiotics, antiepileptics)
Common examples
| Drug | Frequency | Reason |
|---|---|---|
| Amlodipine | OD | Long half-life (~35-50 hrs) |
| Atorvastatin | OD (night) | Peak hepatic synthesis at night |
| Metformin 500mg | BD | Short half-life, GI side effect reduction |
| Amoxicillin | BD or TDS | Time-dependent killing, MIC maintenance |
| Metoprolol succinate (XR) | OD | Extended release |
| Metoprolol tartrate | BD | Immediate release, shorter half-life |
Bottom line: OD is better for compliance; BD is better when pharmacokinetics demand more frequent dosing to maintain therapeutic plasma levels. If you're asking about a specific drug, I can give a more targeted answer.
Tab A to Z od or bd
A to Z list of common drugs (tablets) with their dosing frequency — OD or BD (or other where applicable):
| Letter | Drug | Frequency | Notes |
|---|---|---|---|
| A | Amlodipine | OD | Long half-life ~35-50 hrs |
| B | Bisoprolol | OD | Once daily beta-blocker |
| C | Cetirizine | OD | Antihistamine, long acting |
| D | Doxycycline | OD or BD | Usually OD for most infections |
| E | Escitalopram | OD | SSRI, once daily |
| F | Furosemide | OD or BD | Usually OD; BD in resistant oedema |
| G | Glimepiride | OD | With breakfast |
| H | Hydrochlorothiazide | OD | Morning dose |
| I | Irbesartan | OD | ARB, long acting |
| J | Januvia (Sitagliptin) | OD | DPP-4 inhibitor |
| K | Ketoconazole (tab) | OD | Antifungal |
| L | Losartan | OD | ARB; some use BD for BP control |
| M | Metformin 500mg | BD | Short half-life; GI tolerance better split |
| N | Nebivolol | OD | Once daily beta-blocker |
| O | Olmesartan | OD | ARB, long acting |
| P | Pantoprazole | OD | PPI, before breakfast |
| Q | Quetiapine IR | BD | IR form needs splitting; XR is OD |
| R | Rosuvastatin | OD | Statin, any time of day |
| S | Sertraline | OD | SSRI, once daily |
| T | Telmisartan | OD | Longest acting ARB (~24 hr) |
| U | Ursodeoxycholic acid | BD or TDS | Often split doses |
| V | Valsartan | OD or BD | Usually OD |
| W | Warfarin | OD | Fixed evening dose |
| X | Xarelto (Rivaroxaban) | OD or BD | OD for AF/VTE prevention; BD (15mg) in acute DVT/PE phase |
| Y | Yaz (Ethinylestradiol/ Drospirenone) | OD | OCP, same time daily |
| Z | Zolpidem | OD (at night) | Hypnotic, single bedtime dose |
Key patterns to remember:
- Most ARBs, statins, SSRIs, beta-blockers (long-acting), CCBs → OD
- Metformin IR, short-acting beta-blockers, IR antipsychotics → BD
- PPIs → OD (before first meal), sometimes BD in GERD/H. pylori regimens
- XR/SR/ER formulations of any drug are almost always OD vs their IR counterpart being BD/TDS
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