Lithium is typically taken two or three times per day, with food, at consistent times. The standard starting dose for adults is 300 mg three times daily, though your prescriber will adjust this based on blood tests that measure exactly how much lithium is in your system. Because lithium has a narrow window between an effective dose and a toxic one, how you take it matters as much as how much you take.
Standard Doses and How They’re Adjusted
Most adults start at 300 mg three times a day. From there, the dose is gradually increased based on blood work. For acute manic episodes, the usual dose lands around 600 mg two to three times daily. For long-term maintenance (preventing future episodes), the range is broader: 300 to 600 mg, two to three times daily.
Your prescriber isn’t guessing. They’re targeting a specific concentration of lithium in your blood. During an acute episode, the goal is typically 0.8 to 1.2 mEq/L. For maintenance, a lower range of 0.6 to 0.99 mEq/L is effective for most people. Older adults often do best at even lower levels, between 0.4 and 0.8 mEq/L. Research has confirmed that levels above 0.4 mEq/L significantly reduce the recurrence of major mood episodes in stable patients.
Immediate-Release vs. Extended-Release
Lithium comes in two main formulations, and they’re taken differently. Immediate-release capsules or tablets are usually taken two to three times a day. They’re absorbed quickly, which means your blood levels spike after each dose and then drop before the next one. Extended-release tablets are designed to smooth out those peaks and valleys. They can often be taken just once or twice daily.
A two-year comparative study found that extended-release users maintained steadier blood concentrations (between 0.65 and 0.69 mEq/L) compared to immediate-release users, whose levels fluctuated more widely (0.52 to 0.61 mEq/L). That stability is likely why extended-release formulations tend to cause fewer side effects. If you’re on the extended-release version, swallow the tablet whole. Crushing or chewing it defeats the slow-release design and can cause a dangerous surge in absorption.
Lithium also comes as an oral solution, which is useful for people who have difficulty swallowing pills. The liquid form is dosed at 5 mL three times daily as a starting point.
When and How to Take Each Dose
Take lithium with food or a full glass of water. This reduces the nausea and stomach irritation that are common, especially early in treatment. Try to take your doses at the same times each day. Consistency helps keep your blood levels stable, which is the entire point of the dosing schedule.
If you miss a dose, take it as soon as you remember, unless it’s nearly time for your next dose. In that case, skip the missed one and continue your regular schedule. Never double up to make up for a forgotten dose. Doubling creates a temporary spike in blood levels that can push you toward toxicity.
Hydration and Salt Intake
Your kidneys handle lithium the same way they handle sodium (salt). When you’re dehydrated or your sodium levels drop, your kidneys hold on to more lithium instead of filtering it out. This causes lithium levels to rise, sometimes dangerously.
Drink plenty of water throughout the day, especially in hot weather or during exercise. Aim for steady, adequate hydration rather than forcing excessive amounts. Keep your salt intake consistent from day to day. This isn’t the time to start a low-sodium diet without telling your prescriber. Anything that causes heavy fluid loss (intense workouts, stomach bugs with vomiting or diarrhea, saunas) can concentrate lithium in your blood and trigger toxicity.
Blood Tests You’ll Need
Lithium requires more monitoring than most medications. After starting or changing your dose, expect a blood draw 5 to 7 days later. That timing matters because it takes about five days for lithium levels to stabilize after any change. The blood sample is typically drawn 12 hours after your last dose (usually first thing in the morning, before your morning dose).
Once your levels are stable, monitoring shifts to a longer-term schedule. Kidney function, thyroid function, and calcium levels should be checked every 6 months. Lithium can affect how your kidneys filter waste and how your thyroid produces hormones, so these tests catch problems early. If any results come back abnormal, testing becomes more frequent.
Medications That Interfere With Lithium
Several common medications can raise lithium to dangerous levels in your blood. The most important ones to know about:
- NSAIDs like ibuprofen and naproxen reduce how efficiently your kidneys clear lithium. Even occasional use can bump your levels up. Acetaminophen (Tylenol) is generally a safer choice for pain relief.
- Certain blood pressure medications, particularly ACE inhibitors and a class of diuretics called thiazides, can significantly increase lithium retention.
- Some antidepressants, including SSRIs, can both raise lithium concentrations and increase the risk of a condition called serotonin syndrome when combined with lithium.
Other medications with documented interactions include certain antibiotics (metronidazole, tetracyclines), the anti-seizure drug topiramate, and the anti-seizure/mood stabilizer carbamazepine. Always mention that you take lithium when any provider prescribes something new, including dentists and urgent care doctors.
Recognizing Lithium Toxicity
Because the gap between a therapeutic dose and a toxic one is small, you need to recognize the warning signs. Early symptoms of toxicity overlap with common side effects but are more intense: nausea, vomiting, diarrhea, stomach pain, a noticeable hand tremor, dizziness, and feeling unusually weak. These symptoms often appear when blood levels climb above 1.5 mEq/L.
More severe toxicity affects the nervous system. Signs include slurred speech, lack of coordination (stumbling, difficulty with fine motor tasks), uncontrolled eye movements, muscle twitching, confusion, and seizures. At its worst, lithium toxicity can lead to coma and kidney failure.
People who have been on lithium for a long time can develop chronic toxicity even at levels that used to be fine for them. This looks different: increased reflexes, persistent tremors, memory problems, increased thirst, and changes in urination. If you notice any combination of these symptoms, especially after an illness that caused dehydration or after starting a new medication, treat it as urgent. Stop taking lithium and get medical attention quickly.
Habits That Keep Lithium Working Safely
The people who do best on lithium tend to build a few simple habits. Take it at the same times every day, ideally anchored to meals. Keep a water bottle with you. Don’t make sudden changes to your diet, especially salt intake. Show up for blood draws on schedule, even when things feel stable. Let every prescriber know you’re on lithium before accepting a new medication, and check with your pharmacist before taking over-the-counter pain relievers. These small, consistent steps are what keep lithium in the narrow range where it works well without causing harm.