What Is Lithium Carbonate Used For? Uses and Side Effects

Lithium carbonate is a simple salt of the metal lithium, and as a medicine it is one of the oldest and most trusted treatments for bipolar disorder. The same chemical goes into batteries and glass, but the pill form is about steadying mood. Its strength comes with a catch: the dose that helps sits close to the dose that harms, so taking it means living with regular blood tests.

What Lithium Carbonate Treats

Lithium is considered the gold-standard long-term treatment for preventing relapses of mania and depression in bipolar disorder.1PubMed Central. Facts and myths about the use of lithium for bipolar disorder in routine clinical practice: an expert consensus paper It has outperformed other treatments at preventing every type of mood episode, in both controlled trials and real-world use.2PubMed Central. Facts and myths about the use of lithium for bipolar disorder in routine clinical practice: an expert consensus paper In long-term trials, people on lithium had about a third fewer relapses of any kind than people on a dummy pill.3PubMed. Long-term lithium therapy for bipolar disorder: systematic review and meta-analysis of randomized controlled trials

Its main job is prevention, so you take it every day even when you feel well. It is not a quick fix for when symptoms flare. Effects on mania usually build over a week or more, and protection against new episodes over months. Stopping suddenly can bring a relapse, so any change is planned with the prescriber.

People sometimes expect to feel a clear effect after a pill, and the lack of one gets mistaken for the drug not working. Lithium doesn’t make you feel high, sedated or “different” the way some other psychiatric medicines can, so success often looks like fewer and milder episodes rather than a noticeable feeling.

No one knows exactly how it steadies mood. It seems to adjust signalling inside brain cells and help them adapt and survive.

Lithium can also be added to an antidepressant when depression hasn’t improved on the antidepressant alone.4Mental Health Clinician. A review of the evidence supporting the use of lithium augmentation therapy for the reduction of suicidal behavior in patients with unipolar depression: Revisiting an overlooked benefit of an older medication Across ten trials, about 1 in 5 people who got added lithium improved who would not have otherwise.5PubMed Central. Lithium in the episode and suicide prophylaxis and in augmenting strategies in patients with unipolar depression It also appears to lower suicidal thoughts and behaviour in people with depression.6Mental Health Clinician. A review of the evidence supporting the use of lithium augmentation therapy for the reduction of suicidal behavior in patients with unipolar depression: Revisiting an overlooked benefit of an older medication

Doctors sometimes use lithium to prevent cluster headaches, severe one-sided headaches that come in bouts.7PubMed. Double-blind placebo-controlled trial of lithium in episodic cluster headache This use lacks strong proof, and in one small open trial about half improved fully while a quarter didn’t respond.8PubMed. Double-blind placebo-controlled trial of lithium in episodic cluster headache

Common Side Effects

The most common complaints are thirst, frequent urination, dry mouth, weight gain, tiredness and trouble thinking clearly.9Revista de Psiquiatria ClĂ­nica. Lithium safety and tolerability in mood disorders: a critical review A fine shaking of the hands affects about a quarter of people taking lithium.10PubMed Central. Lithium side effects and toxicity: prevalence and management strategies This tremor is usually even on both sides and looks like ordinary shakiness.11PubMed Central. Lithium side effects and toxicity: prevalence and management strategies A tremor that suddenly gets worse, though, can be a warning of a level that’s too high.

Thirst and urination go together because lithium makes the kidneys less able to concentrate urine, so you pass more of it. The body then signals thirst to replace the water. Drinking to thirst is the right response, not cutting back on fluids.

Some of the other effects can be eased. Tremor often improves when doses are spread out or caffeine is cut. Weight gain is helped by choosing water rather than sugary drinks for thirst. Mental fog is worth mentioning to the prescriber, since a dose adjustment may help. Many effects are strongest in the first weeks and then settle.

Some symptoms are not routine side effects. Vomiting, diarrhoea, unsteady walking or confusion can mean the level has climbed, and they call for same-day medical advice.

Long-Term Effects on the Kidneys and Thyroid

Long-term lithium can harm the kidneys. It first shows as heavy urination and thirst, which can turn into lasting changes over years.12PubMed Central. Key questions on the long term renal effects of lithium: a review of pertinent data About a third of people on lithium for 10 to 29 years showed signs of chronic kidney weakness, but only about 5% were in the severe range.13PubMed. Effects of 10 to 30 years of lithium treatment on kidney function A smaller share see a drop in eGFR, the estimate of kidney filtering on blood test reports, and very few reach kidney failure.14PubMed Central. Key questions on the long term renal effects of lithium: a review of pertinent data In one group, kidney filtering fell about 3 points a year, reaching moderate kidney disease after about 15 years on average.15PubMed Central. Long-term lithium therapy and risk of chronic kidney disease, hyperparathyroidism and hypercalcemia: a cohort study

The risk grows with years and total dose, so monitoring matters most for long-term users. Catching a decline early lets the doctor lower the dose or switch.

Lithium can cause a goiter or an underactive thyroid, which causes tiredness, weight gain and feeling cold. Rarely it causes an overactive one.16PubMed. Effect of lithium carbonate on the function of the thyroid gland: mechanism of action and clinical implications In one small group treated 10 to 20 years, about 4 in 10 needed thyroid treatment.17PubMed. Hyperparathyroidism, hypothyroidism, and impaired renal function after 10 to 20 years of lithium treatment People with a parent, sibling or child with thyroid disease developed it after about 4 years, versus about 9 years for others.18PubMed Central. Effect of lithium maintenance therapy on thyroid and parathyroid function An underactive thyroid is usually managed with a daily thyroid pill, often without stopping lithium. Lithium can also raise blood calcium and overwork the parathyroid glands.19PubMed. Hyperparathyroidism, hypothyroidism, and impaired renal function after 10 to 20 years of lithium treatment20PubMed Central. Effect of lithium maintenance therapy on thyroid and parathyroid function

High calcium can cause thirst, constipation or low mood, which can be mistaken for side effects or depression, so blood tests sort them out.

Early kidney and thyroid changes usually cause no symptoms you would notice, so they are found through blood tests. Keep the routine tests even when you feel well.

Blood Tests and the Target Level

Levels are checked every 5 to 7 days when starting, then about every 6 months once levels are stable on long-term treatment.26PubMed Central. Retrospective analysis of lithium treatment: examination of blood levels Side effects can still occur within the target level.27PubMed Central. Retrospective analysis of lithium treatment: examination of blood levels Older adults need lower doses for the same level and can have toxic symptoms at levels that are normal for younger people.28Journal of IMAB – Annual Proceeding Scientific Papers. LITHIUM TOXICITY IN ELDERLY-A CASE REPORT AND DISCUSSION

For an accurate result, blood is usually drawn about 12 hours after the last dose, often in the morning. Taking the morning pill before the test gives a falsely high reading. Kidney and thyroid tests are often done at the same visit, and keeping a record of your results helps you spot trends.

Lithium comes as tablets, slow-release tablets and liquid lithium citrate. Switching brands or forms should prompt a new blood test.

What Can Push Lithium Levels Too High

The kidneys clear lithium, so drugs that change kidney handling change lithium levels.29PubMed Central. Lithium therapy and its interactions The most common culprits are anti-inflammatory painkillers such as ibuprofen, some blood pressure pills (ACE inhibitors and sartans), and water pills.30PubMed Central. Lithium therapy and its interactions Paracetamol (acetaminophen) is usually preferred over ibuprofen for pain. Tell every doctor and pharmacist you take lithium. A new blood pressure pill or water pill usually means an extra level check soon after.

The kidneys treat lithium much like sodium, reabsorbing it when the body is short of salt or water. So when you are dehydrated or low on salt, the blood level climbs even though your dose has not changed.

Cutting salt sharply makes the kidneys hold on to sodium and lithium, raising levels.31PubMed Central. Undetectable serum lithium concentrations after coadministration of liquid lithium citrate and apple juice: A case report32PubMed Central. Undetectable serum lithium concentrations after coadministration of liquid lithium citrate and apple juice: A case report A high-salt diet or very heavy drinking can lower levels.33PubMed Central. Undetectable serum lithium concentrations after coadministration of liquid lithium citrate and apple juice: A case report In one trial, a steady daily salt intake halved swings in lithium levels.34PubMed. Effect of regulated add-on sodium chloride intake on stabilization of serum lithium concentration in bipolar disorder: A randomized controlled trial So keep salt and fluid intake roughly the same from day to day.

Vomiting, diarrhoea or fever can dehydrate you quickly. Hot weather, saunas and hard exercise increase fluid loss. Starting a low-salt diet should be discussed with the prescriber first, and it’s worth asking what to do with your doses during a stomach bug.

Signs of Lithium Toxicity

Most lithium poisoning builds gradually and by accident, when intake outpaces what the kidneys clear.35PubMed. Lithium Poisoning Dehydration, illness or interacting drugs reduce kidney clearance.36PubMed. Lithium Poisoning The brain is affected first, with effects ranging from no symptoms through confusion and unsteady walking to seizures.37PubMed. Lithium Poisoning Deaths are rare, and lithium can be removed by dialysis in serious cases.38PubMed. Lithium Poisoning Slow-building poisoning can mean a long hospital stay, and lasting balance problems sometimes occur.39PubMed. Lithium Poisoning

Early signs include worse tremor, nausea, diarrhoea, drowsiness and slurred speech. Don’t take the next dose until you get advice. Contact the prescriber or go to emergency care the same day, and bring your pill bottle and latest level results.

One extra dose is usually not dangerous but should be reported. Don’t make up a missed dose by doubling. A large overdose is an emergency even without symptoms.

Pregnancy, Breastfeeding and Older Age

Lithium taken in the first three months raises the risk of birth defects, though less than once thought.40PubMed Central. Lithium during pregnancy and after delivery: a review One heart defect occurred in about 6 in 1,000 exposed babies versus about 2 in 1,000 unexposed.41PubMed Central. Lithium Use in Pregnancy and the Risk of Cardiac Malformations Risk was not clearly raised at 600 mg a day or less but was about three times higher above 900 mg.42PubMed Central. Lithium Use in Pregnancy and the Risk of Cardiac Malformations Other factors common in pregnancy with bipolar disorder may account for part of the risk.43PubMed. Epidemiology studies on effects of lithium salts in pregnancy are confounded by the inability to control for other potentially teratogenic factors

If you are pregnant or hoping to be, don’t stop suddenly, since relapse also carries risk. Talk with the prescriber before trying to conceive. Options include the lowest effective dose and extra baby heart scans. Heart defects can often be looked for with a detailed scan during pregnancy, which is part of the planning. Levels change in pregnancy and after birth, so tests are more frequent.

Most guidelines discourage breastfeeding while taking lithium, so feeding plans are worth discussing with the prescriber before the birth.44PubMed Central. Lithium during pregnancy and after delivery: a review

How Lithium Compares With Valproate

For an acute manic episode, about 66% on lithium and 72% on valproate recovered within 12 weeks, with similar side effects.45PubMed. A 12-week, open, randomized trial comparing sodium valproate to lithium in patients with bipolar I disorder suffering from a manic episode Many trials find the two broadly comparable.46PubMed Central. Lithium and Valproate in Bipolar Disorder: From International Evidence-based Guidelines to Clinical Predictors For preventing relapse, about 59% on lithium relapsed versus 69% on valproate over follow-up.47PubMed. Lithium plus valproate combination therapy versus monotherapy for relapse prevention in bipolar I disorder (BALANCE): a randomised open-label trial Combining both was clearly better than valproate alone.48PubMed. Lithium plus valproate combination therapy versus monotherapy for relapse prevention in bipolar I disorder (BALANCE): a randomised open-label trial

Several things shape the choice. Valproate isn’t advised for women who could become pregnant because of birth defect risk. Lithium needs more blood tests and kidney watching. Past response and side effects guide the decision, and it is made with the prescriber rather than by switching on your own.