Active Ingredients A to Z

Labetalol Labetalol is a combined alpha- and beta-blocker used to treat high blood pressure, including hypertension in pregnancy. It should never be stopped suddenly: abrupt withdrawal can trigger a dangerous rebound in blood pressure or chest pain. 1 medicine View → Labetalol Lamivudine Lamivudine is an antiviral used to treat HIV infection and chronic hepatitis B. In people with hepatitis B, stopping it without medical supervision can trigger a severe, sometimes life-threatening flare of liver disease. 5 medicines View → Lamivudine Lamotrigine Lamotrigine is an anticonvulsant and mood stabiliser used for epilepsy and bipolar disorder. It can cause a serious rash, including Stevens-Johnson syndrome, especially if the dose is increased too quickly, so it must be started and increased slowly. 1 medicine View → Lamotrigine Lansoprazole Lansoprazole is a proton pump inhibitor that reduces stomach acid to treat reflux and ulcers. Long-term use can weaken bones, lower magnesium levels, and reduce vitamin B12 absorption, so it should be used at the lowest effective dose for the shortest time needed. 1 medicine View → Lansoprazole Latanoprost Latanoprost is an eye drop that lowers pressure inside the eye to treat glaucoma and ocular hypertension. It can permanently darken the color of your iris and eyelashes, an effect that is usually irreversible. 1 medicine View → Latanoprost Ledipasvir Ledipasvir is an antiviral, usually combined with sofosbuvir as Harvoni, that clears chronic hepatitis C infection. In people who also have hepatitis B, it can trigger a serious reactivation of that virus, so hepatitis B status must be checked before starting. 1 medicine View → Ledipasvir Leflunomide Leflunomide is a DMARD used for rheumatoid arthritis and psoriatic arthritis; its active form stays in the body for up to two years, so it remains teratogenic long after the last dose and needs an accelerated elimination procedure before pregnancy. 1 medicine View → Leflunomide Lenalidomide Lenalidomide is a thalidomide-related medicine used to treat multiple myeloma and certain other blood cancers. It causes severe birth defects if taken during pregnancy, so it is only available through a strict pregnancy-prevention program, and it also raises the risk of dangerous blood clots and low blood cell counts. 1 medicine View → Lenalidomide Letrozole Letrozole is an aromatase inhibitor used to treat hormone-receptor-positive breast cancer in postmenopausal women; it lowers estrogen so much that it can thin bone, so bone density is checked before and during treatment. 1 medicine View → Letrozole Levodopa Levodopa, usually combined with carbidopa, is converted to dopamine in the brain to treat the movement symptoms of Parkinson's disease. It must never be stopped abruptly: sudden withdrawal can cause severe muscle rigidity, high fever, and confusion similar to neuroleptic malignant syndrome. 3 medicines View → Levodopa Levofloxacin Levofloxacin is a fluoroquinolone antibiotic used for infections when other antibiotics aren't suitable. It carries boxed warnings for tendon rupture, aortic aneurysm or dissection, and permanent nerve damage, so it is reserved for situations where safer alternatives won't work. 1 medicine View → Levofloxacin Levonorgestrel Levonorgestrel is a progestin used as emergency contraception and in regular birth control pills; it will not work if you are already pregnant and is most effective the sooner it is taken after sex. 3 medicines View → Levonorgestrel Levosalbutamol Levosalbutamol is a fast-acting inhaler that relieves asthma and COPD symptoms; needing it more often than usual is a warning sign of worsening disease that needs urgent medical review. 1 medicine View → Levosalbutamol Levothyroxine Levothyroxine is synthetic thyroid hormone (T4) used to treat an underactive thyroid, taken on an empty stomach at the same time each day. Too high a dose raises the risk of heart rhythm problems, especially atrial fibrillation in older adults, so treatment is guided by regular TSH blood tests. 1 medicine View → Levothyroxine Lidocaine Lidocaine is a local anesthetic used to numb skin, mucous membranes or a treatment area; applying too much over too large an area lets it enter the bloodstream and can cause seizures or a dangerous heart rhythm. 3 medicines View → Lidocaine Linagliptin Linagliptin is a DPP-4 inhibitor tablet that helps control blood sugar in type 2 diabetes; stop taking it and seek care immediately for severe, persistent abdominal pain, which can signal pancreatitis. 3 medicines View → Linagliptin Linezolid Linezolid is an antibiotic for serious resistant bacterial infections. Because it is a reversible MAO inhibitor, combining it with SSRI or SNRI antidepressants can cause life-threatening serotonin syndrome. 1 medicine View → Linezolid Liothyronine Liothyronine is synthetic T3, a potent, fast-acting thyroid hormone used to treat hypothyroidism under medical supervision. It is not an energy or weight-loss supplement, and excess doses carry real cardiac risks, including dangerous heart rhythms. 1 medicine View → Liothyronine Lisinopril Lisinopril is an ACE inhibitor for high blood pressure and heart failure; it must not be taken during pregnancy because it can seriously harm or kill an unborn baby, and it can rarely cause sudden, dangerous throat swelling (angioedema). 3 medicines View → Lisinopril Lithium Lithium is a mood stabilizer used long-term to treat and prevent episodes of bipolar disorder. It has a narrow therapeutic index, so regular blood, kidney and thyroid tests are essential to catch rising levels before they turn toxic. 1 medicine View → Lithium Lopinavir Lopinavir is an HIV protease inhibitor that is always combined with a small ritonavir dose to keep blood levels effective; that ritonavir component also causes many serious drug interactions, so check every other medicine you take. 1 medicine View → Lopinavir Losartan Losartan is an angiotensin receptor blocker (ARB) for high blood pressure; it must not be taken during pregnancy because it can seriously harm or kill an unborn baby's kidneys. 2 medicines View → Losartan Loxapine Loxapine is a first-generation antipsychotic used to treat schizophrenia. It carries a risk of neuroleptic malignant syndrome, a rare but life-threatening reaction, and can cause lasting movement disorders with long-term use. 1 medicine View → Loxapine Luliconazole Luliconazole is a topical antifungal cream used to treat fungal skin infections such as athlete's foot, jock itch and ringworm. If your skin has not improved after the recommended course, see a doctor, since the problem may not be fungal. 1 medicine View → Luliconazole Lurasidone Lurasidone is an atypical antipsychotic for schizophrenia and bipolar depression. It must be taken with a meal of at least 350 calories, since food roughly doubles how much of the drug your body absorbs. 1 medicine View → Lurasidone