Active Ingredients A to Z

Medroxyprogesterone Medroxyprogesterone is a synthetic progestogen given by injection for contraception, or by tablet to treat abnormal uterine bleeding and protect the uterine lining during hormone therapy; it raises the risk of blood clots, and long-term injectable use can reduce bone density. 2 medicines View → Medroxyprogesterone Mefenamic Acid Mefenamic acid is an NSAID used mainly for menstrual pain. Like all NSAIDs, it carries a risk of heart attack, stroke and serious stomach bleeding, so it is meant for short courses of no more than 7 days. 1 medicine View → Mefenamic Acid Melatonin Melatonin is a short-term sleep aid that resets your body clock rather than sedating you outright; it can cause daytime drowsiness and interacts with some prescription medicines. 3 medicines View → Melatonin Meloxicam Meloxicam is an NSAID taken once daily for arthritis pain and stiffness. Like all NSAIDs, it carries a risk of heart attack, stroke and serious stomach bleeding that rises with long-term use. 1 medicine View → Meloxicam Melphalan Melphalan is a cytotoxic chemotherapy drug for multiple myeloma. Its most important risk is severe bone marrow suppression, so regular blood counts are mandatory throughout treatment. 1 medicine View → Melphalan Memantine Memantine is an NMDA-receptor antagonist for moderate-to-severe Alzheimer's disease. It eases symptoms but does not stop or reverse the underlying disease, and the dose must be lowered in severe kidney impairment. 2 medicines View → Memantine Mesalazine Mesalazine is a 5-ASA anti-inflammatory used to treat and maintain remission of ulcerative colitis. Rare kidney injury means periodic kidney function tests are needed, and rarely it can paradoxically worsen colitis symptoms. 2 medicines View → Mesalazine Metaxalone Metaxalone is a sedating muscle relaxant used short-term for acute muscle spasm. It can impair coordination, so avoid driving, alcohol and other sedating drugs until you know how it affects you. 1 medicine View → Metaxalone Metformin Metformin lowers blood sugar in type 2 diabetes and must be paused before contrast-dye scans and during serious illness or dehydration, because continuing it in these situations can trigger rare but life-threatening lactic acidosis. 10 medicines View → Metformin Methocarbamol Methocarbamol is a sedating muscle relaxant used short-term for acute muscle spasm. Combining it with alcohol or other sedating drugs multiplies the drowsiness and can dangerously slow breathing. 1 medicine View → Methocarbamol Methotrexate Methotrexate is used at a low ONCE-WEEKLY dose for autoimmune diseases like rheumatoid arthritis and at much higher, specialist-supervised doses for cancer; taking the weekly arthritis dose every day by mistake has caused fatal overdoses. 1 medicine View → Methotrexate Methylprednisolone Methylprednisolone is a corticosteroid used to calm inflammation from allergic reactions, asthma flares and autoimmune diseases such as rheumatoid arthritis and lupus. After more than a few weeks of use it must be tapered off slowly rather than stopped, because your adrenal glands scale back their own hormone production during treatment. 2 medicines View → Methylprednisolone Metoclopramide Metoclopramide relieves nausea, vomiting and slow stomach emptying by speeding up gut movement and blocking the dopamine signal that triggers vomiting. Using it for more than about 12 weeks raises the risk of tardive dyskinesia, an often irreversible movement disorder, so treatment is normally limited to short courses. 2 medicines View → Metoclopramide Metoprolol Metoprolol is a beta-blocker used to treat high blood pressure, angina, arrhythmias and heart failure, and to protect the heart after a heart attack. Stopping it suddenly can trigger a rebound surge in heart rate and blood pressure, and even chest pain or a heart attack, so the dose must be tapered down gradually. 4 medicines View → Metoprolol Metronidazole Metronidazole is an antibiotic used for anaerobic bacterial and parasitic infections, including some dental, gut and vaginal infections. Alcohol must be avoided during treatment and for 48 hours after the last dose, the combination can cause a severe reaction. 1 medicine View → Metronidazole Miconazole Miconazole is an azole antifungal applied to the skin or vagina to clear fungal and yeast infections such as athlete's foot, ringworm and vaginal thrush. Even used this way, it can be absorbed enough to increase the blood-thinning effect of warfarin, so tell your prescriber if you take that medicine. 1 medicine View → Miconazole Midodrine Midodrine is an alpha-adrenergic agonist that raises blood pressure in people with orthostatic hypotension, a drop in blood pressure on standing that causes dizziness or fainting. Its main risk is supine hypertension, a dangerous rise in blood pressure while lying down, so it should never be taken within a few hours of bedtime. 2 medicines View → Midodrine Milnacipran Milnacipran is an SNRI (serotonin-norepinephrine reuptake inhibitor) used to treat fibromyalgia pain and fatigue. Like other antidepressant-class drugs, it carries an increased risk of suicidal thinking in people under 25, and combining it with an MAOI or another serotonergic drug can trigger serotonin syndrome, a medical emergency. 1 medicine View → Milnacipran Minocycline Minocycline is a tetracycline antibiotic used for acne and bacterial infections. Long-term use can cause drug-induced lupus and blue-grey skin pigmentation, and it must be avoided in pregnancy and in children under 8, since it permanently discolors developing teeth. 2 medicines View → Minocycline Minoxidil Minoxidil is a topical solution or foam that regrows scalp hair only for as long as you keep using it; a temporary increase in shedding is normal at the start, and it should be applied to the scalp only. 2 medicines View → Minoxidil Mirabegron Mirabegron is a beta-3 adrenergic agonist used to treat overactive bladder symptoms such as urgency, frequency and urge incontinence. It can raise blood pressure, sometimes significantly, so it should be avoided in severe uncontrolled hypertension and blood pressure should be checked periodically during treatment. 1 medicine View → Mirabegron Mirtazapine Mirtazapine is an antidepressant often chosen for people with depression alongside poor sleep or appetite loss, because sedation and weight gain are its two defining, dose-related side effects. 1 medicine View → Mirtazapine Misoprostol Misoprostol causes the uterus to contract, so it must never be used in pregnancy for stomach protection and can trigger miscarriage or birth defects if taken by mistake; under medical supervision it induces labor, manages miscarriage, controls postpartum bleeding, and prevents NSAID-related ulcers. 1 medicine View → Misoprostol Modafinil Modafinil is a wakefulness-promoting medicine for narcolepsy, obstructive sleep apnea, and shift-work sleep disorder; it can rarely cause a severe skin reaction and it lowers the effectiveness of hormonal contraceptives, so you need a backup birth control method while taking it. 1 medicine View → Modafinil Molnupiravir Molnupiravir is an oral antiviral for mild-to-moderate COVID-19 that inhibits viral replication. It is not authorised for pregnant people or anyone under 18 because of possible harm to fetal and bone or cartilage development. 1 medicine View → Molnupiravir Mometasone Mometasone is a corticosteroid used in creams for skin inflammation, nasal sprays for allergic rhinitis, and inhalers for asthma; the inhaled and nasal forms are preventers that will not stop a sudden attack, and long-term high-dose use of any form can thin skin or suppress your body's own cortisol production. 2 medicines View → Mometasone Montelukast Montelukast is a daily preventer medicine for asthma and allergic rhinitis, not a reliever for sudden attacks, and it carries a boxed warning for mood and behaviour changes, including rare suicidal thoughts. 1 medicine View → Montelukast Moxifloxacin Moxifloxacin is a fluoroquinolone antibiotic for respiratory, skin, abdominal, and eye infections; it carries a boxed warning for tendon rupture, aortic aneurysm or dissection, and irreversible nerve damage, and it can also prolong the heart's QT interval. 1 medicine View → Moxifloxacin Mycophenolate Mofetil Mycophenolate mofetil is an immunosuppressant used after organ transplant and in autoimmune disease, but it is a severe teratogen: pregnancy must be excluded and prevented with two reliable contraception methods before and during treatment. 1 medicine View → Mycophenolate Mofetil