Active Ingredients A to Z

Efavirenz Efavirenz is an antiretroviral used with other HIV medicines to control the virus. It is taken at bedtime because of common central nervous system and psychiatric effects, and strict daily adherence is essential to prevent drug resistance. 1 medicine View

Eflornithine Eflornithine is used as a topical cream to slow unwanted facial hair growth, and as an intravenous treatment for advanced African sleeping sickness; the injectable form requires hospital monitoring for seizures and bone marrow suppression. 1 medicine View

Empagliflozin Empagliflozin is an SGLT2 inhibitor for type 2 diabetes, heart failure and chronic kidney disease that commonly causes genital yeast infections and can rarely cause euglycemic ketoacidosis, so nausea or vomiting need urgent review even with normal blood sugar. 1 medicine View

Emtricitabine Emtricitabine is an antiviral (NRTI) used with other drugs to treat HIV infection and for HIV pre-exposure prophylaxis (PrEP); stopping it in someone also infected with hepatitis B can trigger a severe flare of liver disease, and PrEP requires a confirmed HIV-negative test beforehand. 1 medicine View

Enalapril Enalapril is an ACE inhibitor used for high blood pressure and heart failure; it must not be used during pregnancy because it can cause serious injury or death to the developing baby, and it can rarely cause sudden, dangerous throat swelling (angioedema). 2 medicines View

Enclomiphene Enclomiphene is the isomer of clomifene used to raise testosterone in men with secondary hypogonadism, and it shares clomifene's caution around visual disturbances and mood changes. 1 medicine View

Entacapone Entacapone is a COMT inhibitor taken with levodopa for Parkinson's disease to smooth out "off" periods; stopping it or reducing levodopa suddenly can trigger a rare but serious reaction with high fever, confusion, and muscle rigidity, so any changes should be made gradually under medical supervision. 1 medicine View

Entecavir Entecavir is a nucleoside analogue used to treat chronic hepatitis B; stopping it can cause a severe, sometimes life-threatening flare of hepatitis, so liver function must be monitored closely for months after treatment ends. 1 medicine View

Eplerenone Eplerenone is an aldosterone-blocking diuretic used for high blood pressure and heart failure; it can raise blood potassium to dangerous levels, so regular blood tests are required and it must not be combined with strong CYP3A4 inhibitors such as ketoconazole or certain HIV medicines. 2 medicines View

Erythromycin Erythromycin is a macrolide antibiotic used for chest, throat, skin and some sexually transmitted infections. It can prolong the heart's QT interval, especially when combined with other QT-prolonging drugs or medicines that raise its blood levels. 1 medicine View

Escitalopram Escitalopram is an SSRI antidepressant used for depression and anxiety disorders. At higher doses it can prolong the heart's QT interval, raising the risk of a dangerous irregular heartbeat. 1 medicine View

Estradiol Estradiol is the main estrogen used in menopausal hormone therapy for hot flushes, night sweats and vaginal dryness; taken without a progestogen it raises the risk of endometrial cancer, and estrogen therapy overall carries a small added risk of blood clots and stroke. 2 medicines View

Estriol Estriol is a weak estrogen used as a vaginal cream, pessary or tablet to relieve dryness, irritation and urinary symptoms after menopause. Any unexplained vaginal bleeding must be checked by a doctor before or during use. 1 medicine View

Eszopiclone Eszopiclone is a short-term prescription sleeping tablet (a Z-drug) that can cause dependence with regular use and rare complex sleep behaviours, such as sleep-walking or sleep-driving, with no memory of them afterward. 1 medicine View

Ethambutol Ethambutol is an antituberculosis antibiotic used together with other drugs to treat tuberculosis. It can damage the optic nerve, so eyesight and colour vision must be checked before and during treatment. 1 medicine View

Ethinylestradiol Ethinylestradiol is the estrogen in most combined contraceptive pills; it raises the risk of blood clots, stroke and heart attack, and unopposed use in a woman with a uterus raises endometrial cancer risk. 12 medicines View

Ethionamide Ethionamide is a second-line antituberculosis medicine used in combination regimens for drug-resistant tuberculosis. It can injure the liver, so liver function must be monitored before and during treatment. 1 medicine View

Etodolac Etodolac is a non-steroidal anti-inflammatory drug (NSAID) used for arthritis and other pain. Like all NSAIDs it raises the risk of stomach bleeding and heart attack or stroke, especially with long-term use. 1 medicine View

Etoricoxib Etoricoxib is a COX-2 selective NSAID used for arthritis and acute pain. It is contraindicated in uncontrolled high blood pressure and in people with heart disease or a history of stroke because it raises cardiovascular risk. 1 medicine View

Everolimus Everolimus is an mTOR-inhibitor targeted cancer therapy also used to prevent organ-transplant rejection. It can cause serious infections and non-infectious lung inflammation, so new fever or breathing symptoms need urgent medical review. 1 medicine View

Exemestane Exemestane is a steroidal aromatase inhibitor used to treat hormone-receptor-positive breast cancer in postmenopausal women. It reduces bone density and increases fracture risk, so bone health is monitored during treatment. 1 medicine View

Ezetimibe Ezetimibe blocks cholesterol absorption in the gut to lower LDL cholesterol, usually alongside a statin. Combined with a statin it raises the risk of muscle damage, so report unexplained muscle pain right away. 2 medicines View