Imipramine, sold under the brand name Tofranil among others, is a tricyclic antidepressant (TCA) which is used mainly in the treatment of depression. It is also effective in treating anxiety and panic disorder. The drug is also used to treat bedwetting. It is taken by mouth. A long-acting form for injection into muscle is also available.

Isotretinoin, also known as 13-cis-retinoic acid and sold under the brand name Accutane among others, is a medication primarily used to treat severe acne. It is also used to prevent certain skin cancers, and in the treatment of other cancers. It is used to treat harlequin-type ichthyosis, a usually lethal skin disease, and lamellar ichthyosis. It is a retinoid, meaning it is related to vitamin A, and is found in small quantities naturally in the body. Its isomer, tretinoin, is also an acne drug.

Ketoconazole, sold under the brand name Nizoral among others, is an antifungal medication used to treat a number of fungal infections. Applied to the skin it is used for fungal skin infections such as tinea, cutaneous candidiasis, pityriasis versicolor, dandruff, and seborrhoeic dermatitis. Taken by mouth it is a less preferred option and only recommended for severe infections when other agents cannot be used. Other uses include in the treatment of excessive hair growth and Cushing's syndrome.

Lamotrigine, sold as the brand name Lamictal among others, is an anticonvulsant medication used to treat epilepsy and bipolar disorder. For epilepsy, this includes focal seizures, tonic-clonic seizures, and seizures in Lennox-Gastaut syndrome. In bipolar disorder, it is used to treat acute episodes of depression and rapid cycling in bipolar type II and to prevent recurrence in bipolar type I.

Lansoprazole, sold under the brand name Prevacid among others, is a medication which reduces stomach acid. It is used to treat peptic ulcer disease, gastroesophageal reflux disease, and Zollinger–Ellison syndrome. Effectiveness is similar to other proton pump inhibitors (PPIs). It is taken by mouth. Onset is over a few hours and effects last up to a couple of days.

Levofloxacin, sold under the trade names Levaquin among others, is an antibiotic. It is used to treat a number of bacterial infections including acute bacterial sinusitis, pneumonia, H. pylori, urinary tract infections, chronic prostatitis, and some types of gastroenteritis. Along with other antibiotics it may be used to treat tuberculosis, meningitis, or pelvic inflammatory disease. Use is generally recommended only when other options are not available. It is available by mouth, intravenously, and in eye drop form.

Lidocaine, also known as lignocaine, is a medication used to numb tissue in a specific area. It is also used to treat ventricular tachycardia and to perform nerve blocks. Lidocaine mixed with a small amount of adrenaline (epinephrine) is available to allow larger doses for numbing, to decrease bleeding, and to make the numbing effect last longer. When used as an injectable, lidocaine typically begins working within four minutes and lasts for half an hour to three hours. Lidocaine mixtures may also be applied directly to the skin or mucous membranes to numb the area.

Lisinopril is a medication of the angiotensin-converting enzyme (ACE) inhibitor class used to treat high blood pressure, heart failure, and after heart attacks. For high blood pressure it is usually a first line treatment, although in black people calcium-channel blockers or thiazide diuretics work better. It is also used to prevent kidney problems in people with diabetes. Lisinopril is taken by mouth. Full effect may take up to four weeks to occur.

Loratadine, sold under the brand name Claritin among others, is a medication used to treat allergies. This includes allergic rhinitis and hives. It is also available in combination with pseudoephedrine, a decongestant, known as loratadine/pseudoephedrine. It is taken by mouth.

Lorazepam, sold under the brand name Ativan among others, is a benzodiazepine medication. It is used to treat anxiety disorders, trouble sleeping, active seizures including status epilepticus, alcohol withdrawal, and chemotherapy-induced nausea and vomiting. It is also used during surgery to interfere with memory formation and to sedate those who are being mechanically ventilated. While it can be used for severe agitation, midazolam is usually preferred. It is also used, along with other treatments, for acute coronary syndrome due to cocaine use. It can be given by mouth or as an injection into a muscle or vein. When given by injection onset of effects is between one and thirty minutes and effects last for up to a day.

Losartan, sold under the trade name Cozaar among others, is a medication mainly used to treat high blood pressure. It is also used for diabetic kidney disease, heart failure, and left ventricular enlargement. It is taken by mouth. It may be used alone or in addition to other blood pressure medication. Up to six weeks may be required for the full effects to occur.

Lovastatin, sold under the brand name Mevacor among others, is a statin medication, to treat high blood cholesterol and reduce the risk of cardiovascular disease. It use is recommended together with lifestyle changes. It is taken by mouth.

Magnesium sulfate is an inorganic salt with the formula MgSO₄(H₂O)_x where 0 ≤ x ≤ 7. It is often encountered as the heptahydrate sulphate mineral epsomite (MgSO₄·7H₂O), commonly called Epsom salt. The overall global annual usage in the mid-1970s of the monohydrate was 2.3 million tons, of which the majority was used in agriculture.

Pethidine, also known as meperidine and sold under the brand name Demerol among others, is a synthetic opioid pain medication of the phenylpiperidine class. Synthesized in 1938 as a potential anticholinergic agent by the German chemist Otto Eisleb, its analgesic properties were first recognized by Otto Schaumann while working for IG Farben, Germany. Pethidine is the prototype of a large family of analgesics including the pethidine 4-phenylpiperidines, the prodines, bemidones and others more distant, including diphenoxylate and analogues.

Methadone, sold under the brand name Dolophine among others, is an opioid used for opioid maintenance therapy in opioid dependence and for chronic pain management. Detoxification using methadone can be accomplished in less than a month, or it may be done gradually over as long as six months. While a single dose has a rapid effect, maximum effect can take up to five days of use. The pain-relieving effects last about six hours after a single dose. After long-term use, in people with normal liver function, effects last 8 to 36 hours. Methadone is usually taken by mouth and rarely by injection into a muscle or vein.

Metoprolol, marketed under the tradename Lopressor among others, is a medication of the selective β₁ receptor blocker type. It is used to treat high blood pressure, chest pain due to poor blood flow to the heart, and a number of conditions involving an abnormally fast heart rate. It is also used to prevent further heart problems after myocardial infarction and to prevent headaches in those with migraines.

Minocycline, sold under the brand name Minocin among others, is a tetracycline antibiotic used to treat a number of bacterial infections such as pneumonia. It is generally less preferred than the tetracycline doxycycline. It is also used for the treatment of acne and rheumatoid arthritis. It is taken by mouth or applied to the skin.