Timolol is the non-selective Beta antagonist used as eye drops to treat increased pressure inside the eye such as in ocular hypertension and glaucoma. Timolol is also used for high blood pressure, chest pain due to insufficient blood flow to the heart, to prevent further complications after a heart attack, and to prevent migraines. Timolol is a beta1 and beta2 (non-selective) adrenergic receptor antagonist that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anesthetic (membrane-stabilizing) activity. Timolol, when applied topically on the eye, has the action of reducing elevated, as well as normal intraocular pressure, whether or not accompanied by glaucoma. Elevated intraocular pressure is a major risk factor in the pathogenesis of glaucomatous visual field loss and optic nerve damage. The precise mechanism of the ocular hypotensive action of Timolol is not clearly established at this time. Tonography and fluorophotometry studies of the timolol maleate ophthalmic solution in man suggest that its predominant action may be related to the reduced aqueous formation. However, in some studies, a slight increase in outflow facility was also observed. In a study of plasma drug concentration in six subjects, the systemic exposure to timolol was determined following once daily administration of Timolol Maleate Ophthalmic Gel Forming Solution 0.5% in the morning. The mean peak plasma concentration following this morning dose was 0.28 ng/mL. Side effects, when given in the eye, include burning sensation, eye redness, superficial punctate keratopathy, corneal numbness.

Hydromorphone (also known as dihydromorphinone and the brand name Dilaudid among others) is a more potent opioid analgesic than morphine and is used for moderate to severe pain. It can be administered by injection, by infusion, by mouth, and rectally. Oral bioavailability is low. The kidney excretes hydromorphone and its metabolites. Some metabolites may have greater analgesic activity than hydromorphone itself but are unlikely to contribute to the pharmacological activity of hydromorphone. With the exception of pruritus, sedation and nausea and vomiting, which may occur less after hydromorphone than after morphine, the side-effects of these drugs are similar. Hydromorphone interacts predominantly with the opioid mu-receptors. These mu-binding sites are discretely distributed in the human brain, with high densities in the posterior amygdala, hypothalamus, thalamus, nucleus caudatus, putamen, and certain cortical areas. It also binds with kappa and delta receptors which are thought to mediate spinal analgesia, miosis and sedation.

Pentazocine is a synthetically prepared prototypical mixed agonist-antagonist narcotic (opioid analgesic) drug of the benzomorphan class of opioids used to treat moderate to moderately severe pain. Pentazocine is sold under several brand names, such as Fortral, Sosegon, Talwin NX. Pentazocine acts as an agonist of κ-opioid receptors and as an antagonist of μ-opioid receptors. This compound may exist as one of two enantiomers, named (+)-pentazocine and (−)-pentazocine. Side effects are similar to those of morphine, but pentazocine, due to its action at the kappa opioid receptor is more likely to invoke psychotomimetic effects. High dose may cause high blood pressure or high heart rate.

Valproic acid (VPA; valproate; di-n-propylacetic acid, DPA; 2-propylpentanoic acid, or 2-propylvaleric acid) was first synthesized in 1882, by Burton. FDA approved valproic acid for the treatment of manic episodes associated with bipolar disorder, for the monotherapy and adjunctive therapy of complex partial seizures and simple and complex absence seizures and adjunctive therapy in patients with multiple seizure types that include absence seizures and for the prophylaxis of migraine headaches. The mechanisms of VPA which seem to be of clinical importance in the treatment of epilepsy include increased gamma-aminobutyric acid (GABA)-ergic activity, reduction in excitatory neurotransmission, and modification of monoamines. Recently, it was discovered that the VPA is a class I selective histone deacetylase inhibitor. This activity can be distinguished from its therapeutically exploited antiepileptic activity.

Oxymorphone is an analgesic that is FDA approved for the treatment of moderate to severe pain. It is also indicated for relief of anxiety in patients with dyspnea associated with pulmonary edema secondary to acute left ventricular dysfunction. Oxymorphone (brand names Opana, Numorphan, Numorphone) is a full opioid agonist and is relatively selective for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. Adverse reactions (≥ 2% of patients): seen with the immediate release tablet formulation Nausea, pyrexia, somnolence, vomiting, pruritus, headache, dizziness, constipation, and confusion. Concomitant use with serotonergic drugs may result in serotonin syndrome. Avoid use of mixed agonist/antagonist and partial agonist opioid analgesics with Opana because they may reduce analgesic effect of Opana or precipitate withdrawal symptoms.

Pethidine, also known as meperidine and Demerol, a narcotic analgesic that can be used for the relief of most types of moderate to severe pain, including postoperative pain and the pain of labor. Meperidine is an opioid agonist with multiple actions qualitatively similar to those of morphine. Most common adverse reactions were lightheadedness, dizziness, sedation, nausea, vomiting, and sweating. Pethidine has serious interactions that can be dangerous with monoamine oxidase inhibitors (e.g., furazolidone, isocarboxazid, moclobemide, phenelzine, procarbazine, selegiline, tranylcypromine). Pethidine can interact with muscle relaxants, some antidepressants, benzodiazepines, and ethanol.

Since its discovery as component of the tea leaf by Albert Kossel in 1888, the history of theophylline (CAS 58-55-9) has been a long and successful one. At the turn of the century, theophylline became less expensive due to chemical synthesis and was primarily used as diuretic in subsequent years. It was Samuel Hirsch who discovered the bronchospasmolytic effect of theophylline in 1992, however, despite this pioneering discovery theophylline continued to be used primarily as diuretic and cardiac remedy. The molecular mechanism of bronchodilatation is inhibition of phosphodiesterase(PDE)3 and PDE4, but the anti-inflammatory effect may be due to histone deacetylase (HDAC) activation, resulting in switching off of activated inflammatory genes. Theophylline is indicated for the treatment of acute exacerbations of the symptoms and reversible airflow obstruction associated with asthma and other chronic lung diseases, e.g., emphysema and chronic bronchitis.

Apomorphine (brand names: Apokyn, Ixense, Spontane, Uprima) is indicated for the acute, intermittent treatment of hypomobility, “off” episodes (“end-of-dose wearing off” and unpredictable “on/off” episodes) in patients with advanced Parkinson’s disease. Apomorphine has been studied as an adjunct to other medications. It is a non-ergoline dopamine agonist with high in vitro binding affinity for the dopamine D4 receptor, and moderate affinity for the dopamine D2, D3, and D5, and adrenergic α1D, α2B, α2C receptors. The precise mechanism of action as a treatment for Parkinson’s disease is unknown, although it is believed to be due to stimulation of post-synaptic dopamine D2-type receptors within the caudate-putamen in the brain.

Propoxyphene is a centrally acting opiate analgesic. Propoxyphene is an odorless, freely soluble in water, white crystalline powder with a bitter taste. In vitro studies demonstrated propoxyphene and the metabolite norpropoxyphene inhibit sodium channels (local anesthetic effect) with norpropoxyphene being approximately 2 fold more potent than propoxyphene and propoxyphene approximately 10 fold more potent than lidocaine. Propoxyphene and norpropoxyphene inhibit the voltage-gated potassium current carried by cardiac rapidly activating delayed rectifier (hERG) channels with approximately equal potency. It is unclear if the effects on ion channels occur within therapeutic dose range. Propoxyphene is indicated for the relief of mild to moderate pain.

Dihydrocodeine is an opioid analgesic used as an alternative or adjunct to codeine to treat moderate to severe pain, severe dyspnea, and cough. It is semi-synthetic, and was developed in Germany in 1908 during an international search to find a more effective antitussive agent to help reduce the spread of airborne infectious diseases such as tuburculosis. It was marketed in 1911. Dihydrocodeine is metabolized to dihydromorphine -- a highly active metabolite with a high affinity for mu opioid receptors. Dihydrocodeine is used for the treatment of moderate to severe pain, including post-operative and dental pain. It can also be used to treat chronic pain, breathlessness and coughing. In heroin addicts, dihydrocodeine has been used as a substitute drug, in doses up to 2500mg/day to treat addiction.