Oxybuprocaine is a local anaesthetic. It may be less irritating than tetracaine, and the onset and duration of action are similar to tetracaine. Oxybuprocaine binds to sodium channel and reversibly stabilizes the neuronal membrane which decreases its...

Oxymetazoline Hydrochloride is an imidazoline derivative sympathomimetic amine. It is a direct agonist at α-adrenoceptors but has no action on β- adrenoceptors. It is used as a topical agent on the nasal mucosa, produces a rapid and long a...

Oxymorphone 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. The principal therapeutic action of oxymorphone is analgesia. Like all full opioid agonists,...

Oxyphencyclimine binds the muscarinic acetylcholine receptor. It may block all three types of muscarinic receptors including M-1 receptors in the CNS and ganglia, M-2 receptors in the heart (vagus) and M-3 receptors at the parasympathetic NEJ system....

Paracetamol has analgesic and antipyretic properties with weak anti-inflammatory activity. Paracetamol (Acetaminophen) is thought to act primarily in the CNS, increasing the pain threshold by inhibiting both isoforms of cyclooxygenase, COX-1, COX-2,...

The efficacy of Paroxetine is presumed to be linked to potentiation of serotonergic activity in the central nervous system resulting from inhibition of neuronal reuptake of serotonin (5-hydroxy-tryptamine, 5 HT). Studies at clinically relevant doses...

Prazosin causes a decrease in total peripheral vascular resistance through selective inhibition of postsynaptic alpha-1-adrenoreceptors in vascular smooth muscle. In hypertensive patients, blood pressure is lowered in both the supine and standing pos...

Sertraline has potent and selective inhibitory action on CNS neuronal reuptake of 5-HT resulting in increased 5-HT concentrations at the synaptic clefts, leading to facilitation of its sustained activity at the postsynaptic receptor sites. It ultimat...

A selective β2-adrenoceptor agonist with its main action on the uterus, causing relaxation. It reduces the intensity and frequency of contractions. Heart rate is also increased while diastolic pressure is reduced. May cause bronchial relaxation...

Ranitidine competitively blocks histamine at H2-receptors of the gastric parietal cells which inhibits gastric acid secretion. It does not affect pepsin secretion, pentagastrin-stimulated intrinsic factor secretion or serum gastrin.

Pyridoxine is a water-soluble vitamin which functions in the metabolism of carbohydrates, proteins and fats. It is essential in Hb formation and GABA synthesis within the CNS. It also aids in the release of glycogen stored in the liver and muscles.

Propranolol Hydrochloride is a B-adrenergic receptor blocking drug which is widely used in hypertension and angina pectoris. Propranolol antagonizes catecholamines at B-adrenergic receptors, thus prevents excess rate and force of contraction of the h...

The main site of anesthetic action is the nerve cell membrane where proparacaine interferes with the large transient increase in the membrane permeability to sodium ions that is normally produced by a slight depolarization of the membrane. As the ane...

Propafenone works by slowing the influx of sodium ions into the cardiac muscle cells, causing a decrease in excitability of the cells. Propafenone is more selective for cells with a high rate, but also blocks normal cells more than class Ia or Ib. Pr...

Procyclidine hydrochloride is an antimuscarinic antiparkinsonian agent of relatively low toxicity. It is a synthetic tertiary amine. This drug exerts their antiparkinsonian effect by correcting the relative cholinergic excess which is thought to occu...

Pethidine is a phenylpiperidine derivative opioid analgesic. It acts mainly as mu-receptor agonist. Like most, opioid analgesics, it mimics endogenous opioids by activating opioid receptors in the central and peripheral nervous system. It reduces the...

Pilocarpine Hydrochloride directly stimulates cholinergic receptors. It produces contraction of the iris sphincter muscle, resulting in pupillary constriction (miosis); constriction of the ciliary muscle, resulting in increased accommodation; and red...

Tropicamide binds to and blocks the receptors in the muscles of the eye (muscarinic receptor M4). Tropicamide acts by blocking the responses of the iris sphincter muscle to the iris and ciliary muscles to cholinergic stimulation, producing dilation o...