The Government has pledged to take control of medicine shortages for key drugs, including hormone replacement therapy (HRT), by restricting exports.
The Department of Health and Social Care (DHSC) said existing stocks of HRT will remain in the UK for NHS patients while manufacturing problems are resolved.
It is also allowing pharmacists to dispense different strengths of the antidepressant fluoxetine after most strengths of the drug went out of stock.
The move comes after a poll of pharmacists found most are experiencing shortages of every major type of medicine, including HRT, antidepressants and anti-epilepsy pills.
Blood pressure drugs, contraceptives, painkillers and skin creams are also among those in short supply.
The 402 community pharmacists who responded to the Chemist and Druggist survey said HRT drugs were most commonly in short supply, with 84 per cent struggling to get hold of them.
The DHSC said the move to limit exports of HRT backs up other efforts to reduce medicine shortages across the UK.
The restrictions will stop medicine wholesalers from taking advantage of short supplies by parallel exporting where companies buy medicines meant for UK patients and sell them on for a higher price in another country.
A total of 19 HRT drugs will be subject to the new export restrictions.
Similar measures are in place in other European countries, including France and Spain.
A further five medicines will also be restricted, including all adrenaline auto-injectors and Hepatitis B vaccines.
The Government has also introduced serious shortage protocols for fluoxetine for patients with a prescription for the 10mg, 30mg and 40mg capsules, all of which are out of stock.
The 20mg capsules, tablets and oral solutions are still available and pharmacists will be able to dispense those without patients having to go back to their GP for a new prescription.
The DHSC says there is no evidence that Brexit is causing problems with medicines supply although serious shortage protocols could be used as a tool if there is any Brexit-related disruption.
Health Secretary, Matt Hancock, said: "I know how distressing medicine shortages can be for those who rely on drugs like HRT and it's absolutely crucial patients can always access safe and effective treatments through the NHS.
"The new measures we're introducing today will help us ensure patients get the medicines they need and the high quality care they deserve.
"Helping the NHS is a priority for this Government, and people should be fully reassured that we will always act to ensure that there is an adequate supply of the medicine you need."
The DHSC said the medicine supply chain "is complex and highly regulated, so problems can arise for a variety of reasons, including manufacturing issues or problems with raw ingredients."
There are currently around 360,000 prescriptions of HRT medicines dispensed every month on the NHS.
Companies that break the new rules could face action from the Medicines and Healthcare products Regulatory Agency (MHRA).
Dr Rick Greville, director of supply chain at the Association of the British Pharmaceutical Industry (ABPI), said: "The decision to take precautionary measures to protect medicines supplies will be very much welcomed by our members.
"It means that these stockpiles of medicines which companies have built over previous months are better protected and available for use only by the NHS patients for which they were intended.
"Companies can now work with the department to identify any problem areas."